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Topic: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-14 02:06:46 and read 29736 times.

Excerpts:

"Japanese airline ANA Holdings said it had found an electrical wiring problem in the fire extinguishers of the engines of three of its Boeing Co Dreamliner jets."

"The airline, which operates the world's biggest fleet of the Boeing 787 jets, is investigating whether the faulty wiring would have caused the extinguisher to malfunction in case on an engine fire."

"After ANA reported the fault, rival Japan Airlines turned back a 787 jet en route to Helsinki to check the fire extinguisher wiring. JAL is now conducting checks on all ten of its 787s, a spokesman for the airline said."

Full story at http://www.reuters.com/article/2013/...pe=RSS&feedName=companyNews&rpc=43

The challenges continue...

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: AA737-823
Posted 2013-08-14 02:25:43 and read 29632 times.

This begs some questions.
IF the wiring was bad (and it evidently was), then HOW could the detector loops and extinguishers pass their tests, performed at the beginning of each flight day, yet still not work properly?

Methinks this "news" may be a hasty jump to a conclusion.

It just doesn't add up; if you push the test button to test squib continuity, and it passes the test, then... there should NOT be anything further to go wrong.

We need more details on this, before we can make any educated guesses as to what's wrong.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: planewasted
Posted 2013-08-14 02:46:22 and read 29460 times.

Quoting AA737-823 (Reply 1):
It just doesn't add up; if you push the test button to test squib continuity, and it passes the test, then... there should NOT be anything further to go wrong.

The last thing in the extinguisher chain is never tested, the actual use of the extinguishers. But I agree, this may very well not be serious at all.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: larshjort
Posted 2013-08-14 03:00:10 and read 29293 times.

Quoting planewasted (Reply 2):

The last thing in the extinguisher chain is never tested, the actual use of the extinguishers. But I agree, this may very well not be serious at all.

No, but all the wiring is tested, there is not a piece of wiring going to the extinguisher that are not tested.

/Lars

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbored
Posted 2013-08-14 03:18:09 and read 29145 times.

Quoting AA737-823 (Reply 1):
IF the wiring was bad (and it evidently was), then HOW could the detector loops and extinguishers pass their tests, performed at the beginning of each flight day, yet still not work properly?

Methinks this "news" may be a hasty jump to a conclusion.
Quoting larshjort (Reply 3):
No, but all the wiring is tested, there is not a piece of wiring going to the extinguisher that are not tested.

"An electrical wiring problem" doesn't have to mean that the wiring is mis-connected or un-connected. The circuit could be correctly connected but still be problematic. It could, for example, be a problem with incorrect guage of wire, incorrect type of insulation, incorrect routing, missing protection 'grommets' when routing through things, etc. etc.


Quoting AA737-823 (Reply 1):
We need more details on this, before we can make any educated guesses as to what's wrong.

Absolutely. Unless, and until, we get more details, we're only going to be stabbing in the dark. Might be trivial, might be major. Right now we haven't got a clue. Bit ominous that JAL turned a flight back, though.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Grisee08
Posted 2013-08-14 04:05:44 and read 28904 times.

...And the Saga continues.

With all the news about the 787, I am wondering 1 of 2 things.

1.) After the current major problems that have occurred, are airlines scared of every little thing?
or
2.) After facing several delays, and having to compensate airlines, did Boeing finally rush this into production and assume they could take care of the problems later on and chalk it up to "Teething Problems?"

I would like to think and say it's number 1. For one, I doubt Boeing would ever EVER do anything like that, and 2, it is somewhat normal for airlines to go over new types with a fine tooth comb, and point out what was done right, and what was done wrong. If this were an article about a 777, I doubt it would have even made news, but the fact that it was 787 automatically triggered NEWS ALERT.

What say you?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: flood
Posted 2013-08-14 04:26:05 and read 28764 times.

According to Bloomberg:

"ANA found improper wiring for the fire-suppression system on a Dreamliner before it was to depart from Tokyo’s Haneda airport today, spokeswoman Megumi Tezuka said by phone. The faulty wiring activates the wrong fire extinguisher in the event of a fire in one of the two engines, she said, adding the defect occurred during the manufacturing process."

http://www.bloomberg.com/news/2013-0...ners-as-jal-plane-scraps-trip.html

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: RedChili
Posted 2013-08-14 04:31:32 and read 28712 times.

Quoting AA737-823 (Reply 1):
IF the wiring was bad (and it evidently was), then HOW could the detector loops and extinguishers pass their tests, performed at the beginning of each flight day, yet still not work properly?

