Sponsor Message:
Civil Aviation Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
FAA Grounds 787 Part 12  
User currently offline777er From New Zealand, joined Dec 2003, 12189 posts, RR: 18
Posted (1 year 7 months 3 days 20 hours ago) and read 31189 times:
AIRLINERS.NET CREW
FORUM MODERATOR

Link to thread #11 FAA Grounds 787, Part 11 (by 777ER Feb 23 2013 in Civil Aviation)

WARNING: Due to thread 9 going off topic quickly and turning into a 'battle ground', the moderators will be watching this thread frequently and ANY offending/rule breaking posts will be removed. Please respect each others right to have their opinion.

213 replies: All unread, showing first 25:
 
User currently offlinercair1 From United States of America, joined Oct 2009, 1323 posts, RR: 52
Reply 1, posted (1 year 7 months 3 days 14 hours ago) and read 30747 times:
AIRLINERS.NET CREW
CUSTOMER SERVICE & SUPPORT

I'm reposting this from the end of the last string. I put a fair amount of effort into it and if it is at the end of the string - it is lost. Hope the mod's don't mind. The links to quoted replies do not work - obviously - so I deleted them.

Quoting Wisdom (Reply 208(prev thread)):

I suspect 3 possible sources of issues:
1. Wild frequency generation is not converted as accurately as required, causing the battery to even out the loads and heat up under a thermal fatigue effect. The only way to find out is to fly or do run-ups on the accident NH B787 engines and hook some ultra-sensitive measuring equipment.
2. Static electricity build-up caused by sensing or converting equipment or even by the fuselage.
3. Earthing problems. On aluminum aircraft the metal fuselage is your negative port, what happens on a CFRP aircraft? Can a CFRP fuselage be conductive enough that it does mitigate the negative load sufficiently to avoid that your battery or your fuselage become a capacitor?

A combination of the above is also possible.

From a EE standpoint. (Yes - I'm a Fire Fighter, but my 'job' is a EE - BS, MS, Ph.D.) none of these are overlly compelling - basically you are throwing stuff on the wall and hoping it sticks.

1 - Wild frequency generation.
"Wild" sounds impressive and dangerous - but it is not. It just means variable frequency. The VFSG on the 787 generate 235V AC at a frequency of 360-800 hz - they are not generators, they are alternators and by using direct drive and variable frequency the complex mechanical systems required to turn the alternators at a fixed speed are eliminated.
Yes - that is correct, the frequency of AC power is directly related to the rotation speed of the alternator.
What is done in the 787 with this power is 4 fold.
A) Large, frequency insensitive, loads are driven directly by the 235V Variable Frequency current. Things like wing de-ice heaters do not care about the frequency.
B) Some of the power is converted to 115AC 400Hz - traditional power in the aircraft. This is done by a device called an Auto-Transformer. Auto transformers convert both frequency and voltage.
   The auto-transformer is the electrical equivalent of the constant speed mechanical drive in a traditional a/c system. Frankly - an auto-transformer is far more reliable.
C) Some of the power is converted to 28V DC - this is done with a rectifier. It is really a transformer-rectifier so that it can deal with the variable frequency. In the simplest configuration - a rectifier is a diode and capacitor. Of course, these are far more sophisticated. Again - nothing special here.
D) The last conversion is to 270VDC. This is a voltage step up as well as a rectification - so an auto transformer/rectifier is used.
   The reason you use high voltage DC is to minimize wire size. To deliver 1000 watts at 27VDC takes 37 amps -a large wire. To deliver that same 1000 watts at 270VDC is 3.7 amps.

   - BTW - the alternator in your car is a 'wild frequency'. It rectifies it to 14.7ish volts DC, and many cars then have inverters to power AC. Sound familiar? Same approach - smaller and not as well regulated. Some hybrids even use a pancake motor between the engine and the tranny - and use that as the starter.

Here is a diagram showing it:
B787 Electrical Architectur

B787 Electrical Architecture

2. Static electricity build-up caused by ..
Static discharge - or ESD (electro-static discharge) is always a design concern - however, it is much more likely to cause issues with small electronics that large power system. While there is plenty of potential (voltage) and energy to damage a microchip, that is not the case for large power systems. They can absorb ESD events with no issue. If the problems were were seeing were electronic components failing (I'm not talking chargers pushing lots of current), then ESD woudl be a likely culprit.
   Power surges from other high power system - i.e. ground systems - are much more likely IMO - if we are taking externally caused damage at all.

3. Earthing problems (we call them grounding problems here in the states).
I think it is very unlikely that Boeing, or anybody, is shunting large currents through the skin of either a carbon fiber or aluminum skin. Small currents - sure. Larger ones, no way. Again - if we were seeing damage to electronic components (chips and such), then yes. Batteries and large loads - not likely.
   One aspect of grounding problems that could cause issues would be a high resistance in the ground side of a voltage sensing circuit. That could cause the voltage to be mis-read as low and the applied voltage raised. But - you can be sure that if your are wiring a sensitive sensing circuit - you are not relying to the stray return path of a aluminum or CF skin.

Of course - the predictable response will be that something ESD'ish or grounding problems are causing problems with the chargers. Have we seen any evidence of charger problems (not wiring issues)?

Quoting BoeingVista (Reply 210-prev thread):

Boeing for whatever reason, chose the one with the most power but also the most volatile.

Because...

Quoting Stitch (Reply 203-prev thread):

Boeing and Cessna likely chose lithium cobalt oxide because even though it was known to be a volatile cathode chemistry, it was also one of the more mature ones a decade ago when they started development of their respective programs. So having made the decision to use lithium-ion batteries, both Boeing and Cessna went with the one with the most knowledge and experience rather then choose a new, untested cathode chemistry even if it appeared to be less volatile. There were risks with LCO, but they were known risks and Boeing (incorrectly) believed they had addressed them.


Finally...
Quoting ServantLeade (Reply 211-prev thread):
Quoting
Sorry, but that makes absolutely no sense. Boeing produces the airplane and the batteries are part of it, and you say that Boeing is not at fault when they fail?

Wrong - Boeing is "responsible" but may not be "At Fault". When the headlight on your brand new car fails because it was defective, you go to the car dealer. They are "responsible"- and they give you a new headlamp. But the party at "fault" is the one who produced the defective headlamp. Last I checked, no car manf was making headlamps.



rcair1
User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 2, posted (1 year 7 months 3 days 14 hours ago) and read 30690 times:

Quoting rcair1 (Reply 1):
Wrong - Boeing is "responsible" but may not be "At Fault". When the headlight on your brand new car fails because it was defective, you go to the car dealer. They are "responsible"- and they give you a new headlamp. But the party at "fault" is the one who produced the defective headlamp. Last I checked, no car manf was making headlamps.

Your rationale for differentiating responsibility from fault is based on the assumption that the battery issue is isolated to the battery and that Boeing bares no responsibility for its design shortcommings given the application, neither of which are valid. Boeing owns this problem from A to Z.

[Edited 2013-03-01 06:34:09]

User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 3, posted (1 year 7 months 3 days 13 hours ago) and read 30537 times:

Quoting ServantLeader (Reply 2):
Boeing owns this problem from A to Z.

I don't think anyone disputes the fact that Boeing owns the problem (especuially not Boeing). But "A to Z" suggests that Yuasa, Thales, Securaplane, ANA, JAL, UA, etc. are all innocent bystanders. The official investigations have so far produced no facts to support this.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 4, posted (1 year 7 months 3 days 9 hours ago) and read 30185 times:

As rcair1 is telling others to be exact on technical details, I have to nitpick a bit.

An alternator is always a generator, a generator is a device converting mechanical energy into electrical energy it includes alternators, dynamos and so on.

I do hope that Boeing is not using many transformers or auto transformers in the B 787, they are old fashioned, heavy and not used in modern AC/DC or DC/DC converters, frequency controllers, power supplies etc, switched thyristors are used instead.

Variable frequency generators are of course state of the art, apart from air planes and cars you find them in windmills, ships, some modern hydro power stations and so on. You run that through a frequency converter (switched thyristors) and you have the right frequency.
The part were wisdom (user) is coming in, you can get out of a badly designed or even broken frequency converter or switching power supply high frequency waves.
I expect Boeing to use good equipment not emitting high frequency waves.
And if something is broken, a Boeing engineer will find an oscilloscope to find that culprit.

Static electricity has been the bane of electrical installations. That is why you ground (or earth) everything in sight and bad grounding has been the reason for many strange electrical happenings.
You put a florescent lamp above some sheet metal and you get a static charge for example.
Lets not forget that the ground wire of the battery in the JAL B 787 was broken.

The Americans have so nice words "wild frequency generation" sounds so much more macho than variable frequency.

Some reading material on transformer you also find auto transformer.
http://www.electrical4u.com/electrical-transformer/index.php
I would say have look at the Wikipedia but that gives always a horrible reaction.

[Edited 2013-03-01 11:21:19]

User currently offlinercair1 From United States of America, joined Oct 2009, 1323 posts, RR: 52
Reply 5, posted (1 year 7 months 3 days 5 hours ago) and read 29695 times:
AIRLINERS.NET CREW
CUSTOMER SERVICE & SUPPORT

Quoting mjoelnir (Reply 4):
An alternator is always a generator, a generator is a device converting mechanical energy into electrical energy it includes alternators, dynamos and so on.

A generator can also generate steam, oxygen, nitrogen, hot air (or am I confusing that will that some a.net posters. The point is that from an electrical engineering standpoint, not a generic standpoint - they are alternators, not generators.

As for the auto-transformers. As you see from the diagram I attached - which is a Boeing diagram, they call them "ATRU - Auto Transformer Rectifier Unit" and "ATU" - Auto Transformer Unit. I suspect these are advanced versions, but since I have no insider information on what the really use - I reported what they say. By the way - I most of this is from Hamilton Sundstrand - which also provides multiple subsystems for other aircraft manufacturers.
Here is a youtube video by Hamilton Sundstrand about their role in the 787.
http://www.youtube.com/watch?v=dPltBtBa7VQ&feature=player_embedded#!
It is not clear if they make the ATRU/ATU/TRU systems.



rcair1
User currently offlineKaiarahi From Canada, joined Jul 2009, 3011 posts, RR: 28
Reply 6, posted (1 year 7 months 3 days 4 hours ago) and read 29683 times:

Quoting ServantLeader (Reply 2):
Your rationale for differentiating responsibility from fault is based on the assumption that the battery issue is isolated to the battery and that Boeing bares no responsibility

Rubbish. That's not what rcair1 was saying. In my professional life, I'm accountable for many things where the "fault" was not mine, but I remain accountable. My executive assistant or my junior executives may make a mistake which is their "fault" but for which I'm nevertheless accountable to my client, even though I did not make the mistake. That doesn't mean I should personally supervise every single action they take - it just means I should hire carefully with due diligence and establish clear escalation matrices. Yuasa, Securaplane, Thales and Hamilton Sundstrand have specific, demonstrated expertise and I'm sure Boeing exercised due diligence before engaging them to design / produce components.

Some of the (respected) component / systems suppliers for the 787 include:

Mitsubishi (wings)
Kawasaki (fuselage sections)
Latecoere (passenger doors
Saab (cargo doors)
Messier-Dowty (landing gear)

Check out your own PC. Pretty much every component (motherboard, video board, audio, sound, RAM, fan, software) has a different manufacturer. If they didn't exist, you wouldn't have a PC.



Empty vessels make the most noise.
User currently offlineWildcatYXU From Canada, joined May 2006, 2623 posts, RR: 5
Reply 7, posted (1 year 7 months 3 days 2 hours ago) and read 29370 times:

Quoting rcair1 (Reply 5):
As you see from the diagram I attached - which is a Boeing diagram, they call them "ATRU - Auto Transformer Rectifier Unit" and "ATU" - Auto Transformer Unit. I suspect these are advanced versions, but since I have no insider information on what the really use - I reported what they say.

Well, even without an insider information is clear that these would be very advanced electronic devices. For starters, a plain auto transformer would convert the 230V variable frequency AC only into 115V variable frequency (not to mention that it would be large and heavy). To gain 115V/400Hz AC a voltage/frequency converter is needed. I have zero reason to believe it's not state of art. Similarly, the 230V/28V TRU is definitely not just a transformer with a diode bridge rectifier...
oh, how I wish to see at least the block diagram of both units.


User currently offlineYVRLTN From Canada, joined Oct 2006, 2477 posts, RR: 0
Reply 8, posted (1 year 7 months 3 days ago) and read 29169 times:

Quoting mjoelnir (Reply 4):
Static electricity has been the bane of electrical installations. That is why you ground (or earth) everything in sight and bad grounding has been the reason for many strange electrical happenings.

So if there were faulty connectors, or if they were not installed correctly, even if it didnt result in arcing exactly it wouldnt be earthed, so could that result in the battery issues we have seen because it is the "weakest link" in the system?



Follow me on twitter for YVR movements @vernonYVR
User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 9, posted (1 year 7 months 2 days 22 hours ago) and read 28541 times:

Quoting rcair1 (Reply 1):
Auto transformers convert both frequency and voltage.

No way you can control frequency with a auto transformer.

Auto transformer is kind of electrical transformer where primary and secondary shares same common single winding.
see:
http://www.electrical4u.com/electric...l-transformer/auto-transformer.php

I do not no why your diagram uses words like Auto transformer rectifier unit or Auto transformer unit.
Perhaps it sounds nice like wild frequency generation.

We in my company have not been using transformers with an rectifier to produce DC for around 25 years in the machines we produce.

The Equipment we are using today is called in the industry an AC to DC converter.
In the computer industry they call it a switching power supply.
The definition what it does is usually done with defining the input and defining the output.
The way it works is roughly using a rectifier with switched thyristors (IGBT).

Brown area 28V DC
25 years ago we would use a transformer from AC 230 V to AC 28 V, than a rectifier for AC to DC and a bank of capacitors to clean away the waves. For an output 30 V 10 A it would have been about 15 Kg.
Today the transformer less AC to DC converter does it with about 1.5 kg

Blue area 115V AC variable frequency
Frequency converter.
In the old days you used a motor and generator set. Very heavy and not really good for variable frequency's.
I do not know a way to do this with transformers
That was why fixed frequency was used.

Today you use also switched thyristors.
First you rectify and than you use thyristors to build the sine wave.
You control the frequency and can take down the output Voltage.
That is why you can today use variable frequency generation.

Green area.

230V AC to 260V DC

In the old days you would use an transformer to up the voltage and than an rectifier to make the DC.

Today you would up the voltage with a voltage multiplying rectifier and use a DC to DC converter with switched thyristors.
Or a voltage multiplying rectifier with switched thyristors.

No transformers or auto transformers in sight.


User currently offlinesweair From Sweden, joined Nov 2011, 1824 posts, RR: 0
Reply 10, posted (1 year 7 months 2 days 22 hours ago) and read 28525 times:

Is there Li-ion chemistry's in the market that are considered as safe as old batteries? Readily available? But changing chemistry will certainly not be a trivial task, as it has the be designed to fit the electrical system and everything else.

User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 11, posted (1 year 7 months 2 days 15 hours ago) and read 27717 times:

Quoting rcair1 (Reply 1):
Quoting Kaiarahi (Reply 11):

What I find strange in the diagram is the 260 V DC.

Usually when you go for lightweight you would not convert AC to DC and up the voltage.
The best way would be to generate the right voltage in AC and rectify to DC.
If you want 400 V DC power you produce 400 V AC in the generator, and so on.
You produce the highest voltage you need and cascade down.
I speculate if the number for the 260 V DC is the top voltage of a pulsing wave or if it is the effective voltage.

The power supply's for the two lower voltages 115 AC or 28 V DC, usually do not care if you feed them
260 V AC or 230 V, they usually cover a range of Input voltages.

Transformers are heavy, you usually try to do without them for less weight.

You still use a lot of transformers to increase voltage or decrease voltage in Power distribution systems.
I would not expect them aboard an modern aeroplane.
Perhaps on board a AN 124 transporting them.

Regarding transformer.

The difference between a transformer and an auto transformer is, that a transformer uses double sets of windings one each for inputs and one for outputs.
The auto transformer uses the same windings for in and output.

[Edited 2013-03-02 05:25:06]
Big version: Width: 344 Height: 288 File size: 5kb
Big version: Width: 344 Height: 288 File size: 5kb


[Edited 2013-03-02 05:28:58]

User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 12, posted (1 year 7 months 2 days 15 hours ago) and read 27615 times:

I have not worked with an alternator on board a modern commercial aeroplane.

But the alternators on board a ship do usually not only have a floating frequency, 45 to 65 Hz but also a floating voltage,
380 V AC to 440 V AC. The higher voltage is associated with the higher frequency.
For my equipment I have to install usually a frequency converter, out of that I would get a steady frequency and a fast voltage adjusted to the lowest voltage I will get, on the example above it would be 380 V.

[Edited 2013-03-02 05:57:08]

User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 13, posted (1 year 7 months 2 days 14 hours ago) and read 27502 times:
Support Airliners.net - become a First Class Member!

Quoting sweair (Reply 10):
Is there Li-ion chemistry's in the market that are considered as safe as old batteries?

Lithium iron phosphate (FiFePO4) should be closest It has moderate power density (someone noted Boeing would need to add one additional cell to meet the same capacity as the current lithium cobalt oxide unit) and it effectively does not enter thermal runaway (temperature rise is on the order of a few degrees Centigrade per minute compared to a few hundred degrees per minute for LiCoO2).


User currently offlinecomorin From United States of America, joined May 2005, 4896 posts, RR: 16
Reply 14, posted (1 year 7 months 2 days 14 hours ago) and read 27450 times:

Quoting mjoelnir (Reply 14):

I'm an ex-EE and I appreciate your posts. It's been 50 years since I used an auto-transformer but surprised that they are used on aircraft given the heat losses from hysteresis. Has that tech changed over the years?

Modern systems indeed use high-current solid-state devices for both rectification and frequency control. A friend of mine (ex-Bell Labs) is working on programmable software-driven thyristors so much is happening in this field.

I am sure that rcair1 knows what he is talking about, given his excellent posts, and is not implying that we are using 19th century technology on the 787!  


