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FAA Grounds 787 Part 12

Fri Mar 01, 2013 8:11 am

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.
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rcair1
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FAA Grounds 787 Part 12

Fri Mar 01, 2013 2:16 pm

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.
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FAA Grounds 787 Part 12

Fri Mar 01, 2013 2:28 pm

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]
 
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FAA Grounds 787 Part 12

Fri Mar 01, 2013 3:18 pm

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.
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mjoelnir
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FAA Grounds 787 Part 12

Fri Mar 01, 2013 6:58 pm

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]
 
rcair1
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FAA Grounds 787 Part 12

Fri Mar 01, 2013 11:54 pm

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.
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FAA Grounds 787 Part 12

Fri Mar 01, 2013 11:56 pm

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.
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 2:36 am

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.
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 3:57 am

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?
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mjoelnir
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 6:28 am

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.
 
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 6:33 am

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.
 
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 1:23 pm

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]
 
mjoelnir
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 1:54 pm

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]
 
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 2:39 pm

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).
 
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 2:53 pm

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!  
 
mjoelnir
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 4:57 pm

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.
 
mjoelnir
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 5:29 pm

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]
 
XT6Wagon
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 6:43 pm

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.
 
Wisdom
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 7:04 pm

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.
 
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 8:08 pm

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,
 
airtechy
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 8:39 pm

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.
 
Wisdom
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 8:54 pm

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]
 
mjoelnir
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 9:44 pm

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.
 
Wisdom
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FAA Grounds 787 Part 12

Sat Mar 02, 2013 11:37 pm

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/
 
Wisdom
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 12:56 am

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.
 
BoeingVista
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 3:11 am

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
 
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par13del
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 3:53 am

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?
 
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7BOEING7
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 4:19 am

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.
 
CaliAtenza
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 5:19 am

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.
 
sweair
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 10:19 am

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?
 
Wisdom
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 10:37 am

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.
 
rheinwaldner
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 1:25 pm

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.
 
2175301
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 3:45 pm

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,
 
Wisdom
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 4:12 pm

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.

Top
 
2175301
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 5:55 pm

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,
 
Wisdom
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 10:37 pm

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]
 
RickNRoll
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FAA Grounds 787 Part 12

Sun Mar 03, 2013 11:39 pm

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.
 
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lightsaber
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 12:01 am

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
"They did not know it was impossible, so they did it!" - Mark Twain
 
777ER
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 2:13 pm

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
Head Forum Moderator
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seahawk
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 2:39 pm

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.
 
AeroWesty
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 4:00 pm

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
 
rcair1
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 6:03 pm

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
 
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lightsaber
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 6:19 pm

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
"They did not know it was impossible, so they did it!" - Mark Twain
 
servantleader
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 7:11 pm

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
 
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7BOEING7
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 8:11 pm

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.
 
art
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 8:25 pm

(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?
 
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KarelXWB
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 8:30 pm

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
Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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FAA Grounds 787 Part 12

Mon Mar 04, 2013 9:06 pm

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.
You are 100 times more likely to catch a cold on a flight than an average person!
 
mjoelnir
Posts: 3922
Joined: Sun Feb 03, 2013 11:06 pm

FAA Grounds 787 Part 12

Mon Mar 04, 2013 10:44 pm

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.
 
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par13del
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Joined: Sun Dec 18, 2005 9:14 pm

FAA Grounds 787 Part 12

Mon Mar 04, 2013 11:21 pm

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.

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