According to Flightglobal, which also has the story, the wires were crossed so that if a fire started in the right engine, and the pilots would press the button to extinguish the fire in the right engine, the LEFT engine fire extinguisher would go off. So, it seems that everything worked properly, except for this tiny problem, which would not matter much unless there's a real fire in one of the engines...

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbored
Posted 2013-08-14 04:38:09 and read 28606 times.

Quoting RedChili (Reply 7):
which would not matter much unless there's a real fire in one of the engines.

At which point, it would then matter a lot.

I can't help wondering whether Boeing might have been pushing their engineers just a little too hard on the production lines to get frames out of the door quickly.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-14 04:38:24 and read 28605 times.

We are hearing a lot about electrical issues on the 787 because it has a lot of focus. My question is how often are similar issues found on other (relatively) new planes?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbored
Posted 2013-08-14 04:45:01 and read 28525 times.

Quoting StTim (Reply 9):
We are hearing a lot about electrical issues on the 787 because it has a lot of focus. My question is how often are similar issues found on other (relatively) new planes?

Issues like this happen on all aircraft types. Mistakes get made regardless of aircraft type or manufacturer. They tend to be a bit more common on new types as people get used to building and maintaining them.

I suspect we're also seeing a slightly higher rate of electrical issues on the 787 partly because there's so much more electrical stuff to have issues with.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: planewasted
Posted 2013-08-14 04:46:19 and read 28510 times.

What happens if you discharge the fire extinguishers in a working engine?

Imagine the scenario:
1. Indicated engine fire in #1.
2. #1 shut down
3. extinguishers discharged
4. #2 goes down because of the extinguishers

[Edited 2013-08-14 04:46:58]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: BoeingVista
Posted 2013-08-14 04:51:20 and read 28467 times.

Quoting RedChili (Reply 7):
which would not matter much unless there's a real fire in one of the engines...

Oh, so only slightly potentially fatal them..

Quoting planewasted (Reply 11):
ine the scenario:
1. Indicated engine fire in #1.
2. #1 shut down
3. extinguishers discharged
4. #2 goes down because of the extinguishers


The wrong engine being shut down has caused fatal accidents in the past for example a British Midland 737-400 which crashed in Kegworh in 1989.

[Edited 2013-08-14 04:57:46]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Tristarsteve
Posted 2013-08-14 04:52:46 and read 28437 times.

Quoting planewasted (Reply 11):
What happens if you discharge the fire extinguishers in a working engine?

They do not discharge in an engine, they discharge in the space around the engine and under the cowlings.
To put out a fire in an engine, you turn the fuel off.
Probably nothing would happen, except the other engine would continue to burn.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-14 04:54:40 and read 28381 times.

Quoting Speedbored (Reply 10):
Issues like this happen on all aircraft types. Mistakes get made regardless of aircraft type or manufacturer. They tend to be a bit more common on new types as people get used to building and maintaining them.

I suspect we're also seeing a slightly higher rate of electrical issues on the 787 partly because there's so much more electrical stuff to have issues with

That is what I suspected.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: PHX787
Posted 2013-08-14 08:06:05 and read 27552 times.

Quoting Grisee08 (Reply 5):
1.) After the current major problems that have occurred, are airlines scared of every little thing?

NH, JL, the Japanese media, and the Japanese public sure as hell are. But some people still have a lot of faith in the 787. But I was watching a news report about the 787 recently, and people sure as hell reported being concerned.

When you have a worldwide grounding, which includes a chunk of your nation's airlines' fleets, yeah I'd understand it.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: wingman
Posted 2013-08-14 08:12:14 and read 27471 times.

I wonder also whether having wiring checked every single millimeter on a 777, 330, 748, or 380 wouldn't find such issues on a routine basis.

Who makes these fire suppression systems? Seems like quite the cock up to instruct the left to put out the right when putting out fires in places where instructed is the single overriding mission.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: spacecadet
Posted 2013-08-14 08:19:17 and read 27392 times.

Quoting Grisee08 (Reply 5):
1.) After the current major problems that have occurred, are airlines scared of every little thing?

Improperly wired fire extinguishers that would go off in the wrong engine are not a "little thing".