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 15, posted (1 year 7 months 2 days 11 hours ago) and read 27255 times:

I am an mechanical engineer with a diploma from a German school.
My diploma work in 1983 was about computer programs to help to design cranes.
I have build my own computer hardware and boards and programmed in basic, Fortran, pascal and assembler and now in C++.
I have programmed industrial controllers for example Siemens in step.
In one firm I sell equipment for tank trucks, fuel depots and aircraft refuelling. I also sell ex proofed electrical equipment.
In another company I sell equipment for the fish processing industry. We have a service shop, machine tool shop, produce machines, sell other machines on land and on ships.
I have been a volunteer fire fighter and mountain rescue.
I am a private pilot.

I started posting here when I could not read any longer without getting angry the following statemenst regarding the B 787 battery incidents:

- the containment worked (if it had worked the B 787 would not be grounded)
- the containment contained the flames (the Boston fire crew does not agree)
- when the NTSB talked about flammable liquid, and posters disregarding that as a danger
- there was no real danger, nothing happened
- the B 787 was prematurely grounded
- on the ANA flight there was no danger, the battery did not ignite.

Are that the "experts"?

When I hear vapours of flammable liquids are vented into an electronics bay, the cold sweat runs down my neck and I understand the instant grounding.

If somebody asks me what could ignite the vapours, my answer is the electrical cabinet.
You switch a mechanical relay and you have your spark plug.
That is why in an ex proofed environment you have a case around the relay filled with inert gas or equipment that can not produce a spark which excludes all high power equipment.

I do not like to hear if one has a different opinion, that one should to listen to the "experts". Physical and chemical properties do not change because they are applied to a aeroplane, we all work with the same stuff.

I can agree with many posts of rcair1, but in this case I do not agree.

I have never seen an auto transformer used to control frequency of an action current.

Using AC/DC, DC/DC and frequency conversion is my daily bread.

When I see this name, Auto Transformer Unit, I assume they do not talk about an auto transformer, but that the sales people had a field day finding catchy names.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 16, posted (1 year 7 months 2 days 11 hours ago) and read 27170 times:

Quoting 777er (Thread starter):
230V AC to 260V DC

Quoting myself in reply 7

In the old days you would use an transformer to up the voltage and than an rectifier to make the DC.

Today you would up the voltage with a voltage multiplying rectifier and use a DC to DC converter with switched thyristors.
Or a voltage multiplying rectifier with switched thyristors.

Here I was talking absolute nonsense. You could use voltage multiplying rectifiers, but it is a bad solution for high power application.
You would need a transformer here to go from 230 V AC to 260 AC to rectify to 260 V DC.

I still do not understand why somebody would design a system that way, as you could either use 230 V DC or up the alternators to 260 V AC and you get rid of quite few Kg in transformers.

[Edited 2013-03-02 09:32:29]

User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3413 posts, RR: 4
Reply 17, posted (1 year 7 months 2 days 10 hours ago) and read 26973 times:

Quoting Stitch (Reply 15):
it effectively does not enter thermal runaway (temperature rise is on the order of a few degrees Centigrade per minute compared to a few hundred degrees per minute for LiCoO2).

even better from the chart posted way back in this mess of threads its peak temp was roughly 1/2 that of the current battery chemistry. Which should prevent the burning of the connector through the containment vessel we saw in the boston fire. I'm not sure if the containment could be lighter as it looks like they were already running not too far over the minimum wall thickness required for handling during MX.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 18, posted (1 year 7 months 2 days 9 hours ago) and read 26921 times:

RCair, you could be an electrical engineer all you want, I've seen very clever guys with 30 years of experience as a B2 electrical engineer working on aircraft and knowing it inside out, struggling to find an answer for simple problems in a simple wiring system that I solved in 30 seconds.

TRU converts AC current and tension into a pulsating current and tensions.
The big difference between a wild frequency and constant frequency generation is that in the latter case, both current and tension will pulsate at the same frequency while in the former, they will not be.

In wild frequency systems, these pulses will not be constant and it's very hard to filter them out using capacitor and regulator systems. So you have to place several of these in series to hope to achieve the required result.

360-800 Hz sounds about right given N2 rpm range.The frequency range is not so vast but still vast enough to create undetectable repetitive micro-surges that the filters can't filter out.

Given both battery incidents started occurring at or close to the ground when the engines and their generators were providing the most unstable frequency regimes, ie when the power lever is most moving during the approach, taxi and departure phases, it's not unlikely that this is what's causing the battery to heat up.

Quoting rcair1 (Reply 1):
  - BTW - the alternator in your car is a 'wild frequency'. It rectifies it to 14.7ish volts DC, and many cars then have inverters to power AC. Sound familiar? Same approach - smaller and not as well regulated. Some hybrids even use a pancake motor between the engine and the tranny - and use that as the starter.

Many cars have inverters to power AC? Camping cars and some cars that have sockets for cooling boxes maybe, most cars only have DC.
What you fail to grasp is that while your B787's battery is about the same size as your average car battery, your car's generator generates maybe around 1kVA, while your engines are around 1000kVA.
The issue is not the voltage, as it will be around 115V, the issue is your huge current pulses.

When you have a 1kVA generator like in a car, your current pulses will be much smaller and less variable.
So there, even if you have a wider RPM and frequency range it doesn't matter because the pulses are barely detectable.

http://electriciantraining.tpub.com/14179/img/14179_172_2.jpg

Do the math, 1kVA, 12V. How much is your current?
Do the math, 1000kVA, 115V. How much is your current?
So as you realise, the car/B787 comparison doesn't stand as current pulses are in different dimensions.


User currently offline2175301 From United States of America, joined May 2007, 1072 posts, RR: 0
Reply 19, posted (1 year 7 months 2 days 8 hours ago) and read 26741 times:

Please be aware that industries develop their own internal lingo to describe things that is carried forward many decades.

As such, I have no doubt that the current use of the term "auto-transformer" does not mean an actaul "auto transformer" with windings and steel plates; just the modern equivalent that performs essentially the same function as the original "auto transformers" 30 or 40 years ago.

That should clear up some confusion.

Another item: I do remember that there was a way to wind an old style transformer such that the output was at 1/2 or 1/3 the frequency of the input. My memory is this involved multiple coils and some fancy wiring; but it did exists. It would not surprise me if this was called some kind of "auto frequency converting transformer" which got shortened to "auto-transformer" for the purpose of the airline industry.

The final item: Modern voltage and frequency conversion circuits are way beyond the example above in Wisdom's post 20 to effectively make his diagram and argument about possible frequency issues meaningless. Those issues were solved several decades ago.

I have decade old standard industrial pure sine wave output back up power supplies in my house which take 90-500 V input 48-62 Hz input, and outputs on one plug a pure DC output (I am not sure of the voltage - but the same as the battery circuit); and I have selected it to output 120V pure sine wave 60 Hz on the receptacles (I can program for several options). The batteries supply up to several days of power in the event of a power outage. I have this for my boiler/hot water (home heating) and for some medical equipment I own. I buy these used when they come up on the market. While I stick specifically to Liebert brand equipment in a specific model series for standardization; at least a half dozen companies have been selling this kind of equipment to companies and industry for 15+ years.

To suggest that Boeing (and the various companies involved in the design of the 787 electrical system) are not even using standard commercial circuits that eliminate the pass though noise of simple rectifiers and have been marketed by multiple companies for over 15 years in standard commercial equipment does not pass the common sense test.


Have a great day,


User currently offlineairtechy From United States of America, joined Dec 2006, 504 posts, RR: 0
Reply 20, posted (1 year 7 months 2 days 8 hours ago) and read 26646 times:

I suspect that a discussion of the aircraft electrical system at this level of detail should be carried on in the tech/ops forum. Also, I certainly don't and I suspect no one on this forum knows what is in the very upper level block diagrams of the electrical boxes. Functionality is often described in terms carried forward by years of common usage.

Unless I was able to peruse released schematics, I certainly wouldn't feel qualified to comment on the 787 electrical system and certainly not to criticize others on their comments about it.

I doubt that Boeing....or their subcontractors.... would use anything other than the latest technology despite how the block diagram may be labeled.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 21, posted (1 year 7 months 2 days 8 hours ago) and read 26590 times:

Sorry, when your current is alternating or pulsating 800 times a second at 10.000 amperes, it's no longer noise we're talking about (remember that 1A can kill you), it's an "EMP". Even if the DC system doesn't require that much of the current, you still have to try to filter the ample pulses, plus all the variables you deal with such as switching other major "customers" off.

Whatever is used on aircraft is 20-30 years old technology in other industries. The technology has to be proven in other heavy duty applications before they can be installed on aircraft.

On A330's, you still have diode-based rectifier units. Having no knowledge of what is the standard outside the aerospace, this is what I know and it's been in use since a long time. It's proven to work well.

When you have a system pulsating at 800hz, I can't help but wonder whether a recording system like the FDR can record a momentary surge lasting only one period of 0,00125 seconds or a few such periods. Such a short surge would not be large enough to make it to your frequency read-out anyway, and that's usually where the recording is taken.
Also what happens when you switch heavy users like the huge airco system on/off?

Dear airtechy, I am trying to keep everything in simple terms for everything to be understandable for everyone to follow. It's useless to throw a bunch of technical terms and to pretend to know something better, we're not talking about rocket science here, it's simple AC to DC conversion.

Don't you suspect that AC to DC conversion can yield impurities resulting in problems at the battery level?

[Edited 2013-03-02 13:05:07]

User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 22, posted (1 year 7 months 2 days 7 hours ago) and read 26481 times:

Quoting Wisdom (Reply 24):
Sorry, when your current is alternating or pulsating 800 times a second at 10.000 amperes, it's no longer noise we're talking about (remember that 1A can kill you), it's an "EMP". Even if the DC system doesn't require that much of the current, you still have to try to filter the ample pulses, plus all the variables you deal with such as switching other major "customers" off.

Whatever is used on aircraft is 20-30 years old technology in other industries. The technology has to be proven in other heavy duty applications before they can be installed on aircraft.

On A330's, you still have diode-based rectifier units. Having no knowledge of what is the standard outside the aerospace, this is what I know and it's been in use since a long time. It's proven to work well.

When you have a system pulsating at 800hz, I can't help but wonder whether a recording system like the FDR can record a momentary surge lasting only one period of 0,00125 seconds or a few such periods. Such a short surge would not be large enough to make it to your frequency read-out anyway, and that's usually where the recording is taken.
Also what happens when you switch heavy users like the huge airco system on/off?

Dear airtechy, I am trying to keep everything in simple terms for everything to be understandable for everyone to follow. It's useless to throw a bunch of technical terms and to pretend to know something better, we're not talking about rocket science here, it's simple AC to DC conversion.

Don't you suspect that AC to DC conversion can yield impurities resulting in problems at the battery level?

I think aircraft are usually old technology as far as I have come near to it.
They do not follow modern technology because it is just too expensive to certify something new every year.

There is one exception, usually when they make a new type they take all the new stuff.

When you look at AC/DC, DC/DC converters and frequency controllers it is a new world.
Forget transformers, diode based rectifiers and banks of capacitors.
You do not need any longer shielded cables to run a variable frequency drive.
The converters pick the incoming wave into pieces and build with fast switching thyristors a new sine wave or a very clean DC.
This technology started really with computers and is there called a switching power supply.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 23, posted (1 year 7 months 2 days 5 hours ago) and read 26225 times:

I must be honest with you, I've never heard about Thyristors in an aaerospace context.


Regarding the B787, I found this:

Thales’s power conversion system has achieved a very high power density benchmark,
further contributing to reductions in both weight and volume onboard the B787. Lightweight
electrical circuits now replace some hydraulic circuits, meaning a greater range of systems
are now powered by electricity. For instance, the B787 features electrical brakes. The newgeneration power conversion system includes an innovative transformer and rectifier solution
that supports the B787 high-voltage DC network.
Boeing chose Thales’s lithium-ion battery technology, which provides higher reliability and
improved maintenance compared to traditional solutions, for the B787 low-voltage DC
emergency back-up subsystem. This is a first in civil aviation, with Thales as prime contractor
in association with Securaplane of the United States and GS Yuasa of Japan.

http://www.thalesgroup.com/Press_Rel...2010/20100119_-_PR_press_kit_B787/


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 24, posted (1 year 7 months 2 days 3 hours ago) and read 26218 times:

Well wisdom doesn't ask questions like these:

Quoting rcair1 (Reply 214):

Couple of questions:
- Can the RAT on the 787 start the APU?
- Can the main battery on the 787 start the APU?
- Are the 2 engines on the 787 (or any plane) considered 'independent'.
- Are the 2 alternators on each 787 engine/APU considered independent?

A RAT starting an APU... that's the best one. Are you an avionics engineer or just an electrics engineer?
If the RAT is starting the APU, who's going to power the flight controls and your essential bus? I doubt that starting the APU is anymore important than flying the airplane, or is it?

Can the main battery start the APU?
Of course the main battery can start the APU. There's no aircraft in the world that can't start an APU from the main battery. However, a separate APU battery is useful when you're dealing with larger APU's, so as to avoid purging huge capacities from your main batteries and also as a redundancy when you're dealing with an electrical failure. When you're running on your main batteries after an electrical failure, the last thing you want to do is to waste the little capacity you have on trying to start the APU.

Are the 2 engines considered independent? If you have experience working with aircraft, you should have gotten training about that, so why ask?

Are the 2 alternators on each 787 engine considered independent?
Except for general aviation aircraft and some military aircraft, in civil aviation we always speak about generators. On the B787 we also speak about generators. So why insist about "alternators"?

Something's fishy here.
Definitely not questions an avionics engineer would ask.


User currently offlineBoeingVista From Australia, joined Jan 2009, 1581 posts, RR: 3
Reply 25, posted (1 year 7 months 2 days 1 hour ago) and read 26501 times:

An ex NTSB board member thinks that the FAA is inappropriately using the Airworthy Directive system and should have pulled the 787's type certificate.

Quote:
I don’t question that a grounding of the 787 fleet was prudent and necessary in the interests of air safety. But I do question the use of an Emergency Airworthiness Directive to accomplish that grounding, when no fix is provided. There’s no inspection that’s mandated, no corrective action that needs to be taken. The action required is a marvel of government gobbledygook. Under the heading AD Requirements, it states: “[T]his AD requires modification of the battery system, or other actions, in accordance with a method approved by the manager, Seattle Aircraft Certification Office (ACO) FAA.” What does that mean when no method is provided?

What it means to me is that the FAA engaged in linguistic–if not legalistic–contortions to arrive at this method of grounding the fleet. In the process it basically made a sham of the airworthiness directive process. Why does that matter, you ask? Well, first, the government shouldn’t engage in legal contortions for one entity that it perhaps wouldn’t do for anyone else. Process matters, and treating everyone the same is a worthy government goal.

So what I deduce from this extreme stretching of the AD process is that the FAA was trying to ground the fleet without pulling the 787’s type certificate. I can understand that Boeing would have fought hard to keep the agency from pulling its type certificate. Clearly that would have impugned the aircraft and Boeing’s design and manufacturing far more than an Emergency Airworthiness Directive. But does that make it the right thing to do?
http://www.ainonline.com/aviation-ne...y-ad-inappropriate-case-boeing-787



BV
User currently offlinepar13del From Bahamas, joined Dec 2005, 7275 posts, RR: 8
Reply 26, posted (1 year 7 months 2 days 1 hour ago) and read 26332 times:

From the article:
It’s a lot easier to say that an AD has been complied with than to ensure that the requirements of a type certificate have been met.

Technically and legally yes, but since the AD is written in such vague terms, the goal post is not fixed in the ground, it's on the back of a flat bed, it's moveable.
Interesting article, its one technical issue which appears to have been overlooked - or at least I do not recall reading it - in the number of threads on the issue. Discussions have taken place on the certification process, so my next question would be, since the type certificate was not pulled, is the FAA limited in the amount of new certification they can demand from Boeing via an AD?


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 27, posted (1 year 7 months 2 days ago) and read 26738 times:

Quoting Wisdom (Reply 29):
A RAT starting an APU... that's the best one. Are you an avionics engineer or just an electrics engineer?
If the RAT is starting the APU, who's going to power the flight controls and your essential bus? I doubt that starting the APU is anymore important than flying the airplane, or is it?

The APU can be started by the APU battery with the assistance of the main battery. The front external or any engine generator can also provide power to the APU starters (one at a time)--the RAT can't start the APU.

Quoting Wisdom (Reply 29):
Can the main battery start the APU?
Of course the main battery can start the APU.

The Main battery can only assist the APU battery in starting the APU. If the APU battery is dead (or removed) your APU is inoperative--so NO the Main battery cannot start the APU by itself.


User currently offlineCaliAtenza From United States of America, joined Dec 2006, 1577 posts, RR: 0
Reply 28, posted (1 year 7 months 1 day 23 hours ago) and read 26611 times:

What about using batteries from a different supplier and testing those to see if the same problems occur? Im sure this has been brought up in the other threads, but i havent been following along, so forgive me.

User currently offlinesweair From Sweden, joined Nov 2011, 1824 posts, RR: 0
Reply 29, posted (1 year 7 months 1 day 18 hours ago) and read 26213 times:

So would swapping to the safe Li chemistry even satisfy the worst critics here? Or is the only way to satisfy them going the route of their favorite plane maker?

Will this always be the 3-4-3 of the 787 on this site?


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 30, posted (1 year 7 months 1 day 18 hours ago) and read 26185 times:

Quoting 7BOEING7 (Reply 32):
The Main battery can only assist the APU battery in starting the APU. If the APU battery is dead (or removed) your APU is inoperative--so NO the Main battery cannot start the APU by itself.

I know that very well.
The question was literally whether the main battery can start the APU, and the answer is yes.
The question was not whether the main battery can start the APU when the APU is inop.
No APU battery = APU inop = nothing can start it.

Quoting 7BOEING7 (Reply 32):
The APU can be started by the APU battery with the assistance of the main battery. The front external or any engine generator can also provide power to the APU starters (one at a time)--the RAT can't start the APU.

Explain that to RCAIR, you don't need to walk me through obvious stuff.
I've started plenty of APU's, on A320, A330, A340, B737, B747, B767, B777 and a range of RJ's.


User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2241 posts, RR: 5
Reply 31, posted (1 year 7 months 1 day 15 hours ago) and read 25872 times:

Quoting Wisdom (Reply 18):
The issue is not the voltage, as it will be around 115V, the issue is your huge current pulses.

Current pulses happen - by voltage pulses. There is no current pulse without a voltage pulse, that causes it (unless the load is higly capacitive). So the root cause would be voltage spikes. Current pulses without an increased voltage would mean load breakdowns (shortcuts).

Quoting Wisdom (Reply 22):
When you have a system pulsating at 800hz, I can't help but wonder whether a recording system like the FDR can record a momentary surge lasting only one period of 0,00125 seconds or a few such periods. Such a short surge would not be large enough to make it to your frequency read-out anyway, and that's usually where the recording is taken.

You are correct about the FDR, but don't you think that the during testing in the lab, where certainly any voltage and current has been monitored very thoroughly, such spikes would have been found and ironed out?

I agree, that the surrounding electrical system should not be ruled out from having contributed to the battery isues. I am not certain about the nature of the impact however. Current pulses would not be the primary suspect thing IMO in that regard.


User currently offline2175301 From United States of America, joined May 2007, 1072 posts, RR: 0
Reply 32, posted (1 year 7 months 1 day 13 hours ago) and read 25633 times:

Quoting Wisdom (Reply 22):
When you have a system pulsating at 800hz, I can't help but wonder whether a recording system like the FDR can record a momentary surge lasting only one period of 0,00125 seconds or a few such periods. Such a short surge would not be large enough to make it to your frequency read-out anyway, and that's usually where the recording is taken.
Also what happens when you switch heavy users like the huge airco system on/off?
Quoting rheinwaldner (Reply 37):

You are correct about the FDR, but don't you think that the during testing in the lab, where certainly any voltage and current has been monitored very thoroughly, such spikes would have been found and ironed out?

Not only would all of this been tested in the lab; Boeing (and all other Aircraft Mfrs) fly heavily instrumented test aircraft for many months to over a year specifically looking for these kinds of issues. Unexpected noise/pulses in the electrical system is always looked at due to its history of causing problems - and I'd be very surprised if the recording equipment did not record voltage (and current in various places) down to the micro-second (0.000001 s).

So while there might be a malfunctioning piece of equipment that generates spikes and surges; the base design would have been ensured to be free of unexpected/undesigned for spikes and surges through multiple rounds of flight testing and actuation of all the components and systems. I suspect that any malfunctioning equipment will give itself away by other means that are in fact readily detectable by the normal monitoring system.

Have a great day,


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 33, posted (1 year 7 months 1 day 12 hours ago) and read 25549 times:

I appreciate the last 2 posts. At least we are discussing rationally and constructively.
2175301, regarding the FDR, I read somewhere that due to a wiring issue on the NH aircraft, the FDR could not record voltage as accurately.

I found the article for you:


Masahiro Kudo, the JTSB's chief investigator, said at a separate briefing, that the unusual circuit wiring may

have affected the digital flight data recorder's measuring of voltage in the burned battery. He added that if affected, the voltage of the battery might have dropped to a lower level than shown by the flight data.
A more accurate voltage reading could be crucial in helping the JTSB make progress with its investigation, he added. The batteries under investigation come from an ANA 787 forced to make an emergency landing in western Japan on Jan. 16 with battery trouble.

User currently offline2175301 From United States of America, joined May 2007, 1072 posts, RR: 0
Reply 34, posted (1 year 7 months 1 day 11 hours ago) and read 25248 times:

Quoting Wisdom (Reply 39):

However, the batteries have a built in low voltage cut off to prevent damage (in this case I am defining the assembly of cells and control circuits within the "battery box" as the battery). So yes, while a wiring issue existed in that specific aircraft and the voltage the FDR "may" not be correct; That does not mean that the voltages were allowed to drop below the safe point for the battery. If the Battery voltage drops to low its own protective circuits lock out the battery - and the battery must be sent to a service center to be tested and have the protective circuits unlocked per discussions by people who work for Boeing in the early threads on this issue.

As far as you claim for rational discussion. It seems to me that you have posted several items that appear to be issues that are taught at about the 2nd or 3rd semester in a electrical engineering degree program (from the 1980's no less when I was in college); with the apparent claim that that stage of technology is what is in fact used in aircraft; and apparently that technology has never gotten beyond that (which makes me wonder if you even know what was taught in the 3rd and 4th year - much less at the graduate level).

My memory is that the diagram you posted at the end of post 18 on how simple AC/DC rectifier circuits work and potential problems is right out of a 2nd or 3rd semester EE textbook from the early 1980's. Also, it seems to me that you do not understand what goes into a test program to demonstrate that something works; or what kind of very common commercial/industrial electronics and test equipment has been on the market for decades (we had electronic micro-second "last 30 second" multichannel voltage & state recorders installed in a power plant that went online in 1983 - and it would spit out about 50 ft of a paper trace after a plant trip so that we could diagnose what happened first. These days they have eliminated the paper printout and you can download this info to a computer).

[Full disclosure here: I am actually a Mechanical Engineer (and a PE), but I specifically minored in control theory and implementation as it was very apparent from my working in power plants while in college how important controls were - and it turns out I am one class short of a EE minor, and one class short of a Math minor as well. I even got permission to take the graduate level EE/ME graduate controls lab where we analyzed how systems and control systems actually responded and built control circuits from scratch (or sub component assemblies) to be able to control processes and electrical devices. This included integrated controls for a multiple device system. I have spent much of my life working in power plants - and currently work in a nuclear power plant and I participate on industry committees in my area of expertise and a paper I wrote for the ASME Power conference last year was chosen as best paper in its technical section. I am one of the few people "Root Cause Investigator" Qualified at my plant - and the Root Cause Process in the nuclear industry is the same as what the NTSB uses to investigate transportation events].

So, while I do not work in the Aviation industry (although we have a few engineers in my nuke plant that came from aerospace). I see no reason to expect that the aviation industry would not be using the same kinds of technology and testing methods that are commonly used in other critical industries, and have been used for decades. I also understand how companies respond with different teams working on potential solutions when a Root Cause investigation is ongoing.

Overall, while I understand the purpose of a public forum. The mindless speculation by people who clearly have no clue as to how things work in real life and the kinds of standard technologies and approaches out there, and who wish to maintain what I perceive as their own extremist (and often ignorant positions) has been very painful to read.


Have a good day,


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 35, posted (1 year 7 months 1 day 6 hours ago) and read 24523 times:

Boeing engineers? Where? You mean those guys "sharing details" on why the FAA and the NTSB are wrong and that despite the safety factor, keeping the aircraft flying is more relevant? Sorry, I have no respect for that kind of attitude in an aviation context. In aviation, we look for causes before finding remedies.
In reality, I see that many people working in aerospace become so impressed by commercial pressure that they forget that their job is about safeguarding lives and delivering the best possible safety performance.

So I think that it's better for Boeing's sake that Boeing takes care of PR.


Mr 217, I have done no college but I've been through airline training programs.
Down here in Europe, only few colleges teach aerospace and even then, they touch a bit of this and a bit of that, you never go into depth in everything, there's just too much ground to cover.
You won't touch aviation subjects until way into the second year in college.

Even after school in the real life, you don't get to open an LRU. Most of the LRU overhauls are done in specialised overhaul shops where the LRU's are plugged in and tested.
The most you do in the field is a software update, a bite test or a removal/installation.

However, one thing we get to do and design engineers don't, is electrical troubleshooting on real aircraft and guess what? The most common issue on an electrical system is not a short-circuit; it's a bad grounding/earthing/bonding. Either contaminated, corroded or segregated from the fuselage. That's not something you learn at school, that's something you figure out after undoing thousands of panels and following hundreds of wires around the aircraft.

Whenever a battery is involved, depending on the failure condition, you just put a new one and monitor it.
If it fails soon after, you know that it's not the battery causing the issues.
When you replace a main battery prematurely, most of the times the failed battery doesn't see operation ever again. It's just cheaper to put a new one than to T/S the failed battery and to replace relevant components only. If it's just a scheduled overhaul, the battery goes into charging and voltages are measured, electrolyte levels are checked and refilled if necessary and the battery goes back into operation.


Given that the batteries didn't fail during lab tests, I'm eager to think that whatever could't accurately be depicted in a lab test is causing it. So there, I think that my troubleshooting experience is more relevant than an electrical engineer's point of view on how the system is so perfect it can't fail and only a battery quality problem is to blame.
I've seen "perfect" electrical systems fail for as little as a thin layer of dust or a little bit of moisture.

Wouldn't it be better for Boeing if the issue is outside the battery? It would just be a matter of modifying with off-the-shelf solutions, rather than redesigning the battery that may not even be the cause of the problems, but rather the consequence of another problem?

Am I an Airbus fan? My favorite aircraft is the B777 and the XWB is to me the ugliest aircraft I've ever seen. That should say enough.
BTW I think that Boeing is doing a marvelous job on the PR front, keeping their mouth shut with humility and trying to solve the issue. No one wants the B787 to remain stuck on the ground for longer than necessary, but everyone (except some marketing fanboys) expect it to be a safe and sound machine.

[Edited 2013-03-03 14:54:15]

User currently offlineRickNRoll From Afghanistan, joined Jan 2012, 841 posts, RR: 0
Reply 36, posted (1 year 7 months 1 day 5 hours ago) and read 24298 times:

Quoting ComeAndGo (Reply 42):
Keep in mind that the same "knowledgeable" contributors suggested the 787 shouldn't have been grounded in the first place.

I don't recall that they did. IIRC, they all take the incident seriously, but do object to speculation and bickering on the matter.


User currently offlinelightsaber From United States of America, joined Jan 2005, 13152 posts, RR: 100
Reply 37, posted (1 year 7 months 1 day 4 hours ago) and read 24293 times:
Support Airliners.net - become a First Class Member!

Quoting Wisdom (Reply 44):
, I see that many people working in aerospace become so impressed by commercial pressure that they forget that their job is about safeguarding lives and delivering the best possible safety performance.

Actually, engineers are about the last to bend to commercial pressure. A few? Sure. Now that the 787 has this much attention?   

The 787 will fly again and be safe. If the engineers had any sloppiness, we wouldn't have had the last 12 years of excellent safety.

Quoting Wisdom (Reply 44):
Given that the batteries didn't fail during lab tests, I'm eager to think that whatever could't accurately be depicted in a lab test is causing it. S

Too simplistic. A solution has to come from somewhere. We cannot turn back to being cavemen. That means using science and statistics to find a root cause and fix it. Even if no root cause is found, it is possible to design for fewer failures and better containment.

Remember, the requirement is not perfection. There is no perfection. As long as the 787 has a less than 10^-6 chance, it is good.

I worked for years in lab and flight test. Aircraft are far safer due to that work. We find things that are off (for example, found a fault in an aircraft ABS software once). A fault brought on by improved GPS capabilities. We find the faults and move on.

They've found the fault in the 787 fuel valves and will make the batteries safer.

You seem to have something against electrical aircraft. After a long time in flight test, I am convinced they are safer. For example, another team had an aircraft have a flap stick in flight. That made the aircraft unstable due to the half open position. In the past, that would have been a lost airframe. Not with today's aircraft.   

The 787 will fly again and be safe. I would fly on it in a heartbeat.

For in aircraft, one finds the order of problems is:
1. Pneumatic (gases)
2. Hydraulic (fluids)
3. Electrical
4. Software

Software is #4 because it is so tested. But once tested, make aircraft quite a bit safer than before. Ever seen an aircraft with "water hammer" in the control systems? It is a bear to fix in old school aircraft once flight testing has started. With electrical actuators perhaps powered by hydraulics, it is a little code change and the problem goes away.

Errors will be found in all new designs. But because of the fuel and maintenance savings, new designs will be done. And they are safer. For example, I would never want to go back to the time when rotor x-rays were only reviewed by humans. The computers find far more errors and thus save lives.

One slipped by. But no one was killed. Not even close. The FAA would let the fleet fly until its safe. Your arguments sound like some of my American compatriots who still won't fly the A320 due to that one crash into trees. OK, now that scenario is part of the system center lab testing.

The 787 will fly again with larger boxes for the batteries. While it might not fix the root cause, it does cut the probability of an issue. Reducing the probability is what is required.

Lightsaber



Societies that achieve a critical mass of ideas achieve self sustaining growth; others stagnate.
User currently offline777ER From New Zealand, joined Dec 2003, 12189 posts, RR: 18
Reply 38, posted (1 year 7 months 14 hours ago) and read 22063 times:
AIRLINERS.NET CREW
FORUM MODERATOR

Please remain on topic and not discussing what your job/qualification etc is.

This thread is for the discussion regarding the current grounding of the 787 fleet


User currently offlineseahawk From Germany, joined May 2005, 1069 posts, RR: 0
Reply 39, posted (1 year 7 months 14 hours ago) and read 21947 times:

I personaly think flying the aircraft needs to be done. Preferably the 2 that had the incidents and 2 others to cross check. If possible improve the monitoring of the battery pack and see what you come up with.

User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 40, posted (1 year 7 months 12 hours ago) and read 21679 times:

Quoting seahawk (Reply 40):

I personaly think flying the aircraft needs to be done. Preferably the 2 that had the incidents and 2 others to cross check.

News has gone dark on the fate of the JAL plane sitting at BOS. No updates on whether it is flyable as is, with just a new battery installed, or if Boeing or JAL has cleaned up from whatever fire damage there was. It didn't look too severe, so it seems odd there wouldn't be an update since the date of the fire on the fate of that particular plane.



International Homo of Mystery
User currently offlinercair1 From United States of America, joined Oct 2009, 1323 posts, RR: 52
Reply 41, posted (1 year 7 months 10 hours ago) and read 21260 times:
AIRLINERS.NET CREW
CUSTOMER SERVICE & SUPPORT

Internet is down - so I haven't looked at stuff in several days - and it will continue to be down for about a week. The price of living in the boonies. Have 1/2 hour of connection and I was amazed to see all the attacks continuing on my post. So I went back and re-read it (my post) since I've not been on line for a few days.

Indeed I made an error - it was not the error I'm accused of - but it is an error.

This line -

Quoting rcair1 (Reply 1):
The auto-transformer is the electrical equivalent of the constant speed mechanical drive in a traditional a/c system. Frankly - an auto-transformer is far more reliable.

should have said "The auto-transformer unit is the ...."

The loss of the word "unit" somewhere in the editing process has caused a lot of thrash. I should have seen the error and corrected it long ago - but you know how you sometimes read what you intend, not what you see.

What was intended as in informative post turned into a cause for thrashing and for that I offer my sincere apologies.  

Back into the black hole...



rcair1
User currently offlinelightsaber From United States of America, joined Jan 2005, 13152 posts, RR: 100
Reply 42, posted (1 year 7 months 10 hours ago) and read 21199 times:
Support Airliners.net - become a First Class Member!

We'll keep on topic.


And that topic is the need to get the 787s back flying. I agree with the suggestion that the two to fly are the ones that had issues. I have a feeling their wiring has been verified to the nth degree.

What I would like to know, not being a Li batter expert (they just worked, so why worry?), is:
1. How much does adding spacing/cooling help reduce the risk of a thermal runaway?
2. I understand the insulation will help stop a 2nd cell from 'running away,' but as a thermal management expert myself, I wonder how they are 'threading that needle.'
3. Any software changes (voltages, charging ramp, etc.?).

If anyone has a link to a leaked presentation, I'm curious.

Quoting rcair1 (Reply 41):
Back into the black hole...

Give bigfoot a hug from us all. I personally love backpacking. Partially to get out of cell phone range to remember life doesn't always involve internet bandwidth.  

Lightsaber



Societies that achieve a critical mass of ideas achieve self sustaining growth; others stagnate.
User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 43, posted (1 year 7 months 9 hours ago) and read 21001 times:

Boeing Airplane head Ray Conner sees no reason to adjust 787 delivery forecasts for 2013 -- gee, what a surprise. The corporate bubble world must be a wonderful place to be, so weird and wonderful.

"Conner said parent Boeing Co saw no reason to adjust its forecast for the number of 787 jets delivered this year. He spoke at an investor conference hosted by JPMorgan in New York."

http://www.reuters.com/article/2013/...oeing-conner-idUSL1N0BWBDL20130304


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 44, posted (1 year 7 months 8 hours ago) and read 20810 times:

Quoting ServantLeader (Reply 43):
Boeing Airplane head Ray Conner sees no reason to adjust 787 delivery forecasts for 2013 -- gee, what a surprise. The corporate bubble world must be a wonderful place to be, so weird and wonderful

Right now there is no reason to think differently. If, big if, the FAA buys off the fix and everything is wrapped up by June or July getting 60-70 airplanes delivered shouldn't be a problem. After what sounds like a quick fix for the battery is installed the B and C flights are all that's left to get all the built airplanes delivered to the customer. Right now that's all the information Ray Conner has to work with, if you know something he doesn't please enlighten us.


User currently offlineart From United Kingdom, joined Feb 2005, 3382 posts, RR: 1
Reply 45, posted (1 year 7 months 8 hours ago) and read 20777 times:

(Reuters) - Boeing Commercial Aircraft Chief Executive Ray Conner said the company is very confident about its proposed fix for batteries that melted down on two 787 Dreamliners in January, and the process of getting the fix installed and the plane flying again can move quickly once the solution is approved by regulators.

http://www.reuters.com/article/2013/...oeing-conner-idUSL1N0BWBDL20130304

Sorry, I've missed the proposed fix. What is it?


User currently offlineKarelXWB From Netherlands, joined Jul 2012, 11819 posts, RR: 33
Reply 46, posted (1 year 7 months 8 hours ago) and read 20761 times:

Quoting art (Reply 45):
Sorry, I've missed the proposed fix. What is it?

See http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_02_28_2013_p0-554228.xml



Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineBestWestern From Hong Kong, joined Sep 2000, 7162 posts, RR: 57
Reply 47, posted (1 year 7 months 7 hours ago) and read 20519 times:

Quoting ServantLeader (Reply 43):
Boeing Airplane head Ray Conner sees no reason to adjust 787 delivery forecasts for 2013 -- gee, what a surprise. The corporate bubble world must be a wonderful place to be, so weird and wonderful.

"Conner said parent Boeing Co saw no reason to adjust its forecast for the number of 787 jets delivered this year. He spoke at an investor conference hosted by JPMorgan in New York."

Just like they saw no reason to adjust the original first flight schedule. This is corporate governance at it's worst.