Think of it from the POV of the pilots. You have an engine fire. You pull the fire handle. As far as you know, nothing happens. The fire continues to burn. You're not going to start randomly pulling other levers and switches; if the left engine is on fire, you follow the checklist and pull the left fire handle. The last thing you want in a situation like that is confusion in the cockpit, and a delayed (or nonexistent) fire response because to the pilots, the fire suppression system was just ineffective. All they'd be able to do would be to land as quickly as possible with the engine potentially still on fire and an evacuation on the tarmac (from a burning plane) that *will* lead to injuries, at best.

This is a passenger safety issue.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 08:25:34 and read 27329 times.

That it's been detected on a 787 is likely why it's been reported in the media, but regardless of the aircraft, it's a serious issue if it results in the incorrect engine extinguisher being discharged.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: TheRedBaron
Posted 2013-08-14 08:32:24 and read 27269 times.

I really think Fire is a word that should not be used anywhere near a 787, do all the problems in this plane are fire related... man I can believe such a bad luck.
TRB

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sonomaflyer
Posted 2013-08-14 08:49:56 and read 27107 times.

Quoting TheRedBaron (Reply 19):
man I can believe such a bad luck.

This has nothing to do with luck. Crossing the wiring on a key safety component is a major safety issue and a sign that Boeing or the engine manufacturer were cutting corners. Expect to see an air worthiness directive instructing 787 operators to inspect and validate the fire extinguisher wiring on their a/c.

Depending on who actually performed this wiring work, its either going to apply to all 787s or RR equipped 787s since ANA has RR engines.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 08:51:51 and read 27096 times.

Quoting sonomaflyer (Reply 20):
This has nothing to do with luck. Crossing the wiring on a key safety component is a major safety issue and a sign that Boeing or the engine manufacturer were cutting corners.

If this is the case on every 787 delivered to date, then yes.

If it's only on the one NH plane, then I put it down to human error.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-14 08:59:09 and read 27005 times.

Human error on one frame or systematic error is almost irrelevant.

It should have been found during testing. It is a safety issue. I cannot see that it is the engine manufacturer that is to blame. Someone has wired the switches the wrong way round in the cockpit. Assuming that these are directly wired safety systems.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 09:02:45 and read 26974 times.

Quoting wingman (Reply 16):
Who makes these fire suppression systems? Seems like quite the cock up to instruct the left to put out the right when putting out fires in places where instructed is the single overriding mission.

It should not matter who made it, since they're almost certainly not in control of the wiring from the system back to the cockpit controls that initiate it.


Quoting StTim (Reply 22):
Human error on one frame or systematic error is almost irrelevant.

It should have been found during testing.

The only "test" for such an error is to actually discharge the extinguisher and that is not a normal testing item item since it would require the refurbishment of the engine afterwards.

[Edited 2013-08-14 09:14:36]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: JRenavitz
Posted 2013-08-14 09:04:52 and read 26952 times.

Quoting wingman (Reply 16):
Who makes these fire suppression systems? Seems like quite the cock up to instruct the left to put out the right when putting out fires in places where instructed is the single overriding mission.


I seem to remember seeing a TV program that described a similar situation on the second stage of an early test Saturn V during the Apollo program. States that the signal wire from the onboard computer was wired incorrectly so that when the computer detected a problem with one of the five second stage engines it sent a shutdown signal to another engine as a result. In the end the second stage was operating on three of its five engines, but limped into orbit. This was one of the early unmanned tests of the Saturn V.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: RedChili
Posted 2013-08-14 09:11:13 and read 27778 times.

Quoting Stitch (Reply 21):
If it's only on the one NH plane, then I put it down to human error.

According to Flightglobal, NH found this problem on three planes.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 09:13:59 and read 27802 times.

Quoting RedChili (Reply 25):
According to Flightglobal, NH found this problem on three planes.

Then depending on how many more are found, it could indeed be a design error in the production or change incorporation documentation, which would indeed be a matter of serious concern.

[Edited 2013-08-14 09:15:03]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-14 09:14:57 and read 28273 times.

I don't agree it is the only test to find it.

ANA found it during a routine inspection and I presume they did not fire off the extinguisher.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: brilondon
Posted 2013-08-14 09:15:32 and read 28198 times.

Quoting PHX787 (Reply 15):
NH, JL, the Japanese media, and the Japanese public sure as hell are. But some people still have a lot of faith in the 787. But I was watching a news report about the 787 recently, and people sure as hell reported being concerned.

All the people or just the ones that were interviewed?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 09:16:51 and read 28162 times.

Quoting StTim (Reply 27):
I don't agree it is the only test to find it.