The world is really getting smaller these days
User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 48, posted (1 year 7 months 6 hours ago) and read 20263 times:

Quoting lightsaber (Reply 42):
And that topic is the need to get the 787s back flying. I agree with the suggestion that the two to fly are the ones that had issues. I have a feeling their wiring has been verified to the nth degree.

You could fly the ANA B 787 again in unchanged condition, new battery of course.

In case of the Boston JAL, she will hardly fly but everything being replaced in the EE bay.
That would be common practice after such a fire.

What they rip out they can test of course on the ground in a laboratory.


User currently offlinepar13del From Bahamas, joined Dec 2005, 7275 posts, RR: 8
Reply 49, posted (1 year 7 months 5 hours ago) and read 20132 times:

Quoting BestWestern (Reply 47):
Just like they saw no reason to adjust the original first flight schedule. This is corporate governance at it's worst.

I would agree that was, this as in now is different.
As of today, they are:
1. Continuing to build 787 as per schedule
2. Ramp up production to meet previously agreed schedule

As of today, we know that the grounding of the 787:
1. Will be lifted ?????

As of today I do not know if Boeing is hiring additional test pilots to have more a/c being tested at once.

So on the 04th March 2013 would it be responsible for them to say that Boeing is confident that they will deliver no a/c this year because the 787 will be grounded thru 2014, he is giving best case scenario based on existing information available to him, can we expect less or demand more?

A point is coming where based on flight testing requirements it will be physically impossible to deliver 60-70 a/c in 2013.
Boeing may have storage space for 60-70 a/c hence at this stage that figure is unaffected by the lack of deliveries.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 50, posted (1 year 7 months 3 hours ago) and read 19904 times:

Quoting par13del (Reply 49):
As of today I do not know if Boeing is hiring additional test pilots to have more a/c being tested at once.

They've got plenty of pilots to handle the load, any hiring they do would not be related to getting all the battery delayed airplanes out the door.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 51, posted (1 year 7 months 3 hours ago) and read 19852 times:

Quoting par13del (Reply 49):
A point is coming where based on flight testing requirements it will be physically impossible to deliver 60-70 a/c in 2013.

The airplanes they were delivering just prior to the grounding were going out the door with fewer flights than the first half of last year. December saw 12 deliveries with 6 first flighting and delivering that month (KPAE) -- really only flying the first 3 weeks -- half of them going from B-1 to C-1 in a week or less. When money is at stake miracles happen -- as long as deliveries started again by August, I could see them hitting 60, possibly more.


User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 52, posted (1 year 7 months 2 hours ago) and read 19959 times:

Quoting 7BOEING7 (Reply 44):
Right now there is no reason to think differently.

Boeing's credibility on the 787 program says otherwise. Of course Conner needs to deliver the company line that all's well and move along folks nothing to see here; that's his job as stock price buoy. Based on their track record I'd be shocked if even half of what he claims comes to be.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 53, posted (1 year 7 months 1 hour ago) and read 19766 times:

Quoting ServantLeader (Reply 53):
Boeing's credibility on the 787 program says otherwise. Of course Conner needs to deliver the company line that all's well and move along folks nothing to see here; that's his job as stock price buoy. Based on their track record I'd be shocked if even half of what he claims comes to be.

Their past credibility does have some issues but if the grounding is lifted in the next couple of months he'll be proven correct.


User currently offlinePlanesNTrains From United States of America, joined Feb 2005, 5590 posts, RR: 29
Reply 54, posted (1 year 6 months 4 weeks 1 day 23 hours ago) and read 19514 times:

Quoting BestWestern (Reply 47):
Just like they saw no reason to adjust the original first flight schedule. This is corporate governance at it's worst.

I guess I'm not clear on what you want him to say. "Gee, we have no clue what to expect"? "We won't deliver planes this year"?

If the only information they have right now is that a near-term fix will allow them to get the deliveries out the door, why should he lie and say otherwise?

Quoting ServantLeader (Reply 53):
Boeing's credibility on the 787 program says otherwise. Of course Conner needs to deliver the company line that all's well and move along folks nothing to see here; that's his job as stock price buoy. Based on their track record I'd be shocked if even half of what he claims comes to be.

Well, that's all nice and all, and we understand your point of view in regards to Boeing, but unless you have anything else to add, why not sit back now and see if your predictions come true?

-Dave



Next Trip: SEA-ABQ-SEA on Alaska
User currently offlinepacksonflight From Iceland, joined Jan 2010, 381 posts, RR: 0
Reply 55, posted (1 year 6 months 4 weeks 1 day 20 hours ago) and read 19193 times:

Quoting ServantLeader (Reply 52):
Boeing's credibility on the 787 program says otherwise. Of course Conner needs to deliver the company line that all's well and move along folks nothing to see here; that's his job as stock price buoy. Based on their track record I'd be shocked if even half of what he claims comes to be.

This statement from Conner is a bit funny: "It is important to recognize that batteries are not used in flight." But still there was an in flight diversion because of battery fire...

His statement could be applied to live vests as well, they are not needed in flight.


User currently offlineB777LRF From Luxembourg, joined Nov 2008, 1367 posts, RR: 3
Reply 56, posted (1 year 6 months 4 weeks 1 day 14 hours ago) and read 18579 times:

Quoting packsonflight (Reply 55):
His statement could be applied to live vests as well, they are not needed in flight.

Or, strictly speaking, the landing gear.

I agree with those who say Connor couldn't really say anything apart from what he did, but I do have this sneaking suspicion it may come back to haunt him. That is to say, I am not at all convinced Boeing will deliver on their forecast of 60-70 this year. In fact I fear the sum total may amount to zero, but that's the eternal pessimist in me speaking, fueled as it is by the countless statements Boeing has made about the 787 over the years which have later proved to be incorrect.



From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 350 posts, RR: 0
Reply 57, posted (1 year 6 months 4 weeks 1 day 14 hours ago) and read 18502 times:

I'm surprised so far in all these threads, no-one has asked "Is there a doctor in the house?".

Where's Doctor X when you need one?

His posts of some years ago were, to say the least, provocative! Accurate?? Predictive??


User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 58, posted (1 year 6 months 4 weeks 1 day 14 hours ago) and read 18495 times:
Support Airliners.net - become a First Class Member!

Quoting B777LRF (Reply 56):
That is to say, I am not at all convinced Boeing will deliver on their forecast of 60-70 this year.

I'm confident Boeing will assemble 60-70 787s this year. Whether regulatory authorities will allow them to deliver that many is another story...




Quoting Sassiciai (Reply 57):
Where's Doctor X when you need one?

You mean Captain X. And his opinion was ZA001 would crash on it's first flight, so yeah, he's clearly prescient.  


User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 350 posts, RR: 0
Reply 59, posted (1 year 6 months 4 weeks 1 day 13 hours ago) and read 18379 times:

Captain X - indeed, thanks for the correction! It was a few years ago!

Maybe a Doctor X would be more useful now, with the current issues, as the engineers, scientists, et al are having an up-hill struggle at present to find the problem!


User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 60, posted (1 year 6 months 4 weeks 1 day 13 hours ago) and read 18232 times:

Quoting packsonflight (Reply 55):
This statement from Conner is a bit funny: "It is important to recognize that batteries are not used in flight."

But apparently a functioning APU battery is required for the APU to operate, so if the APU is running in flight then the APU battery is being used. Conner may have meant to say that the batteries don't normally perform a flight critical function (he did say he was jet lagged).

Quoting packsonflight (Reply 55):
His statement could be applied to live vests as well, they are not needed in flight.

And they don't have any tendency periodically to go up in smoke either.  


User currently offlinekanban From United States of America, joined Jan 2008, 3575 posts, RR: 27
Reply 61, posted (1 year 6 months 4 weeks 1 day 12 hours ago) and read 18014 times:
Support Airliners.net - become a First Class Member!

Quoting hivue (Reply 63):
But apparently a functioning APU battery is required for the APU to operate, so if the APU is running in flight then the APU battery is being used. Conner may have meant to say that the batteries don't normally perform a flight critical function (he did say he was jet lagged).

I believe we've covered this ad nausium.. the battery is required to start the APU.. and no current is drawn once started.


User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 350 posts, RR: 0
Reply 62, posted (1 year 6 months 4 weeks 1 day 12 hours ago) and read 17937 times:

I thought that this thread was beginning to raise its head from the dire details and opinions about batteries, something that has dragged on for almost all these 12 posts (ad nausiam, as from Kanban just above). Maybe 200+ posts per thread, but now with a significantly diminishing list of participants! Please, let's now wait for real news, all you speculators are done with anything fresh, and all the rest of us must be bored with the "ad nausiam" and circular speculation (based on my own reaction) about batteries!

Attempts to open threads about the impact on (ex)-current and future operators of the 787 in the last 2 weeks were cancelled, with the moderators wishing to keep it all in one 787-subject thread! At that time, there were only posts about battery technology, so now I see a discussion about the impact of grounding on airlines! Much better, more relevant, and more interesting!

May I ask the battery guys to continue elsewhere "tech/ops"?, and leave this thread clear for "civil aviation"!


User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2241 posts, RR: 5
Reply 63, posted (1 year 6 months 4 weeks 1 day 11 hours ago) and read 17896 times:

Quoting PanAmPaul (Reply 60):
move "really fast"

That is not the point I would stress in Boeings position. Move "really carefull" is the impression the world needs to get. They can have quick progress anyway, but nobody should have interest in a hastened resolution...

"Moving fast" is the recipe to overlook important details. And too much has been overlooked in the 787 program in the past.


User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 64, posted (1 year 6 months 4 weeks 1 day 11 hours ago) and read 17758 times:

Quoting PanAmPaul (Reply 60):
Ray Conner spoke in New York yesterday, saying that the company would move "really fast" to get the Dreamliner back in the air following FAA certification plan approval.

I wonder how much longer it will take the FAA to review and approve Boeing's proposal. According to the article from FlightGlobal last week, we should have heard something by yesterday:

Boeing to present 787 interim solution to customers

Quote:
The meeting with customers comes after Boeing presented an interim solution to the US Federal Aviation Administration's head Michael Huerta and deputy transportation secretary John Porcari on 22 February.

Under their plan, which the FAA is expected to respond to - and most likely approve - on Monday, 4 March 2013, the 787 could resume operational service as early as late March.



International Homo of Mystery
User currently offlineKarelXWB From Netherlands, joined Jul 2012, 11819 posts, RR: 33
Reply 65, posted (1 year 6 months 4 weeks 1 day 11 hours ago) and read 17731 times:

The FAA will probably wait until the NTSB release their report on the JAL fire.


Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 66, posted (1 year 6 months 4 weeks 1 day 10 hours ago) and read 17764 times:

Quoting KarelXWB (Reply 68):
The FAA will probably wait until the NTSB release their report on the JAL fire.

That could be months and months. The optimism of the Boeing executives quoted above makes me believe there'll be an interim solution approved.



International Homo of Mystery
User currently offlineKarelXWB From Netherlands, joined Jul 2012, 11819 posts, RR: 33
Reply 67, posted (1 year 6 months 4 weeks 1 day 10 hours ago) and read 17722 times:

Quoting AeroWesty (Reply 69):
That could be months and months.

Sorry, I did not mean the full report. The NTSB will probably release a preliminary report due this (or next) week and the FAA might take a decision based on this report.

[Edited 2013-03-05 10:05:52]


Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 68, posted (1 year 6 months 4 weeks 1 day 10 hours ago) and read 17692 times:

Quoting KarelXWB (Reply 70):
The NTSB will probably release a preliminary report due this (or next) week

That's what I was wondering. I hadn't seen anything published anywhere other than the limited information in the FlightGlobal article.



International Homo of Mystery
User currently offlineKarelXWB From Netherlands, joined Jul 2012, 11819 posts, RR: 33
Reply 69, posted (1 year 6 months 4 weeks 1 day 10 hours ago) and read 17702 times:

Quoting AeroWesty (Reply 71):
anywhere other

There is some information available on http://leehamnews.wordpress.com/2013...-preliminary-report-due-this-week/



Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 70, posted (1 year 6 months 4 weeks 1 day 9 hours ago) and read 17570 times:
Support Airliners.net - become a First Class Member!

Leeam.net also notes that Boeing is likely following a similar path that Cessna has done for the lithium-ion batteries that are planned for use on Citation business jets. The Seattle Times ran an article about this on 29 January.

Quote:
The new battery for Cessna’s Citation jets is scheduled to fly within months and to be certified by the Federal Aviation Administration (FAA) this year.

A video shows what happened when engineers disabled all the battery’s protective systems, overcharged it and then deliberately ignited the hot chemicals: Nothing more than a few wisps of smoke puffed out of the battery box.


[Edited 2013-03-05 11:15:49]

User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 71, posted (1 year 6 months 4 weeks 1 day 9 hours ago) and read 17433 times:

I would love to see the weight versus safety trade study that so convinced Boeing that Li-ion was the slam dunk choice over Ni-cad -- how did such a marginal weight advantage so easily trump inherent volatility and the Ceasna situation?

User currently offlinescbriml From United Kingdom, joined Jul 2003, 12569 posts, RR: 46
Reply 72, posted (1 year 6 months 4 weeks 1 day 5 hours ago) and read 16999 times:
Support Airliners.net - become a First Class Member!

Quoting AeroWesty (Reply 69):
The optimism of the Boeing executives quoted above makes me believe there'll be an interim solution approved.

Boeing themselves have made it clear, there is no "interim solution". Boeing only has one solution. There is no plan B. If the FAA doesn't approve it, Boeing is stuffed.



Time flies like an arrow, but fruit flies like a banana!
User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 73, posted (1 year 6 months 4 weeks 1 day 5 hours ago) and read 16987 times:

Quoting scbriml (Reply 75):
Boeing themselves have made it clear, there is no "interim solution".

You're correct, I should have been more clear. I was talking in terms of waiting for the final NTSB report above. If there are any further recommendations made when the report eventually makes its way to the FAA, which the FAA decides to pick up, they'll be dealt with then. It won't be necessary to wait a year or more with planes on the ground before an approved solution can be installed.



International Homo of Mystery
User currently offlineAesma From France, joined Nov 2009, 6688 posts, RR: 12
Reply 74, posted (1 year 6 months 4 weeks 1 day 4 hours ago) and read 16969 times:

Quoting scbriml (Reply 75):
Boeing themselves have made it clear, there is no "interim solution". Boeing only has one solution. There is no plan B. If the FAA doesn't approve it, Boeing is stuffed.

Yes and no. Interim means that at some point a new battery with a new chemistry will be designed and certified for the 787, and I expect that to happen regardless. Meanwhile the 787 will fly with the current battery and its certification, with enough modifications for the FAA to approve it.



New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 75, posted (1 year 6 months 4 weeks 1 day 1 hour ago) and read 16691 times:

Quoting ServantLeader (Reply 74):
I would love to see the weight versus safety trade study that so convinced Boeing that Li-ion was the slam dunk choice over Ni-cad

In the Boeing video linked to in previous parts of this thread Mike Sinnett maintains that the reason Li-Ion was chosen over NiCad was not weight but power requirements: primarily starting the APU and braking in the case of loss of all other power sources.


User currently offlineseahawk From Germany, joined May 2005, 1069 posts, RR: 0
Reply 76, posted (1 year 6 months 4 weeks 21 hours ago) and read 16392 times:

I wonder how the new solution will appeal to the FAA and the customers, as it seems to be designed to only handle a battery failure, not to avoid it. If a a failed battery, although failed with a thermal event, still means that the plane has to divert for a safety landing, customers and the NTSB / FAA might not be too happy.

User currently offlinepacksonflight From Iceland, joined Jan 2010, 381 posts, RR: 0
Reply 77, posted (1 year 6 months 4 weeks 20 hours ago) and read 16209 times:

Quoting scbriml (Reply 75):
Boeing themselves have made it clear, there is no "interim solution". Boeing only has one solution. There is no plan B. If the FAA doesn't approve it, Boeing is stuffed.

That is only the official story. They can not propose plan A and simultainously say they are working on plan B because plan A is a crap.

I am sure that now Boeing has a team of engineers working on a soulution to have a plan B ready if the current proposal gets rejected by the FAA, they simply must be. If not Boeing is seriously complacent.


Anyway the NTSB interim report due any day now must be pretty good indicator how this is going to unfold.


User currently offlinegulfstream650 From United Kingdom, joined Mar 2008, 538 posts, RR: 0
Reply 78, posted (1 year 6 months 4 weeks 12 hours ago) and read 15502 times:

Quoting seahawk (Reply 79):

Exactly. There seems to be acceptance that the failure is likely to continue to happen. With only 50 aircraft delivered, and as many failures as there have been it doesn't really seem as though the future is bright as things stand at the moment.



I don't proclaim to be the best pilot in the world but I'm safe
User currently offlineAesma From France, joined Nov 2009, 6688 posts, RR: 12
Reply 79, posted (1 year 6 months 4 weeks 12 hours ago) and read 15471 times:

Quoting hivue (Reply 78):
In the Boeing video linked to in previous parts of this thread Mike Sinnett maintains that the reason Li-Ion was chosen over NiCad was not weight but power requirements: primarily starting the APU and braking in the case of loss of all other power sources.

That's playing with words. Any common type of battery can meet these requirements, even a lead-acid one, it would just be very big and heavy.



New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 80, posted (1 year 6 months 4 weeks 12 hours ago) and read 15420 times:

Quoting hivue (Reply 78):
In the Boeing video linked to in previous parts of this thread Mike Sinnett maintains that the reason Li-Ion was chosen over NiCad was not weight but power requirements: primarily starting the APU and braking in the case of loss of all other power sources.

I'm certain there was a laundry list of factors that played into the trade study, capacity, size, weight, safety, maintenance, cost... The point I'm making is that Boeing somehow determined that Li-oin was the clear choice, i.e. no close second, and they continue to sign its praises even in the midst of a crisis where it is at the epicenter -- color me baffled.

[Edited 2013-03-06 08:26:10]

User currently offlineRheinbote From Germany, joined May 2006, 1968 posts, RR: 53
Reply 81, posted (1 year 6 months 4 weeks 9 hours ago) and read 14886 times:

Circuits burned on ANA planes last year, Union says
http://www.bloomberg.com/news/2013-0...a-planes-last-year-union-says.html

A new twist. May or may not be connected with the battery incidents


User currently offlinesonomaflyer From United States of America, joined Apr 2010, 1817 posts, RR: 0
Reply 82, posted (1 year 6 months 4 weeks 9 hours ago) and read 14800 times:
Support Airliners.net - become a First Class Member!

Quoting Rheinbote (Reply 87):

Circuits burned on ANA planes last year, Union says
http://www.bloomberg.com/news/2013-0...a-planes-last-year-union-says.html

A new twist. May or may not be connected with the battery incidents

It would be interesting to know if these "circuit boards" are the same as the panel which caused the UA divert. We've heard allegations of substandard materials/parts going into those panels but there are circuit boards all over the place so some clarity as to which ones were involved would be helpful.


User currently offlinesonomaflyer From United States of America, joined Apr 2010, 1817 posts, RR: 0
Reply 83, posted (1 year 6 months 4 weeks 9 hours ago) and read 14675 times:
Support Airliners.net - become a First Class Member!

Quoting Aesma (Reply 90):
In fact Airbus already answered the question by going back to NiCad from a Li-Ion design, with a weight impact.

However the Airbus design is not the same as the 787 and the decision to switch battery technologies has far less impact on the 350 program than the 787 program. Airbus took what sounds like a more conservative approach when it came to introducing new technologies.

Recall the 787 has electric brakes, bleedless engines, a different and more powerful APU design, electric brakes etc. The power requirements for the 787 battery appear bigger than the 350.

Airbus was smart to simply say, "peace out!" They avoided the whole issue by switching battery technologies at little cost to their design. It's not nearly that simple with the 787 given the power requirements and the fact the a/c is flying and in full production.


User currently offlineBEG2IAH From United States of America, joined Apr 2004, 972 posts, RR: 18
Reply 84, posted (1 year 6 months 4 weeks 8 hours ago) and read 14591 times:
Support Airliners.net - become a First Class Member!

Quoting sonomaflyer (Reply 92):
Recall the 787 has electric brakes

Electric brakes are not new and are not unique to B787.

http://www.safran-group.com/site-saf...n-electric-brake-scores-world?3270

Excerpt: Electric brakes offer several advantages, including faster installation on the aircraft, more efficient monitoring of brake wear, higher dispatch reliability for the aircraft and simplified maintenance.



FAA killed the purpose of my old signature: Use of approved electronic devices is now permitted.
User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 85, posted (1 year 6 months 4 weeks 8 hours ago) and read 14551 times:

Quoting hivue (Reply 89):
Li-Ion has put the 787 AOG for weeks now. If it was as simple as swapping out Li-Ion for NiCad, from a business standpoint (i.e., trying to make money) Boeing probably would do it in a flash.

Going to NiCad would mean a complete redesign and 12-18 months to complete and re-everything -- Boeing has little choice but to play the Li-ion hand they dealt themselves until they run out of chips to avoid that scenario. The problem with that strategy is that it is highly probable that the FAA will reject the ironclad containment approach as fundamentally unsafe, which will force Boeing to go the NiCad route, which pushes the 12-18 schedule to the right by several months. If I were running Boeing I would drop Li-ion like a enflamed potato and get on with it.


User currently offlinenomadd22 From United States of America, joined Feb 2008, 1871 posts, RR: 0
Reply 86, posted (1 year 6 months 4 weeks 8 hours ago) and read 14508 times:

I just disposed of a smoking nicad battery. Nicads can and do run away just like lithiums. They just don't get the same press.


Andy Goetsch
User currently offlineJHwk From United States of America, joined Jan 2013, 236 posts, RR: 0
Reply 87, posted (1 year 6 months 4 weeks 8 hours ago) and read 14501 times:

Quoting BEG2IAH (Reply 93):
Electric brakes are not new and are not unique to B787.

http://www.safran-group.com/site-saf...?3270

The article you linked specifically states that the first tests were in 2008, the test aircraft was an A340, and the 787 will be the first production aircraft with them installed.

The technology might not be something new, but it is new to a commercial airliner and has an impact on the electrical design.


User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 350 posts, RR: 0
Reply 88, posted (1 year 6 months 4 weeks 8 hours ago) and read 14492 times:

About the electric brakes - with a cascade of failures, engines out, generators out, battery used to start APU, APU now out, RAT deployed, .........

How much energy do these batteries need to have/retain to provide enough energy to brake the aircraft on landing?


User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 89, posted (1 year 6 months 4 weeks 8 hours ago) and read 14412 times:
Support Airliners.net - become a First Class Member!

Quoting ServantLeader (Reply 94):
The problem with that strategy is that it is highly probable that the FAA will reject the ironclad containment approach as fundamentally unsafe...

I'm inclined to believe they will not take such a course of action. They have given no indication to Boeing that they will disallow Li-Ion batteries on aircraft and in fact are working with Cessna to certify them for the Citation family of business jets.

The FAA knew that even with the Special Conditions, the batteries could catch fire and/or leak electrolyte, which is why they required some form of containment for the cells in 2007 when they published the Special Conditions. That is why they worked with battery and aerospace companies - including Boeing - to develop a tougher standard known as RTCA DO-311 that went into effect in 2011. Of the many tests RTCA DO-311 requires, one includes turning off all failsafe electronics, short-circuiting the battery and watching for flames for three hours.

The 787 was not required to comply with RTCA DO-311, however I would not be surprised (and would personally prefer that) if whatever change Boeing offers would have to comply to RTCA DO-311.


User currently offlineBEG2IAH From United States of America, joined Apr 2004, 972 posts, RR: 18
Reply 90, posted (1 year 6 months 4 weeks 7 hours ago) and read 14199 times:
Support Airliners.net - become a First Class Member!

Quoting JHwk (Reply 96):
The article you linked specifically states that [...] the 787 will be the first production aircraft with them installed.

The article states this: "Messier-Bugatti was also selected to design and develop the electric brakes for Boeing's new 787 Dreamliner, scheduled to enter service in early 2009." The first production aircraft is not B787, but Grumman's Global Hawk using Goodrich electric brakes. Bombardier also tested Meggitt's EBrake in October 2008. New Eurocopter X4 will have electric brakes.

We can call this new technology, but Goodrich tested electric brakes back in 2005, Safran did in 2008 (but launched the program in 2003).

I had a chance to chat with Messier-Bugatti folks and get my hands dirty from one of those brakes. They were pretty confident electric brakes are the future.

[Edited 2013-03-06 14:03:00]


FAA killed the purpose of my old signature: Use of approved electronic devices is now permitted.
User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 91, posted (1 year 6 months 4 weeks 7 hours ago) and read 14195 times:

“We can’t say if there was any connection between the circuit boards and the battery, but there have been lots of problems with the electrical system,” Kazuo Harigai, assistant secretary of the Japanese aviation workers’ union, said at the press conference today.

http://www.bloomberg.com/news/2013-0...a-planes-last-year-union-says.html

When I read stuff like this, it's clear to me that there is a fundamental issue with the electrical system.
In my experience, electric problems are not uncommon, nor are they common. I think that if so many issues were noted, at least an analysis of each of these issues would be in their place to see if there is a common factor.

It's also clear that many things that worked fine in the labs are not working properly in service.
That means that either the tests didn't replicate actual operating conditions or actual operating conditions are different from the assumptions on which the tests are based.

In the meanwhile all B787's are safe and sound on the ground. I hope it stays that way until the issues are uncovered and fixed, instead of hurrying the thing back into the air and hearing very bad news over the radio.
After such a mediatised grounding, a crash could bring even a giant like Boeing into big trouble.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 92, posted (1 year 6 months 4 weeks 7 hours ago) and read 14117 times:

Quoting Sassiciai (Reply 97):
How much energy do these batteries need to have/retain to provide enough energy to brake the aircraft on landing?

If the thrust reversers are working and you have a fairly long runway (KMWH 32R 13500') you don't even need brakes.(However, if with all the other problems you've had to so far it's probably not your day and the only runway insight is only 5000' long.)


User currently offlineKarelXWB From Netherlands, joined Jul 2012, 11819 posts, RR: 33
Reply 93, posted (1 year 6 months 4 weeks 6 hours ago) and read 14105 times:

The NTSB just tweeted:

Quote:
NTSB to issue interim factual report on JAL B-787 battery fire investigation at 11 am ET on 3/7/13. Will post on http://go.usa.gov/4K4J
http://twitter.com/NTSB/status/309423495530565633



Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlinesonomaflyer From United States of America, joined Apr 2010, 1817 posts, RR: 0
Reply 94, posted (1 year 6 months 4 weeks 6 hours ago) and read 14001 times:
Support Airliners.net - become a First Class Member!

Quoting BEG2IAH (Reply 99):
The article states this: "Messier-Bugatti was also selected to design and develop the electric brakes for Boeing's new 787 Dreamliner, scheduled to enter service in early 2009." The first production aircraft is not B787, but Grumman's Global Hawk using Goodrich electric brakes. Bombardier also tested Meggitt's EBrake in October 2008. New Eurocopter X4 will have electric brakes.

We can call this new technology, but Goodrich tested electric brakes back in 2005, Safran did in 2008 (but launched the program in 2003).

I had a chance to chat with Messier-Bugatti folks and get my hands dirty from one of those brakes. They were pretty confident electric brakes are the future.

The Global Hawk is an unmanned drone, not a jetliner certified to carry human beings. The differences are substantial and the certification process different. No other airliner out there currently has this type of braking system. It does appear the same companies are developing the 350 series brakes as well (SAFRAN/Messier-Bugatti). I didn't see from a cursory check whether the 350 braking system is all electric or more of a conventional design.

The heavy electric demands made by the 787 design are new in the civilian aircraft industry. Combine that with the electric braking system, bleedless engines and the requirement that the battery must be able to power those brakes in the event of engine failure pointed the way for a powerful battery which was still relatively compact. This is where Boeing chose the Thales power system and the battery which is now at issue.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1452 posts, RR: 2
Reply 95, posted (1 year 6 months 4 weeks 6 hours ago) and read 14015 times:

I think it is just hype all about how impossible it is for Boeing to switch to Ni/Cad.
I bet they have a team working on it.

But is the reliability of the current battery the issue?
The problem is we do not know. We do not know the root cause.

We only know that two batteries went off, and they are dangerous in that condition, we do not know why.

It would be the joke to switch batteries only to find out that it was an electrical glitch.

So I believe, that a good containment, removing therefore the main danger, should get the B 787 in the air again.
Meanwhile Boeing will have a look at the electrics and the battery.


User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 96, posted (1 year 6 months 4 weeks 6 hours ago) and read 13998 times:

Quoting KarelXWB (Reply 102):
The NTSB just tweeted:

Hopefully there'll be some pearls of wisdom tomorrow which the FAA may use in determining whether to approve the fix Boeing presented last week.



International Homo of Mystery
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 97, posted (1 year 6 months 4 weeks 5 hours ago) and read 13987 times:

Quoting sonomaflyer (Reply 103):
the requirement that the battery must be able to power those brakes in the event of engine failure

I believe the battery only powers the brakes when you're down to RAT power only -- not a simple engine failure


User currently offlinesonomaflyer From United States of America, joined Apr 2010, 1817 posts, RR: 0
Reply 98, posted (1 year 6 months 4 weeks 5 hours ago) and read 13989 times:
Support Airliners.net - become a First Class Member!

Quoting 7BOEING7 (Reply 106):

Quoting sonomaflyer (Reply 103):
the requirement that the battery must be able to power those brakes in the event of engine failure

I believe the battery only powers the brakes when you're down to RAT power only -- not a simple engine failure

Once the aircraft lands, the RAT becomes ineffective and the FAA required the battery be able to power the electric brakes to full stop the aircraft. The RAT would be deployed from the time of dual engine failure until at/near touchdown thus saving up the battery for braking upon landing.


User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 99, posted (1 year 6 months 4 weeks 5 hours ago) and read 14128 times:

My question is even if the FAA approves Boeing's proposed solution, is there a possibility that some airlines (especially the Japanese carriers) and pilot / crew unions may refuse to fly until the root cause is found and fixed? What are the odds of that happening?

User currently offlineBEG2IAH From United States of America, joined Apr 2004, 972 posts, RR: 18
Reply 100, posted (1 year 6 months 4 weeks 4 hours ago) and read 13954 times:
Support Airliners.net - become a First Class Member!

Quoting sonomaflyer (Reply 103):
The Global Hawk is an unmanned drone, not a jetliner certified to carry human beings. The differences are substantial and the certification process different. No other airliner out there currently has this type of braking system. It does appear the same companies are developing the 350 series brakes as well (SAFRAN/Messier-Bugatti). I didn't see from a cursory check whether the 350 braking system is all electric or more of a conventional design.

But B787 is certified to carry human beings. It flew thousands of hours and landed thousands of times. I'm not sure how this battery issue makes all technologies implemented on the B787 inherently dangerous. This is slowly getting out of control. I'm also not sure users of Global Hawk would be happy if their very expensive and classified toys were unable to stop on a regular basis.

A350 will have hydraulic brakes from what I've seen.



FAA killed the purpose of my old signature: Use of approved electronic devices is now permitted.
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 101, posted (1 year 6 months 4 weeks 4 hours ago) and read 13942 times:

Quoting sonomaflyer (Reply 107):
Quoting 7BOEING7 (Reply 106):
Quoting sonomaflyer (Reply 103):
the requirement that the battery must be able to power those brakes in the event of engine failure

I believe the battery only powers the brakes when you're down to RAT power only -- not a simple engine failure
Once the aircraft lands, the RAT becomes ineffective and the FAA required the battery be able to power the electric brakes to full stop the aircraft. The RAT would be deployed from the time of dual engine failure until at/near touchdown thus saving up the battery for braking upon landing.

Okay, I guess by "an engine failure" you meant dual engine failure, however, if the APU is available I believe that would provide power to the brakes or did you mean dual engine failure and the APU won't start?


User currently offlineAngMoh From Singapore, joined Nov 2011, 488 posts, RR: 0
Reply 102, posted (1 year 6 months 4 weeks 4 hours ago) and read 13949 times:

Quoting Stitch (Reply 91):
They do have a choice, but it's a choice that will likely result in significant delays to the program returning to service.
Quoting ServantLeader (Reply 94):
Going to NiCad would mean a complete redesign and 12-18 months to complete and re-everything -- Boeing has little choice but to play the Li-ion hand they dealt themselves until they run out of chips to avoid that scenario.
Quoting Stitch (Reply 98):
I'm inclined to believe they will not take such a course of action. They have given no indication to Boeing that they will disallow Li-Ion batteries on aircraft and in fact are working with Cessna to certify them for the Citation family of business jets.

I am not completely convinced about the points raised above. First, as long as the root cause is not know, then the solution is not known either. And I am convinced it will not be a trivial "bad battery" cause. So how do you know that switching to an other type of battery takes longer than fixing the problem you have today? By the time Cessna is done with fixing their Li-Ion battery system, it will have taken them 18 months and today the Citation Jets are flying with NiCads as a temporary solution.


User currently offlinekanban From United States of America, joined Jan 2008, 3575 posts, RR: 27
Reply 103, posted (1 year 6 months 4 weeks 4 hours ago) and read 13939 times:
Support Airliners.net - become a First Class Member!

Quoting sonomaflyer (Reply 92):
Airbus was smart to simply say, "peace out!" They avoided the whole issue by switching battery technologies at little cost to their design. It's not nearly that simple with the 787 given the power requirements and the fact the a/c is flying and in full production.

I've been trying to place an article I saw that implied Airbus will use Li-Ion on the first three test A/c and the change will be in unit #4. If true , it's not as simple swap as some envision.


User currently offlineAesma From France, joined Nov 2009, 6688 posts, RR: 12
Reply 104, posted (1 year 6 months 4 weeks 3 hours ago) and read 13826 times:

Quoting Stitch (Reply 91):
Solely because they were in a position to do so.

If they were producing customer frames right now (which I believe they should have been per the original production plan), they'd be sweating bullets as much as Boeing would be.

I'm not arguing that. What I'm saying is that a Li-Ion battery has benefits, it's just not the holy grail that you must absolutely have. If Airbus was so quick in changing their mind, we can even wonder if they weren't already having doubts before the 787 troubles.

Quoting sonomaflyer (Reply 92):
Recall the 787 has electric brakes, bleedless engines, a different and more powerful APU design, electric brakes etc. The power requirements for the 787 battery appear bigger than the 350.

As I showed in a previous thread, the A350 APU is more powerful than the 787 APU. The only thing the 787 batteries have to do that the A350 don't is powering the brakes in case the aircraft runs out of fuel/fuel contamination. From what I got in the other threads it's also possible the 787 is more taxing than typical aircraft on batteries for tasks like refueling, but I don't know where the A350 will stand on such matters (apparently Boeing didn't really know for the 787 either, considering how many batteries ended up drained).



New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 105, posted (1 year 6 months 4 weeks 3 hours ago) and read 13896 times:

Looks like ZA005 could be back in the air soon. Sign off on the certification plan indicates that the FAA is not only happy with the concept but has blessed the certification procedures so testing (ground/flight) could begin immediately -- if rumors prove to be true.

http://www.reuters.com/article/2013/...mp;feedName=marketsNews&rpc=43


User currently onlineADent From United States of America, joined Dec 2006, 1387 posts, RR: 2
Reply 106, posted (1 year 6 months 4 weeks 3 hours ago) and read 13846 times:

Quoting sankaps (Reply 108):
My question is even if the FAA approves Boeing's proposed solution, is there a possibility that some airlines (especially the Japanese carriers) and pilot / crew unions may refuse to fly until the root cause is found and fixed? What are the odds of that happening?

I guessed in an earlier version that the Chinese (and maybe Russians) would cause the most problems. There were 787s ready for delivery waiting for Chinese approval before the grounding. And don't forget delayed India approval.


User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 107, posted (1 year 6 months 4 weeks 3 hours ago) and read 13855 times:
Support Airliners.net - become a First Class Member!

Quoting AngMoh (Reply 111):
I am not completely convinced about the points raised above. First, as long as the root cause is not know, then the solution is not known either.

I would expect this is why Boeing is offering stronger containment. We're all assuming that there is a root cause for this issue, but that may not be the case. So the FAA cannot realistically park the 787 indefinitely until a root cause is found. It is not possible to design a failure-impossible system, which is why we "settle" for fail-safe systems. There is skepticism if the current system is fail-safe, so improvements are being demanded.