ANA found it during a routine inspection and I presume they did not fire off the extinguisher.

Then it would be helpful to know which airframes these are and how often they've been inspected, for if they're early deliveries with multiple "routine" inspections on them, why did they not find it until now?

Or was there a specific inspection that needed to be performed that allowed the NH maintenance workers to identify there was a wiring problem?

[Edited 2013-08-14 09:45:51]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: mats01776
Posted 2013-08-14 09:17:09 and read 28215 times.

Quoting Stitch (Reply 23):
The only "test" for such an error is to actually discharge the extinguisher and that is not a normal testing item item since it would require the refurbishment of the engine afterwards.

With all due respect, it is one thing for a technician to cross the wires by mistake during a manufacturing process, but it is quite another to have no non-destructive procedure to test whether this crucial safety equipment is wired properly.

The lack of engineering foresight in testability is no excuse for a product defect.

It bothers me greatly that this plane with wiring fault passed the quality control.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 09:23:16 and read 28083 times.

Quoting mats01776 (Reply 30):
With all due respect, it is one thing for a technician to cross the wires by mistake during a manufacturing process, but it is quite another to have no non-destructive procedure to test whether this crucial safety equipment is wired properly.

I would not be surprised if the general test is to confirm continuity of the wire from the discharge switch in the cockpit to the extinguisher system itself. Provided the two are electrically connected, that test is going to return an "OK".

Now I suppose you could design into the system two modules, one that says "I'm the left engine" and another that says "I'm the left discharge switch" and include control and testing logic that requires them to both confirm they're each other so as to prevent a cross-wiring situation where the left extinguisher discharge switch is connected to the right engine extinguisher system, but that adds cost and complexity and increases the size of the fault tree.

Easier and cheaper to just pay attention at installation and QC.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: KarelXWB
Posted 2013-08-14 09:34:30 and read 27839 times.

Quoting StTim (Reply 22):
Human error on one frame or systematic error is almost irrelevant.

While I agree, this is not the first time faulty wiring has been found on the 787:

> December 2011: the FAA found faulty wiring during a routine inspection on an aircraft about to be delivered to ANA
> December 2012: faulty electrical wiring was found on a United and Qatar 787
> January 2013: UA reports problem with wiring near the main batteries on one of its six 787s
> July 2013: incorrect wiring was found around the emergency beacon of some 787s
> August 2013: faulty wiring on 787 engine fire extinguishers

There are more reports of faulty wiring and most of them seems to be found during a routine inspection, so perhaps the quality control on the assembly line should improve?

[Edited 2013-08-14 09:36:36]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: rheinwaldner
Posted 2013-08-14 09:35:07 and read 27821 times.

Quoting Stitch (Reply 23):
The only "test" for such an error is to actually discharge the extinguisher and that is not a normal testing item item since it would require the refurbishment of the engine afterwards.

There are two many other wires that could unintentionally have been crossed to have this stuff untested....

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: mats01776
Posted 2013-08-14 09:38:09 and read 27722 times.

Quoting Stitch (Reply 31):
Now I suppose you could design into the system two modules, one that says "I'm the left engine" and another that says "I'm the left discharge switch" and include control and testing logic that requires them to both confirm they're each other so as to prevent a cross-wiring situation where the left extinguisher discharge switch is connected to the right engine extinguisher system, but that adds cost and complexity and increases the size of the fault tree.


There are much simpler and cheaper solutions.

For example, I have designed wire harnesses for industrial equipment where Channel 1 (e.g. or 'left') and Channel 2 (e.g. or 'right') sensor wire harnesses to have different left-hand-side and right-hand-side connectors. That is, the 'plug' for channel 1 cannot be mated to the 'jack' for channel 2.

It's a common-sense engineering practice in some sectors of electronics industry.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: yeelep
Posted 2013-08-14 09:40:53 and read 27629 times.

It may not be a case of complete loss of extinguishing capabilities. If one bottles squibs are miswired the other bottle will still fire normally, so you would have half the capability.

If it is indeed cross wired at the squibs, it could have being found while checking the bottle pressures. Something as simple as noticing the wiring being preloaded could have been the indication of a problem.

Quoting StTim (Reply 27):

I don't agree it is the only test to find it.

ANA found it during a routine inspection and I presume they did not fire off the extinguisher.

Yes there is a test to confirm the wiring, without discharging the bottle, though it involves disconnecting the wiring from the squibs.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 09:44:37 and read 27544 times.