If and when a root cause is found, that can then be addressed separately and, in conjunction with the improved containment, makes the system that much more fail-safe.



Quoting AngMoh (Reply 111):
So how do you know that switching to an other type of battery takes longer than fixing the problem you have today?

Because the 787's DC electrical systems were designed around the properties of this battery. So a new battery is going to have to be tested and certified to ensure it works properly and if it does not, changes will need to be made and then more testing will need to be done prior to final certification.



Quoting Aesma (Reply 113):
If Airbus was so quick in changing their mind, we can even wonder if they weren't already having doubts before the 787 troubles.

If Airbus had concerns about the safety/suitability of Li-Ion batteries, I expect they would not have moved forward with them. They could have used NiCad from Day 1, after all. And let us not forget that the flight test airframes will start testing with the current Li-Ion battery and the switch will be made to NiCad prior to the certification process for the battery subsystem. If Airbus was truly concerned, they could have pushed back the start of flight test and accepted an additional delay to EIS.


User currently offlinePHX787 From Japan, joined Mar 2012, 7639 posts, RR: 18
Reply 108, posted (1 year 6 months 4 weeks 2 hours ago) and read 13758 times:

For practicality's sake, and for the fact that I can never get a word in here with you guys especially when it comes to news regarding 787 operators, I've began this thread (where you can also discuss other forms of Japanese aviation)
Japanese Aviation News Thread 2013 (by PHX787 Mar 6 2013 in Civil Aviation)

I can never keep track of this thread anymore, for the sake of news, here you all go   



我思うゆえに我あり。(Jap. 'I think, therefore I am.')
User currently offlineAngMoh From Singapore, joined Nov 2011, 488 posts, RR: 0
Reply 109, posted (1 year 6 months 4 weeks 2 hours ago) and read 13707 times:

Quoting Stitch (Reply 116):
Because the 787's DC electrical systems were designed around the properties of this battery. So a new battery is going to have to be tested and certified to ensure it works properly and if it does not, changes will need to be made and then more testing will need to be done prior to final certification.

I think the real question is what is different in the 787 - and we can just guess because the details are proprietary to Boeing. I have my personal theory based on symptoms and if I am in the right direction, change to a NiCad is not possible.

If the battery is used as a traditional startup/backup battery, change to another type is definitely possible and if that takes less time than fixing the problem depends on what the cause and fix is.

But if the system is designed that the performance if a Li-Ion battery is critical to the performance of the system as a whole, then I fear that the fix and verification of the fix is not straightforward at all because I don't the the root cause is in the battery itself.


User currently offlinePanAmPaul From United States of America, joined Jan 2013, 242 posts, RR: 0
Reply 110, posted (1 year 6 months 4 weeks 2 hours ago) and read 13700 times:

Interesting interview in the WSJ

LaHood Still Has Questions On 787s
-http://online.wsj.com/article/SB10001424127887324034804578344831354683720.html


User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 111, posted (1 year 6 months 4 weeks 2 hours ago) and read 13668 times:

Quoting PanAmPaul (Reply 119):
LaHood Still Has Questions On 787s

Quote:
Mr. LaHood, a former Republican congressman with a history of frosty relations with some FAA leaders, has been lukewarm from the beginning about locking in changes before investigators pinpoint a specific cause of the 787's battery problems. When the 787 was grounded, he publicly pledged it wouldn't take off again with passengers until investigators determined the precise cause of the overheating batteries and regulators felt "1,000% sure" of the plane's safety.

This may present a problem. If the NTSB doesn't come up with a root cause in their update tomorrow, and all Boeing proposed was a containment fix on Feb 22nd, I don't see how the FAA will give the green light to a retrofit to get the 787 back in the air anytime soon.



International Homo of Mystery
User currently offlineBoeingVista From Australia, joined Jan 2009, 1581 posts, RR: 3
Reply 112, posted (1 year 6 months 4 weeks 2 hours ago) and read 13646 times:

Boeing 787 Circuits Burned on ANA Planes Last Year, Union Says

Quote:
Tsue said he doesn’t know whether there is a link between circuit-board damage and the battery fires and that he has sent a letter to the nation’s transport minister asking that “issues” uncovered in the 787 be reconsidered. Boeing’s Dreamliners have yet to fly commercially after the January grounding, the first time in 34 years an entire airplane model has been pulled from service.

“The circuit board case on April 7 was serious and caused damage to the surrounding area,” Tsue said.
http://www.bloomberg.com/news/2013-0...a-planes-last-year-union-says.html

Something else for the JTSB to consider.

[Edited 2013-03-06 18:55:03]


BV
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 113, posted (1 year 6 months 4 weeks 1 hour ago) and read 13600 times:

Quoting AeroWesty (Reply 120):
This may present a problem. If the NTSB doesn't come up with a root cause in their update tomorrow, and all Boeing proposed was a containment fix on Feb 22nd, I don't see how the FAA will give the green light to a retrofit to get the 787 back in the air anytime soon

The odds of the NTSB coming up with a root cause at tomorrows briefing is about "10 to the minus 7". The "precise cause of the overheating batteries" may never be determined. Mr. LaHood is a career politician who is about to leave office and with a BS Education/Sociology he's probably the least qualified person to determine whether the 787 should remain grounded. Hopefully he will listen to the qualifed people who work for him and not stand by an emotional statement you'd expect from a politician.


User currently offline2175301 From United States of America, joined May 2007, 1072 posts, RR: 0
Reply 114, posted (1 year 6 months 4 weeks 1 hour ago) and read 13603 times:

Quoting AeroWesty (Reply 105):
Hopefully there'll be some pearls of wisdom tomorrow which the FAA may use in determining whether to approve the fix Boeing presented last week.

I assure you that both Boeing and the FAA knows exactly what the NTSB report will say; and I am sure that they had an opportunity to comment on the draft report.

Nothing the NTSB has done, questioned, or preliminary concluded, has been done in a vacuum without Boeing and the FAA being in the know.

The very reason why the proposed Boeing Fix will in fact be approved is because the key findings of the NTSB have been known by both Boeing and the FAA for several weeks and Boeing and the FAA have in fact been talking discreetly.

Have a great day,


User currently offlineYVRLTN From Canada, joined Oct 2006, 2477 posts, RR: 0
Reply 115, posted (1 year 6 months 4 weeks 1 hour ago) and read 13529 times:

Quoting Wisdom (Reply 100):
it's clear to me that there is a fundamental issue with the electrical system

I never got a reply to post 8 - I am not stirring the pot, it is a genuine question - I believe the problem could be as simple as this and I know top Boeing electricians have conclude the same, but have been rebuffed.

Quoting YVRLTN (Reply 8):
Quoting mjoelnir (Reply 4):
Static electricity has been the bane of electrical installations. That is why you ground (or earth) everything in sight and bad grounding has been the reason for many strange electrical happenings.

So if there were faulty connectors, or if they were not installed correctly, even if it didnt result in arcing exactly it wouldnt be earthed, so could that result in the battery issues we have seen because it is the "weakest link" in the system?



Follow me on twitter for YVR movements @vernonYVR
User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 116, posted (1 year 6 months 4 weeks 1 hour ago) and read 13483 times:

Quoting 2175301 (Reply 123):
The very reason why the proposed Boeing Fix will in fact be approved is because the key findings of the NTSB have been known by both Boeing and the FAA for several weeks and Boeing and the FAA have in fact been talking discreetly.

You're basically saying that "the fix is in", which may very well be the case. But since there has been no indication that a root cause has been determined it is difficult to believe that these regulatory groups would risk the political fallout by being perceived to be in bed with Boeing.


User currently offline2175301 From United States of America, joined May 2007, 1072 posts, RR: 0
Reply 117, posted (1 year 6 months 4 weeks ago) and read 13360 times:

Quoting ServantLeader (Reply 125):
You're basically saying that "the fix is in", which may very well be the case. But since there has been no indication that a root cause has been determined it is difficult to believe that these regulatory groups would risk the political fallout by being perceived to be in bed with Boeing.

You are looking at it wrong. This is not a case of "the fix is in" - its a case where Boeing will have ensured what the FAA is looking for for a fix based on the identified issues - and then Boeing will propose that as the fix.

I work in the Nuclear Industry - and we do this all the time with the NRC when there is a problem. We flat out ask what the NRC is looking for as a solution (when it is not obvious); and then we proceed from there.

A lot of people have claimed that there is a problem with the NRC (and the FAA) because they have never actually denied a major project. What those people have not seen is the many (and often hundreds of changes) that were done to a major project along the way to meet the NRC (and I am sure the FAA) requirements before the final licensing determination. I am not aware of any major nuclear project, nor any airline, that the original design (and all the details) were approved. In fact, it was denied. But it was denied piece by piece in a multi-year review process where the company could then come back with a new design for that area that would be approved. The final overall review is nothing more than an approval of all of the design changes along the way that ensured that the project (airplane) actually meets regulatory requirements.

In this case - keep in mind that the original approval for the plane allowed batteries to fail (in thermal run-away). I am sure that will not change as other batter technologies also have thermal runaway failures. There is an open issue with how well the containment worked. There may be an issue with how often the batteries failed (but, 2 failures in a relatively short time may be a statistical outlier; and there could be a good debate over what is an acceptable failure rate).

We know that Boeing is improving the containment (and it is likely that the FAA essentially told Boeing that "we are not sure how we can approve return to service with the existing containment" - which is regulator lingo for "improve the containment"; and likely used similar "hint" sentences to indicate what minimal level of a new containment that would be approved along the line of "we see no reason that we would not approve a containment that....). That is how the game is played - and that is why I do not see any real problem for Boeing to have their solution approved as long as the testing validates that it meets its design intent.

Have a great day,


User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3413 posts, RR: 4
Reply 118, posted (1 year 6 months 3 weeks 6 days 23 hours ago) and read 13310 times:

Quoting 2175301 (Reply 126):
In this case - keep in mind that the original approval for the plane allowed batteries to fail (in thermal run-away)

I'm not sure there is any battery technology that doesn't see a self sustaining rise in temp when it suffers from an internal short or other damage. Certainly the millions of lead-acid batteries in cars do.... while also releasing hydrogen and liquid acid once the plastic container fails.


User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2241 posts, RR: 5
Reply 119, posted (1 year 6 months 3 weeks 6 days 23 hours ago) and read 13280 times:

Quoting Sassiciai (Reply 65):
Much better, more relevant, and more interesting!

Sorry, interests are not overlapping.

Quoting nomadd22 (Reply 95):
I just disposed of a smoking nicad battery. Nicads can and do run away just like lithiums. They just don't get the same press.

They would (get the same press) if they would (be as critical and especially also have frequent thermal runaways in flight). But as the later does not happen, the former does also not happen and your comparison falls flat.

Quoting Stitch (Reply 98):
The FAA knew that even with the Special Conditions, the batteries could catch fire and/or leak electrolyte, which is why they required some form of containment for the cells in 2007 when they published the Special Conditions.

No, the key requirement did not allow the battery or any cell to run away thermally.

Quoting BEG2IAH (Reply 99):
The first production aircraft is not B787, but Grumman's Global Hawk using Goodrich electric brakes. Bombardier also tested Meggitt's EBrake in October 2008. New Eurocopter X4 will have electric brakes.

Good, the 787 has the same brakes like a drone and a future helicopter. Should that convince those who doubt? Helicopters have usually been fine with brakes like that:

View Large View Medium
Click here for bigger photo!

Photo © S. Mendes - Aerospray

Quoting kanban (Reply 112):
If true, it's not as simple swap as some envision.

It is true and it is not simple to swap.

Quoting Stitch (Reply 116):
We're all assuming that there is a root cause for this issue, but that may not be the case.

There is always a root cause.

Quoting Stitch (Reply 116):
Because the 787's DC electrical systems were designed around the properties of this battery.

It is not impossible to recreate the same behaviour with other kind of batteries. Even you suggest a chemistry change, which changes a lot of the batteries properties. Just not the weight.

Quoting BoeingVista (Reply 121):
Boeing 787 Circuits Burned on ANA Planes Last Year, Union Says

Quote:
Tsue said he doesn’t know whether there is a link between circuit-board damage and the battery fires and that he has sent a letter to the nation’s transport minister asking that “issues” uncovered in the 787 be reconsidered. Boeing’s Dreamliners have yet to fly commercially after the January grounding, the first time in 34 years an entire airplane model has been pulled from service.

“The circuit board case on April 7 was serious and caused damage to the surrounding area,” Tsue said.

So onboard and in the systems of 787 aircraft have been how many fires? At least 4? All related to the electrical system? I must say that I am concerned about a potential underlying issue with the design that could have driven these events. The situation is really serious.

I think all of us should really have only one interest: that not any compromise is allowed only that the 787 flies soon again. Because if the same issue or a similar one raises its ugly head the next time, we might be facing a debris field one day somewhere. In that case the damage to Boeings reputation, the negative emotions and in the end even the impact in the ability to do business will far outweight the cost of anything proposed so far to fix the "battery issue".

Look, the 787 familiy is too young to have that kind of press. Any issue in the design must be eliminated in order to live on for decades.


User currently offlinePart147 From Ireland, joined Dec 2008, 503 posts, RR: 0
Reply 120, posted (1 year 6 months 3 weeks 6 days 21 hours ago) and read 12971 times:

Quoting Stitch (Reply 116):
I would expect this is why Boeing is offering stronger containment. We're all assuming that there is a root cause for this issue, but that may not be the case. So the FAA cannot realistically park the 787 indefinitely until a root cause is found. It is not possible to design a failure-impossible system, which is why we "settle" for fail-safe systems. There is skepticism if the current system is fail-safe, so improvements are being demanded.

If and when a root cause is found, that can then be addressed separately and, in conjunction with the improved containment, makes the system that much more fail-safe.

Stitch I respect your opinions, but just I have to comment on two of your statements above...

"We're all assuming that there is a root cause for this issue, but that may not be the case." - there may be more than one root cause. And if that's the case - the FAA WOULD indeed be negligent if they let the 787 fly again without all root causes being properly identified and solved/fixed.

In My Opinion - I think that Boeing is onto a WIN-WIN situation if they do push the FAA into signing off on the proposed fix - that way they get back flying (WIN 1) - but if this fix itself is not enough and (God forbid!) another 787 problem arose in service - then Boeing can always say - "well the FAA checked out our fix and said it was okay for service" and push the blame over to the FAA (WIN 2)

"...makes the system that much more fail-safe." - from my perspective - FAIL SAFE is an absolute term - it either is or isn't - otherwise we stray into trying to define terms like 'fail-safe' and 'fail safer'

Part147



It's better to ask a stupid question during training, rather than make a REALLY stupid mistake later on!
User currently offlineseahawk From Germany, joined May 2005, 1069 posts, RR: 0
Reply 121, posted (1 year 6 months 3 weeks 6 days 20 hours ago) and read 12842 times:

The improved containment (I would call it a real containment now) is surely a fix to get the planes flying again, but I am not sure all national safety agencies will accept it, at least not without some limitations imposed on 787 ops. The fix just reduces the effects of a battery failure and should avoid / contain a thermal event within the battery pack, but it surely is unable to prevent a battery failure.
The doubts about the MTBF of the batteries is not reduced by the fix. I would also like to know what the standing operating procedure is, when the 787 has a battery fail in flight, even without any additional effects (like smoke in the cabin). Is it still a failure bad enough to warrant or require a safety landing?
As the FAA (or any similar agency) I would consider putting limitations on the ETOPS rating of the 787 until the root cause is found and fixed, so that i can say I did something in case of more battery failures.

Then there is the report about the circuit board fires on 787s.If the report from the workers union is correct and ANA alone had 3 failures in 2012 (one with fire and damage to th surrondings), the chances for a lifting of the grounding is small imho.

I wonder if the FAA will have the balls to lift the grounding alone, even if the Japanese, European or Chinese safety boards to do agree with this move. I would be surprised if the FAA does this. (if the Japanese and Europeans do not go along)


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 122, posted (1 year 6 months 3 weeks 6 days 13 hours ago) and read 12096 times:

The way Boeing stock is up this morning, somebody thinks it will be a good news day.

User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 123, posted (1 year 6 months 3 weeks 6 days 13 hours ago) and read 12072 times:
Support Airliners.net - become a First Class Member!

Quoting rheinwaldner (Reply 122):
No, the key requirement did not allow the battery or any cell to run away thermally.

And if the FAA truly believed that a cell would never enter thermal runway, they would have been content to allow the use of a plastic container for the battery pack because it is lighter than a metal one. That they demanded Boeing use a containment system that they believed would contain a thermal runway event is proof enough to me that they knew the Law of Probabilities ensured a thermal runway event would happen (even if the chances were one in a million or whatever the standard is) and they wanted to take measures to prevent it from bringing down the airframe.



Quoting rheinwaldner (Reply 122):
It is not impossible to recreate the same behaviour with other kind of batteries. Even you suggest a chemistry change, which changes a lot of the batteries properties. Just not the weight.

I have never argued a chemistry change was impossible (in fact, I've been arguing for it since Day One). I just get the feeling from some posters that they believe all Boeing has to do is replace the Li-Ion battery with a NiCad of the same capacity and the issue will be "fixed" and the 787 can immediately return to service. The truth of the matter is that any such change will require a new set of testing and certification to verify operability and compliance and that could take an extended period of time. I would expect a cathode chemistry change with the existing Li-Ion battery would also require new testing and certification, but that would be significantly less than changing to NiCad, NiMH or Lead Acid.



Quoting Part147 (Reply 123):
In My Opinion - I think that Boeing is onto a WIN-WIN situation if they do push the FAA into signing off on the proposed fix - that way they get back flying (WIN 1) - but if this fix itself is not enough and (God forbid!) another 787 problem arose in service - then Boeing can always say - "well the FAA checked out our fix and said it was okay for service" and push the blame over to the FAA (WIN 2

I highly doubt that argument would hold up in the civil lawsuits that would result in the loss of a 787 airframe with injury and or death of passengers aboard. I am sure Boeing feels the same and while they want to get the plane back in the air as quickly as possible, they understand that doing so in a slip-shod manner will only bite them in the ass.



Quoting Part147 (Reply 123):
"...makes the system that much more fail-safe." - from my perspective - FAIL SAFE is an absolute term - it either is or isn't - otherwise we stray into trying to define terms like 'fail-safe' and 'fail safer'

Well to be honest, the current PoS containment system has proven itself "fail safe" because JA804A made a safe and controlled landing. And I have seen nothing that says if JA829J had been in the air it would not have been able to make a safe landing within 180 minutes of a diversion point (the current limit per the JCAB for Japanese carriers).



Quoting seahawk (Reply 124):
I would also like to know what the standing operating procedure is, when the 787 has a battery fail in flight, even without any additional effects (like smoke in the cabin). Is it still a failure bad enough to warrant or require a safety landing?

It appears that if you lose the APU battery, you cannot be more than 180 minutes from a diversion point per the MEL. If anyone has a current 787 FCOM, they might have a better answer.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 124, posted (1 year 6 months 3 weeks 6 days 12 hours ago) and read 12145 times:

Quoting Stitch (Reply 126):
It appears that if you lose the APU battery, you cannot be more than 180 minutes from a diversion point per the MEL. If anyone has a current 787 FCOM, they might have a better answer.

If you takeoff with a dead/missing APU battery you are limited to 180 ETOPS (MEL/DDPG not FCOM). Question is if you are on an ETOPS flight and lose the APU battery what are your procedures--right now I don't think there are any messages the crew would get in flight (without going places they don't normally go) indicating an APU battery failure but i'm guessing that may change.

There may be a STATUS message.

[Edited 2013-03-07 08:42:54]

User currently offlineAeroWesty From United States of America, joined Oct 2004, 20671 posts, RR: 62
Reply 125, posted (1 year 6 months 3 weeks 6 days 12 hours ago) and read 12146 times:

Quoting 7BOEING7 (Reply 125):
The way Boeing stock is up this morning, somebody thinks it will be a good news day.

Holy moly, $81.50? That's astounding.



International Homo of Mystery
User currently offlineKarelXWB From Netherlands, joined Jul 2012, 11819 posts, RR: 33
Reply 126, posted (1 year 6 months 3 weeks 6 days 12 hours ago) and read 12082 times:

And here is the NTSB interim report:

http://t.co/BeUMF079Hl

547 pages



Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offline2175301 From United States of America, joined May 2007, 1072 posts, RR: 0
Reply 127, posted (1 year 6 months 3 weeks 6 days 11 hours ago) and read 11919 times:

Quoting rheinwaldner (Reply 122):
There is always a root cause.

No, there is usually a Root Cause (or perhaps 2); but there are cases where there is no root cause.

A root cause is an item where by changing that single item it will permanently and definitively prevent the event from occurring. It is actually not that uncommon to not find an actual root cause (perhaps 10-15% of root cause investigations do not find a root cause). Note that I am a Trained and Certified Root Cause Investigator (to the equivalent level of what the NTSB Root cause leads are; and have run Root Cause investigations).

The other item is that not all root causes are solvable (or solvable in any reasonable economic form); and there are a number of root causes that are identified and just allowed to exist. Often routine replacement of parts is done to minimize such root causes (which prevents most of the failures); but there are cases where that is not practical either.

Given that it has been known for decades that most common batteries can enter thermal run away (and this thread has routinely cited lead/acid, NiCads, and of course Li-Ion) I am sure that if the battery industry knew of the root cause to prevent these events in an economic fashion that they would have addressed them.

Quoting Part147 (Reply 123):
"We're all assuming that there is a root cause for this issue, but that may not be the case." - there may be more than one root cause. And if that's the case - the FAA WOULD indeed be negligent if they let the 787 fly again without all root causes being properly identified and solved/fixed.


The FAA (and all other international certification agencies) routinely allow planes to fly without "fixing" the root causes of various issues. Their is an economic balance vs the risk of significant event in determining if a root cause of a problem has to be addressed (which is the key function of the FAA and other international certification agencies). Otherwise there would not be a single aircraft certified to fly anywhere in the world. Nor would there be any automobiles on the road, etc.

Have a great day,


User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 128, posted (1 year 6 months 3 weeks 6 days 11 hours ago) and read 11971 times:
Support Airliners.net - become a First Class Member!

Quoting KarelXWB (Reply 129):
And here is the NTSB interim report...547 pages.

For those interested in the Cliff Notes version: the NTSB has still not identified a root cause.

They also announced both a forum and an investigative hearing in mid-April. The forum will explore Li-Ion technology and how it applies to transportation safety (so this could include consumer Li-Ion batteries). The hearing will be to focus on the certification and design of the 787 battery system.

The FAA may still move to approve Boeing's proposed fix before the hearing, however considering that the FAA have stated that any fix would require rigorous testing, it will likely not be in place before the hearing.


User currently offlineBEG2IAH From United States of America, joined Apr 2004, 972 posts, RR: 18
Reply 129, posted (1 year 6 months 3 weeks 6 days 11 hours ago) and read 11807 times:
Support Airliners.net - become a First Class Member!

Quoting rheinwaldner (Reply 122):
Good, the 787 has the same brakes like a drone and a future helicopter. Should that convince those who doubt? Helicopters have usually been fine with brakes like that:

Again, at least three different sets of electric brakes have been certified for commercial fixed-wing aircraft including Safran (Messier-Bugatti-Dowty), Goodrich, and Meggitt. You are free to choose to ignore that fact. Also, helicopters have wheels too (more often than skids) and your sarcasm is out of place like on many other points you raise.



FAA killed the purpose of my old signature: Use of approved electronic devices is now permitted.
User currently offlineblrsea From India, joined May 2005, 1423 posts, RR: 3
Reply 130, posted (1 year 6 months 3 weeks 6 days 11 hours ago) and read 11671 times:

A brief summary has been posted in the news.com article below. Basically, they haven't identified a root cause yet. The following is the executive summary of the report from that link ...

NTSB: Boeing Dreamliner blaze probe needs more time

Quote:
Here's the full executive summary:

The National Transportation Safety Board (NTSB) notes that the information discussed in this interim factual report is based on initial findings from the investigation of this incident. Because the investigation is continuing, no conclusions or recommendations are being made at this time. Readers are encouraged to access the public docket for this incident (DCA13IA037) for further details about the information presented in this report. In addition, readers are advised that the information presented in this report could change if new evidence becomes available.

On January 7, 2013, about 1021 eastern standard time, smoke was discovered by cleaning personnel in the aft cabin of a Japan Airlines (JAL) Boeing 787-8, JA829J, which was parked at a gate at General Edward Lawrence Logan International Airport (BOS), Boston, Massachusetts. About the same time, a maintenance manager in the cockpit observed that the auxiliary power unit (APU)--the sole source of airplane power at the time--had automatically shut down. Shortly afterward, a mechanic opened the aft electronic equipment (E/E) bay and found heavy smoke and fire coming from the front of the APU battery case. No passengers or crewmembers were aboard the airplane at the time, and none of the maintenance or cleaning personnel aboard the airplane was injured. Aircraft rescue and firefighting personnel responded, and one firefighter received minor injuries. The airplane had arrived from Narita International Airport, Narita, Japan, as a regularly scheduled passenger flight operated as JAL flight 008 and conducted under the provisions of 14 Code of Federal Regulations Part 129.

The APU battery provides power to start an APU during ground and flight operations. Flight data recorder (FDR) data showed that the APU was started about 1004 while the airplane was being taxied to the gate after arrival at BOS. The FDR data also showed that, about 36 seconds before the APU shut down at 1021:37, the voltage of the APU battery began fluctuating, dropping from a full charge of 32 volts to 28 volts about 7 seconds before the shutdown.

The APU battery consists of eight lithium-ion cells that are connected in series and assembled in two rows of four cells. Each battery cell has a nominal voltage of 3.7 volts. The cells have a lithium cobalt oxide compound chemistry and contain a flammable electrolyte liquid.

External observations of the battery involved in this incident showed, among other things, that the right side of the battery case appeared to have the most extensive damage of the four battery sides. Disassembly of the battery revealed that the cells that were located in the left side of the battery (cells 1 through 4) generally exhibited the least thermal and mechanical damage and that the cells that were located in the right side of the battery (cells 5 through 8) generally exhibited the most thermal and mechanical damage. Thermal damage was the most severe near cell 6. Continuity measurements using a digital volt meter indicated that all of the cells were found to be electrically short circuited except for cell 8.

The APU battery was configured so that each cell's vent disc, which is a plate that ruptures when the internal pressure in a cell reaches a predetermined level, would be oriented toward the exterior of the battery. Disassembly of the battery showed that the vent discs on cells 1 through 3 were opened slightly, the cell 4 vent disc was intact (although weight measurements indicated that the cell lost some electrolyte), and the vent discs on cells 5 through 8 had opened more completely, leaving a ruptured appearance.

The NTSB is examining the certification and testing of the 787 battery system as part of its investigation of this incident. According to the Federal Aviation Administration (FAA), the 787 incorporated "novel or unusual design features," including the use of lithium-ion batteries. Because the FAA determined that applicable airworthiness requirements did not address lithium-ion batteries, the agency issued nine special conditions regarding the use of these batteries on the 787. These nine special conditions were intended to ensure that this new technology would not pose a greater safety risk than other technologies addressed in existing airworthiness regulations.

During the 787 certification process, Boeing performed a safety assessment (known as functional hazard assessment) to determine the potential hazards that various failure conditions of electrical system components could introduce to the airplane and its occupants. Boeing also determined that the probability that a battery could vent was once in every 10 million flight hours. As of January 16, 2013, the in-service 787 fleet had accumulated less than 52,000 flight hours, and during this period two events involving smoke emission from a 787 battery (the BOS event and a second event in Japan being investigated by the Japan Transport Safety Board) had occurred on two different 787 airplanes.

The NTSB's investigation into the probable cause of the 787 battery fire at BOS is continuing. The NTSB is also continuing to review the design, certification, and manufacturing processes for the 787 lithium-ion battery system.


User currently offlinetugger From United States of America, joined Apr 2006, 5627 posts, RR: 8
Reply 131, posted (1 year 6 months 3 weeks 6 days 10 hours ago) and read 11594 times:

Quoting 2175301 (Reply 130):
Have a great day,

Thank you for the direct and informative post. Always good to hear from someone who's job and training is in what is being debated.

Tugg



I don’t know that I am unafraid to be myself, but it is hard to be somebody else. -W. Shatner
User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 132, posted (1 year 6 months 3 weeks 6 days 9 hours ago) and read 11286 times:

Interesting item from the report --

"When smoke is detected, the avionics cooling function is designed to exhaust smoke overboard through fans in the cooling ducts and changing supply valve positions (and the use of differential pressure if the airplane is in flight). During this incident, the supply valves (which are electrically driven) lost electrical power after the APU shut down because the APU was the only source of electrical power being used at the time. As a result, smoke generated by the APU battery could not be effectively redirected outside the cabin and aft E/E bay."

So the smoke from the failed APU battery could not be vented overboard because -- the APU battery had failed.


User currently offlinePITingres From United States of America, joined Dec 2007, 1145 posts, RR: 13
Reply 133, posted (1 year 6 months 3 weeks 6 days 9 hours ago) and read 11164 times:

Quoting hivue (Reply 135):
So the smoke from the failed APU battery could not be vented overboard because -- the APU battery had failed.

True enough, as far as it goes; in flight, other power sources would have been available. I don't know if the on-ground situation was an oversight, or if the intent was that on the ground, one simply opens the door and waits for the smoke to clear.

Since it appears that a dedicated vent will be part of the proposed solution, this is kind of a moot point though.



Fly, you fools! Fly!
User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 134, posted (1 year 6 months 3 weeks 6 days 9 hours ago) and read 11154 times:
Support Airliners.net - become a First Class Member!

Quoting hivue (Reply 135):
So the smoke from the failed APU battery could not be vented overboard because -- the APU battery had failed.

And it was the only source of electrical power at the time.

In flight, the valve should have multiple alternate power sources to open it (the four engine generators, the two APU generators if the APU was still active, and the RAT).

And if the plane had been connected to ground power, I would think that would have provided power to open the valve, as well.


User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2241 posts, RR: 5
Reply 135, posted (1 year 6 months 3 weeks 6 days 7 hours ago) and read 10805 times:

Quoting 2175301 (Reply 130):
Quoting rheinwaldner (Reply 122):
There is always a root cause.

No, there is usually a Root Cause (or perhaps 2); but there are cases where there is no root cause.

A root cause is an item where by changing that single item it will permanently and definitively prevent the event from occurring. It is actually not that uncommon to not find an actual root cause (perhaps 10-15% of root cause investigations do not find a root cause).

There might be not a single root cause, but there is always one or more root causes. Not finding it is something completely different than saying there is none. Note I am trained in root cause analysis too.

There is one or more root reasons why the batteries have burned. Denying that won't help anybody. We might face a situation where they will not be found, but again, that would make it impossible to meet the FAA's own requirements in the future. We would hear of new battery fires with a high probability. That would not be an easy situation to arrange with. For the FAA, for Boeing as for us.

Quoting 2175301 (Reply 130):
Their is an economic balance vs the risk of significant event in determining if a root cause of a problem has to be addressed (which is the key function of the FAA and other international certification agencies).

Of course. I am very familiar with trade offs between risk and cost. I did not speak about that before.

Quoting Stitch (Reply 126):
And if the FAA truly believed that a cell would never enter thermal runway, they would have been content to allow the use of a plastic container for the battery pack because it is lighter than a metal one.

They don't need to believe that it would be possible to meet a requirement to put it in place. That should be clear. I agree that it is virtually impossible to meet that requirement. But the FAA has mandated it and they certified a solution that broke it. The mess is there.

Quoting Stitch (Reply 126):
in fact, I've been arguing for it since Day One

Thats what I meant. I just wanted to highlight the fact that the chemistry change would also impact the electrical systems that were built around it, because the properties of the battery would also be altered with a chemistry change (e.g. effect of temperature, high-C charging and discharging capabilities).

Quoting Stitch (Reply 126):
I just get the feeling from some posters that they believe all Boeing has to do is replace the Li-Ion battery with a NiCad of the same capacity and the issue will be "fixed" and the 787 can immediately return to service.

Of course this is nonsense. Going the NiCad path would have a tremendous impact on the design and on the grounding times. Going to NiCad would probably have the most serious impact on the grounding of any thinkable measures. There is no way to "just" switch to NiCad. A lot of brain effort can be spend for other solutions until that path will become the easiest.

Quoting Stitch (Reply 126):
I would expect a cathode chemistry change with the existing Li-Ion battery would also require new testing and certification

Correct. That's the problem. But let's not forget that retesting basically applies to any solution.

Quoting BEG2IAH (Reply 132):
Again, at least three different sets of electric brakes have been certified for commercial fixed-wing aircraft including Safran (Messier-Bugatti-Dowty), Goodrich, and Meggitt.

I don't doubt that the brakes are sound. The issue are the batteries. And the electrical brakes might be one of the root cause that tough-to-meet requirements have been put on the batteries. Root cause analysis continues to ask "why?" until there is no more reasonable answer.

So the selection of electrical brakes, that require the battery to have unusual endurance and current capacity, that might make some risky battery chemistry more desireable, could indeed be one root cause of this whole story.


User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 136, posted (1 year 6 months 3 weeks 6 days 7 hours ago) and read 10738 times:

Quoting Stitch (Reply 137):
the two APU generators if the APU was still active

It wouldn't be with a failed APU battery.

Quoting Stitch (Reply 137):
and the RAT

I wonder if the RAT can power the E/E bay vent system? Also, if the fans aren't working in flight I wonder if differential pressure is enough to vent the bay adequately?


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 137, posted (1 year 6 months 3 weeks 6 days 6 hours ago) and read 10558 times:

Quoting hivue (Reply 139):
I wonder if the RAT can power the E/E bay vent system? Also, if the fans aren't working in flight I wonder if differential pressure is enough to vent the bay adequately?

I don't think so. If you stand in front of those vents, they blow your hair away quite hard. So the RAT would not be sufficient if you consider everything else that would have to be powered.
Differential pressure will work if you can maintain pressurisation. But if you're down to a RAT to power elctrics, regardless of engines providing thrust, on the B787 the pressurisation is also going to fall away... no bleed ducts.


What is all this discussion about the electric brakes?
It's just some hydraulic systems being replaced by wires and electricity, the basic architecture is the same.
You make it sound like the wheels are arced to a stop...

State of the art, marketing here, marketing there, marketing everywhere, until the heat damages the electric components and the customer (airlines) pays the bills.
One thing I know for certain is that whenever a brake assy is in for repairs, it's usually for a temp sensor, or its connector. I've hardly ever heard of brakes leaking hydraulics and even then, you just put a new pipe on it and everything is fixed. Hydraulics are very tough and they don't mind heat, but electric systems do mind heat.


User currently offlinesonomaflyer From United States of America, joined Apr 2010, 1817 posts, RR: 0
Reply 138, posted (1 year 6 months 3 weeks 6 days 6 hours ago) and read 10506 times:
Support Airliners.net - become a First Class Member!

Quoting Wisdom (Reply 140):
What is all this discussion about the electric brakes?
It's just some hydraulic systems being replaced by wires and electricity, the basic architecture is the same.
You make it sound like the wheels are arced to a stop...

I think the discussion centers around power demand on the battery to stop the a/c in the event of a failure of both engines and the APU (itself a very remote possibility).

New new information coming from Japan about the panels should be "old news" to Boeing and hopefully they have a team examining the panels for issues relating to FoD prevention (again) or material defects. They'd better hope that the NH and UA panel issues aren't related to a design fault.


User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 139, posted (1 year 6 months 3 weeks 6 days 6 hours ago) and read 10477 times:
Support Airliners.net - become a First Class Member!

Quoting sonomaflyer (Reply 141):
They'd better hope that the NH and UA panel issues aren't related to a design fault.

Boeing already isolated it to a bad production batch.


User currently offlinesonomaflyer From United States of America, joined Apr 2010, 1817 posts, RR: 0
Reply 140, posted (1 year 6 months 3 weeks 6 days 6 hours ago) and read 10415 times:
Support Airliners.net - become a First Class Member!

Quoting Stitch (Reply 142):
Boeing already isolated it to a bad production batch.

To account for the ANA and UA a/c? If so, whew!