Quoting mats01776 (Reply 34):
It's a common-sense engineering practice in some sectors of electronics industry.

That would increase the spares costs by having to stock two separate connectors for a common system so I could understand why it's not employed here.

Assuming this was not an issue with previous Boeing Commercial Airplane families, such a system should not be required for the 787. The production and change incorporation documentation should probably be given another look-over to ensure there are no errors about the installation instructions and if that documentation checks out, then a review of the personnel who handled installation on the affected planes should be undertaken to determine if there is a pattern of certain workers making this mistake or if something in the documentation or processes that is confusing the entire workforce performing this specific task.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: yeelep
Posted 2013-08-14 09:46:58 and read 27480 times.

Quoting mats01776 (Reply 34):
There are much simpler and cheaper solutions.

For example, I have designed wire harnesses for industrial equipment where Channel 1 (e.g. or 'left') and Channel 2 (e.g. or 'right') sensor wire harnesses to have different left-hand-side and right-hand-side connectors. That is, the 'plug' for channel 1 cannot be mated to the 'jack' for channel 2.

It's a common-sense engineering practice in some sectors of electronics industry.

You would also have to have two different squibs with different thread size to prevent the left squib being installed in the right position and vice versa.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: DTW2HYD
Posted 2013-08-14 10:01:33 and read 27163 times.

May be 787 will the first aircraft to get "D check on delivery" distinction.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Markam
Posted 2013-08-14 10:21:52 and read 26735 times.

Quoting RedChili (Reply 7):
According to Flightglobal, which also has the story, the wires were crossed so that if a fire started in the right engine, and the pilots would press the button to extinguish the fire in the right engine, the LEFT engine fire extinguisher would go off. So, it seems that everything worked properly, except for this tiny problem, which would not matter much unless there's a real fire in one of the engines...

If that is so, then I've got a bridge to sell you... the only tiny problem is that I do not actually own it, but that would not matter much unless you want to re-sell the bridge, would it?    

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 10:24:17 and read 26687 times.

Does anyone have an authoritative idea on how this system is wired on either the 787 or commercial airliners in general?

I'm guessing there is not a single "control wire" running from the discharge handle on the flight deck to the extinguisher squib controller on the engines. Would it be more likely that the discharge handle is wired to some type of aggregator panel in the forward electronic equipment bay and then another wire (or set of wires) carries (carry) the signal (perhaps with others) down to another panel in the wingbox area or aft electronics bay, followed by still another wire (or set of wires) that either go to the engines or the engine control module and then from there to the squib controller?

While at this point we can only speculate, if there are multiple connection points, perhaps the "crossing" happened at one of the downstream connectors? Say if it is in the aft EE bay, the wires were crossed at that panel?

[Edited 2013-08-14 10:25:24]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: czbbflier
Posted 2013-08-14 12:06:46 and read 24880 times.

Quoting BoeingVista (Reply 12):
The wrong engine being shut down has caused fatal accidents in the past for example a British Midland 737-400 which crashed in Kegworh in 1989.

As soon as I read that it was a left / right wiring issue, this is exactly the end result I thought of. Thanks for putting this up, saving me the research time.

Clearly, this is not the first time Boeing has made this error.

Quoting Speedbored (Reply 10):
Issues like this happen on all aircraft types. Mistakes get made regardless of aircraft type or manufacturer. They tend to be a bit more common on new types as people get used to building and maintaining them.

Forgive me- and I am a Boeing fan- but I have never heard of similar "details" like accidental left / right switching on any other airframe manufacturer.

And if it happens on something as crucial as fire extinguisher panels and throttle assemblies, it makes one wonder how many other "little issues" like that lurk behind the blinking lights and twirly knobs. And how often it does happen with other manufacturers.

Meanwhile, if these sorts of mistakes happen because it's a new type of aircraft, that gives nobody any reason ever at all to look forward to a plane that is new to the skies. If anything, those on the assembly line should be extra slow, extra cautious, double and triple-checking to make sure it's right when it's a new model.

* * * * *
Speedbored, I'm sure you're not implying that it's okay that mistakes happen. That may well be a fact. However, there is a normative component to this. I am sure you would concur with me that there is a mandatory rejoinder to what you said- that while mistakes happen it is unacceptable that they do.

Building toward that most basic norm, established procedures need to be in place to ensure that mistakes as basic as this never happen. If procedures like these are not in place, one must ask why.

Pilots are taught to "trust their instruments". Similarly, pilots believe that their controls are similarly trustworthy. How can they not after all?