User currently offlineRickNRoll From Afghanistan, joined Jan 2012, 841 posts, RR: 0
Reply 141, posted (1 year 6 months 3 weeks 6 days 5 hours ago) and read 10440 times:

Quoting Stitch (Reply 126):
Well to be honest, the current PoS containment system has proven itself "fail safe" because JA804A made a safe and controlled landing. And I have seen nothing that says if JA829J had been in the air it would not have been able to make a safe landing within 180 minutes of a diversion point (the current limit per the JCAB for Japanese carriers).

The NTSB said they weren't happy that flammable electrolyte escaped, or the heat generated, or the fumes. They clearly felt there was an unreasonable risk. Boeing has come up with a much improved containment system that addresses all these issues and appears to be much better suited for the requirements. FWIW, it looks like it addresses all the issues I had with the current containment system, which did not have a pressure release or contents release system that operated in a planned manner.


User currently offlineRickNRoll From Afghanistan, joined Jan 2012, 841 posts, RR: 0
Reply 142, posted (1 year 6 months 3 weeks 6 days 2 hours ago) and read 10102 times:

From the report.

"D.3.2 Functional Hazard Assessment:
Boeing performed a functional hazard assessment (FHA) as part of their evaluation of the 787-8
Electrical Power System Safety. The FHA was performed to determine the potential hazards that
various failuresof electrical system components could introduce to the airplane and its
occupants. The functional hazard assessment identified and classified, pursuant to the
guidance in AC 25.1309-1A, two hazards associated with the main and APU lithium-ion
battery: “battery vents smoke/fire,” which was classified as catastrophic,12 and “battery vent
and/or smoke (without fire),” which was classified as hazardous.13
On the basis of the results of the functional hazard assessment, Boeing defined failure and
mitigation requirements for the main and APU lithium-ion battery; three of the requirements
related to smoke, gas, and electrolyte release are shown in table 2.
Table 2 Battery/Battery Charger Failure Detection/Mitigation Requirements
Requirement Description of Requirement
1 The battery shall have a probability of less than 1 x 10-7 for gas emission.
2 The battery shall have a probability of less than 1 x 10-7 for smoke emission.
3 Battery shall be designed to prevent spilling flammable fluid, a hazardous
event with occurrence with a probability of less than 10-9
."

According to this, the existing containment did not meet the special requirements, even if there was no plane crash.


User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 143, posted (1 year 6 months 3 weeks 6 days 2 hours ago) and read 10093 times:
Support Airliners.net - become a First Class Member!

Quoting RickNRoll (Reply 144):
The NTSB said they weren't happy that flammable electrolyte escaped, or the heat generated, or the fumes.

And they were right to be unhappy. I'm unhappy about leaking electrolyte and flames, even though I'd fly on a 787-8 tomorrow JNB-PER.

But in all their statements, the NTSB have not even implied that if the battery had let go at FL350 mid-Pacific, JL8 was at risk of crashing. And considering how strong their wording has been on everything related to this incident, if they believed it could have (much less would have), they'd not have been shy saying so.



Quoting RickNRoll (Reply 144):
They clearly felt there was an unreasonable risk.

Personally, I think the NTSB and the FAA might have been "spooked" by the number of incidents with the electrical system of the 787 over a relatively short period of time. The FAA was planning to review their certification process of the 787's electrical system before NH692 so when NH and JL both grounded the plane, they did so because they were afraid if they didn't and a 787 suffered an accident, they'd be pilloried before Congress and the US press.

But that decision is air over the wing at this point and one not worth arguing about in these threads. The plane's parked so the goal now should be - and appears to be - to make it safer should things go wrong as well as reduce the chance of things going wrong.

[Edited 2013-03-07 18:32:43]

User currently offlineblrsea From India, joined May 2005, 1423 posts, RR: 3
Reply 144, posted (1 year 6 months 3 weeks 6 days ago) and read 9879 times:

Seattle times report on NTSB findings. Says there was no damage to primary structures of the aircraft, only secondary structures. Also says that there was no end to end test of the battery including the charger/BCU. Also has more info on how the firefighters fought the fire in Boston.

An interesting read anyway...

NTSB report shows Boeing’s battery analysis fell short

Quote:
...
Among the findings are that Boeing mistakenly ruled out any potential causes of a battery fire other than an overcharge and failed to predict the battery’s erratic behavior on the day of the fire.
...
The assessment was done at two levels: The subcontractors — Thales of France, battery maker GS Yuasa of Japan, and Securaplane of Tucson, Ariz., which designed and built the battery charging unit (BCU) system — focused on potential failures of their pieces of the system.

Boeing reviewed the supplier assessments, but it also took a more integrated look from the airplane level, including a safety assessment of the entire electrical power system and with a specific look at “lithium-ion battery cell failure modes.”

The NTSB report seems to question the thoroughness of the testing done by Thales and Securaplane.
...
...
“None of the Thales documents described a complete life-cycle of tests,” the report states. “No records have been seen that documented the performance of the individual Li-ion battery cells in testing that involved a battery/BCU set or in a complete Model 787 airplane.”
...
...
After locating the fire inside the electronics bay in the belly of the airplane, firefighters entered the compartment through dense smoke and applied shots of Halotron fire extinguisher to the battery.

Lt. David Hoadley of the ARFF unit reported that “it seemed like the fire did not want to go out, it kept rekindling.”

Then the battery, in Monroe’s words, “exploded.”

“Capt. Munroe heard the battery hissing still and pushing white smoke or steam. There was liquid sizzling over the sides of the battery and still heavy smoke conditions. ... The battery continued to hiss before exploding.”

Monroe related that “he felt something hit him in the neck while he was in the airplane,” and he was sent out for medical treatment. “Something had burned his neck.”

Firefighters attempted to remove the battery from the jet, but found that the “quick disconnect” mechanism Boeing had included to allow mechanics to take out the battery for maintenance was “melted and un-recognizable” and a metal plate was preventing access.

The firefighters cut away the metal plate, severed the battery wires, then “pried the battery loose with hydraulic spreaders and removed it.”
...
...
NTSB investigators found no heat damage to any primary airplane structure — that is, any part of the airframe critical to flight.

Only the floor panel and carbon fiber floor support material, which are considered to be secondary structure, “were found to be heat damaged beneath where the APU battery had been installed.”
...


User currently offlineBoeingVista From Australia, joined Jan 2009, 1581 posts, RR: 3
Reply 145, posted (1 year 6 months 3 weeks 5 days 23 hours ago) and read 9707 times:

Quoting Stitch (Reply 146):
But in all their statements, the NTSB have not even implied that if the battery had let go at FL350 mid-Pacific, JL8 was at risk of crashing. And considering how strong their wording has been on everything related to this incident, if they believed it could have (much less would have), they'd not have been shy saying so.

Disingenuous Stitch, as you know the NTSB interim report is a factual report, it does not speculate about anything outside of the actual incident.



BV
User currently offlineseahawk From Germany, joined May 2005, 1069 posts, RR: 0
Reply 146, posted (1 year 6 months 3 weeks 5 days 21 hours ago) and read 9421 times:

So in the BOS incident the battery did also release flammable electrolytes into the avionics compartment. Not good, as both incidents now fall into the most serious failure case laid out by the FAA. One that should have a probability of 10-9 to happen. Without a root cause found, it is now likely to be said that the requirements are not met by the current design.

This does not sound like there will be a easy and quick solution.


User currently offlineRickNRoll From Afghanistan, joined Jan 2012, 841 posts, RR: 0
Reply 147, posted (1 year 6 months 3 weeks 5 days 21 hours ago) and read 9460 times:

I think the Seattle Times summed it up in one paragraph.

"The safety agency’s interim report shows Boeing mistakenly ruled out any potential causes of a battery fire other than an overcharge and failed to predict the battery’s erratic behavior on the day of the fire". They want things to be better understood and more predictable, like the rest of the risks that are managed on a plane.


User currently offlineblueflyer From United States of America, joined Jan 2006, 4019 posts, RR: 2
Reply 148, posted (1 year 6 months 3 weeks 5 days 20 hours ago) and read 9329 times:
Support Airliners.net - become a First Class Member!

I'll admit I haven't followed every thread post-by-post because the level is often too technical for me, so apologies if my questions have been asked and answered previously.

Based on the summary of the NTSB report and articles from the Seattle-Times and the Guardian...

Do we know which company was responsible for testing together batteries and their charging units? Are there regulations that designate a responsible entity, or is it up to Boeing to choose someone, possibly itself, to conduct that test?

If the NTSB plans on conducting hearings next month on the batteries and on the certification of the battery system, I don't suppose 787s will return in service in April as a newspaper (can't recall which) claimed Qatar Airways CEO Al Baker was told by Boeing?



I've got $h*t to do
User currently offlinekeegd76 From UK - Northern Ireland, joined Aug 2009, 108 posts, RR: 0
Reply 149, posted (1 year 6 months 3 weeks 5 days 19 hours ago) and read 9257 times:
Support Airliners.net - become a First Class Member!

Quoting blrsea (Reply 147):

“None of the Thales documents described a complete life-cycle of tests,” the report states. “No records have been seen that documented the performance of the individual Li-ion battery cells in testing that involved a battery/BCU set or in a complete Model 787 airplane.”

When they talk about a Model 787 aircraft are we talking about a full-scale mock-up?

If full-scale would Thales have had access to such a thing?



Nothing comes down faster than a VTOL aircraft upside down.
User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2241 posts, RR: 5
Reply 150, posted (1 year 6 months 3 weeks 5 days 18 hours ago) and read 9109 times:

Crossreading the report the following points are useful to clarifiy some of the topics we have discussed here:

Page 11: The list of events on the timescale shows that:
1. A drop of voltage over the battery happened in parallel to the battery starting to draw 44-45 Amperes. This means that within the battery there was not a full but a partial shortcut. This could have been a failure in one cell.

2. This event lasted the first time for some seconds.

3. A second drop of voltage happened about 25 seconds later, this time down to 0 volt. Zero volt and no high currents (see point 4.) are very strange, and from my point of view can only mean, that either the battery had a shortcut across all cells very close to the cells or that the cables and connectors must have been somehow disconnected (theoretically there are further failure modes like interupted voltage sensing, but they are not likely). The later of the two is not plausible, because in that case the battery itself would just have stayed idle and cold. So there was a full shortcut over all cells in very close approximity to the cells itself. I can not imagine how that could have happened, but the data suggests it. You can only get 0 volts across that battery by shorting it with something very thick from iron (because the internal resistance of such a battery is very low, the load that causes the voltage to drop to 0 must have extremely low resistance). In that case current would be collosal. The shorting would have to be between the battery and the current measuring point (see page 8) and be across the two main conductors.

Also noteworthy is that the second time we can rule out a failure in one cell only. Because a shortcut in one cell would not be enough to quickly let drop the overall voltage to 0.

Finally a drop to 0 volts was also reported from the ANA incident.

4. No high currents into the battery the second time (at the measuring point). Even moderate ouflowing current for some short periods when the battery quickly returned to almost full voltage for some moments. That means probably that on the left side of the current measurement point there was no actively controlled voltage anymore (by the battery charger). There is no info whether the battery charger did disconnect. There seems to have been a moderate ohmic load (because of the moderate outflowing current during the short times the battery was able to reestablish a reasonable voltage).

5. Less than 10 seconds later the APU controller and aftwards the APU went down. So it is confirmed that the APU does not offer an independent safety level in addition to the APU battery. In fact the MTBF of the APU fully depends on the MTBF of the battery, if the battery fails as frequent as observed.

6. After about 40 seconds the APU battery was no longer indicated as failed (though it was). What the heck?


Page 32: Overcharging was the only failure mode Boeing assumed to cause venting with fires. This seems very optimistic (and almost ignorant) in the light of known failure modes of such a battery. Real world events have rendered those assumptions as fully void.

Summary:
There seem to be erratic full shortcuts inside that battery. The shortcuts draw the high currents that start destroying the cells. There is no indication that the failures have been induced from the outside (like abnormal high voltage applied to the battery).


User currently offlineBoeingVista From Australia, joined Jan 2009, 1581 posts, RR: 3
Reply 151, posted (1 year 6 months 3 weeks 5 days 17 hours ago) and read 8976 times:

Quoting rheinwaldner (Reply 153):

Page 32: Overcharging was the only failure mode Boeing assumed to cause venting with fires. This seems very optimistic (and almost ignorant) in the light of known failure modes of such a battery. Real world events have rendered those assumptions as fully void.

This is where the FAA looks culpable, did the certifying authority not look at this and say, ok its a battery what about short circuits? And having disproved Boeing's assumptions off the top of their head sent the paperwork back to Boeing to think again or out for a third party opinion.

This is pure negligence by the FAA and if it is indicative of the standard of work applied to the 787 certification process we should all be very worried, no wonder the NTSB is looking at the certification process.



BV
User currently offlinepacksonflight From Iceland, joined Jan 2010, 381 posts, RR: 0
Reply 152, posted (1 year 6 months 3 weeks 5 days 16 hours ago) and read 8796 times:

Quoting rheinwaldner (Reply 153):
5. Less than 10 seconds later the APU controller and aftwards the APU went down. So it is confirmed that the APU does not offer an independent safety level in addition to the APU battery. In fact the MTBF of the APU fully depends on the MTBF of the battery, if the battery fails as frequent as observed.

On top of that the battery smoke venting failed when the APU shut down.

Looks like the 787 needs a new battery to power the battery failure system......


REUTERS: "Among the report's findings: a system designed to vent smoke outside the plane during a battery fire failed to function because it lacked power after the battery caught fire. The system's auxiliary power unit (APU), a gas-driven engine in the tail of the plane, also was shut off at the time, and the battery is used to start that system."

The real question is how is this going to affect the proposal Boeing put forward on Feb 22.??


User currently offlinePlaneInsomniac From Canada, joined Nov 2007, 678 posts, RR: 0
Reply 153, posted (1 year 6 months 3 weeks 5 days 15 hours ago) and read 8635 times:

So, are we talking about a quadruple failure now? Battery fire + venting failure + APU shutdown + faulty indications in the cockpit?

If this isn't a recipe for disaster, I don't know what is.



Am I cured? Slept 5 hours on last long-haul flight...
User currently offlinerobffm2 From Germany, joined Dec 2006, 1117 posts, RR: 0
Reply 154, posted (1 year 6 months 3 weeks 5 days 15 hours ago) and read 8601 times:

Quoting PlaneInsomniac (Reply 156):
So, are we talking about a quadruple failure now? Battery fire + venting failure + APU shutdown + faulty indications in the cockpit?

If this isn't a recipe for disaster, I don't know what is.

Yes, doesn't look good.

And I would guess that before the planed NTSB hearing later this month the FSA will not move at all.


User currently offlineBoeingVista From Australia, joined Jan 2009, 1581 posts, RR: 3
Reply 155, posted (1 year 6 months 3 weeks 5 days 15 hours ago) and read 8487 times:

Quoting robffm2 (Reply 157):

And I would guess that before the planed NTSB hearing later this month the FSA will not move at all.

Yes the fire box proposal only deals with the venting failure nothing else, how can the FAA approve return to flight when the other issues remain?

The whole fault tree needs redoing, the whole certification program needs to be looked at again. Time to pull the 787's airworthiness certificate.



BV
User currently offlineNAV20 From Australia, joined Nov 2003, 9909 posts, RR: 36
Reply 156, posted (1 year 6 months 3 weeks 5 days 14 hours ago) and read 8470 times:

Quoting robffm2 (Reply 157):
And I would guess that before the planed NTSB hearing later this month the FSA will not move at all.

Looks like the opposite is more likely:-

"U.S. safety regulators are poised to approve within days a plan to allow Boeing to begin flight tests of the 787 Dreamliner with a fix for its volatile batteries, a critical step toward returning the grounded aircraft to service, two sources familiar with the matter said on Wednesday.

"The Federal Aviation Administration is expected to sign off on a "certification plan" allowing Boeing to carry out the flight tests........"


http://articles.chicagotribune.com/2...ghts-battery-fire-battery-problems



"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
User currently offlineStitch From United States of America, joined Jul 2005, 31055 posts, RR: 87
Reply 157, posted (1 year 6 months 3 weeks 5 days 14 hours ago) and read 8334 times:
Support Airliners.net - become a First Class Member!

Quoting blueflyer (Reply 151):
If the NTSB plans on conducting hearings next month on the batteries and on the certification of the battery system, I don't suppose 787s will return in service in April as a newspaper (can't recall which) claimed Qatar Airways CEO Al Baker was told by Boeing?

The NTSB does not have any authority over the grounding so the FAA could lift it before the hearings. That being said, the FAA looks to be proceeding cautiously on lifting the grounding and it could well be after the hearings that happens -- NAV20's link notes they look to be ready to allow Boeing to resume test flights to prove their suggested fix is going to work, but that will likely involve many weeks, if not months.



Quoting BoeingVista (Reply 154):
This is where the FAA looks culpable, did the certifying authority not look at this and say, ok its a battery what about short circuits? And having disproved Boeing's assumptions off the top of their head sent the paperwork back to Boeing to think again or out for a third party opinion.

During the certification and testing phase, Boeing did induce short-cirtcuits in individual cells by puncturing them with nails.

What Boeing appears to not have predicted was severe under-volatges and capacity draws nor their effect on the battery cells.



Quoting PlaneInsomniac (Reply 156):
So, are we talking about a quadruple failure now? Battery fire + venting failure + APU shutdown + faulty indications in the cockpit? If this isn't a recipe for disaster, I don't know what is.

It is a failure tree applicable only to ground operations since the APU was the sole active power source for the aircraft (no ground power was connected). When the APU battery failed, it took down the APU which would have meant the Ship's Battery was all that was left and in such a scenario, that battery only provides power to certain systems. If the plane was connected to ground power and not just depending on the APU, I would think that would have provided proper operations once the APU went offline.

And if the fire had happened in flight and taken down the APU, you still would have had four engine generators supplying power. And they would be backed-up by the RAT.

[Edited 2013-03-08 06:28:32]

User currently offlineRickNRoll From Afghanistan, joined Jan 2012, 841 posts, RR: 0
Reply 158, posted (1 year 6 months 3 weeks 5 days 14 hours ago) and read 8318 times:

Quoting NAV20 (Reply 159):

I guess it is how you define a 'return to flight'. I think the meaning is, not grounded. Flight testing of course has to happen, otherwise it could never get back in the air for general use.


User currently offlineBoeingVista From Australia, joined Jan 2009, 1581 posts, RR: 3
Reply 159, posted