Because if the controls are not trustworthy, is the plane flyable?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: ER757
Posted 2013-08-14 12:16:12 and read 24712 times.

Quoting KarelXWB (Reply 32):

Agree - sounds like a QA issue at the manufacturer.....OK, putting on my flame suit in 3, 2, 1,   

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 12:17:38 and read 24793 times.

Quoting BoeingVista (Reply 12):
The wrong engine being shut down has caused fatal accidents in the past for example a British Midland 737-400 which crashed in Kegworh in 1989.
Quoting czbbflier (Reply 41):
As soon as I read that it was a left / right wiring issue, this is exactly the end result I thought of.

Clearly, this is not the first time Boeing has made this error.

Captain Hunt's decision to shut down the wrong engine was caused by lack of training on the 737-400's systems and his unfamiliarity with how certain systems operated in comparison to earlier models. He also failed to review his decisions prior to continuing his decent and the cabin crew failed to inform him which engine was showing signs of failure as they assumed he already knew.

It had nothing to do with incorrect wiring (either by design or human error during assembly).



Quoting czbbflier (Reply 41):
Speedbored, I'm sure you're not implying that it's okay that mistakes happen. That may well be a fact. However, there is a normative component to this. I am sure you would concur with me that there is a mandatory rejoinder to what you said- that while mistakes happen it is unacceptable that they do.

Perfection is indeed a nice goal to shoot for, but one that is currently unattainable.

Perhaps at some future point there will be no need to certify new models or upgrades to existing models and Airbus and Boeing will be able to roll planes out of the paint hangar and directly to the delivery center for immediate flyaway by the customer with no need for manufacturer or customer test flights.

But for the moment, s**t happens. The current goal is to make it as unlikely to happen as you can and considering the industry's overall safety record, as well as the safety record of each individual in service model and family, both OEMs are doing a darn good job of meeting that goal.

[Edited 2013-08-14 12:26:12]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: mats01776
Posted 2013-08-14 12:25:51 and read 24534 times.

Quoting Stitch (Reply 36):
That would increase the spares costs by having to stock two separate connectors for a common system so I could understand why it's not employed here.

Actually, it is not necessarily so.

Assuming that the fire extinguishing subsystem has a single "control box" with a "left" socket and a "right" socket that each connect to the #1 engine and #2 engine respectively. The "squib" end of the wiring harness can have a "common" use plug, thus eliminating the need to stock distinct "left" and "right" squibs.

This, of course, assumes that the wiring harness is assembled correctly.

In a modern vehicle design many of the non-emergency, non-critical signals are carried on multiplexed "buses" similar to Ethernet rather than point-to-point wiring.

There the problem of faulty wiring is replaced with a problem of proper identification of modules that are plugged into the bus.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: AirbusA370
Posted 2013-08-14 12:46:12 and read 24212 times.

This reminds me of the A320 crossed sidestick controls at Lufthansa

http://www.flightglobal.com/news/art...-bring-down-lufthansa-a320-130318/

Of course, those incidents show a lack of test procedures. The correct test procedure for the crossed sidestick would be to check if the rudder deflection in the ECAM display is corresponding to the sidestick movement (before that, they looked only for *any* rudder movement)

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Grisee08
Posted 2013-08-14 12:49:36 and read 24079 times.

Quoting spacecadet (Reply 17):

That is a good point, and I honestly didn't mean that the way it came out. I guess I MEANT to ask are airlines going to be checking every little system and big system more frequently than is called for on the 787 to ensure passenger safety. If so, I applaud that decision, but I am disappointed that such a decision had to be made. If a system calls for it to be checked every 500 hours, it should be able to go for 500 hours. It appears to me that airlines may check systems on the 787 slated at 500 hours every 250 hours.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-14 12:52:42 and read 24015 times.

Quoting Stitch (Reply 36):
That would increase the spares costs by having to stock two separate connectors for a common system so I could understand why it's not employed here.

Actually over previous models, there are numerous instances of dis-similar connectors to preclude errors.. this is true in both electrical, hydraulic and oxygen systems .. consider that in a fleet of 5 or more planes the different connectors would not be a substantial parts investment. Further, it would only come into play if one harness was being exchanged for a replacement.. the probability that a damaged harness would be repaired is remote. There is too much of a chance of other damage in removal or age related cracking and chaffing issues.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: justloveplanes
Posted 2013-08-14 12:54:43 and read 23991 times.

Quoting sonomaflyer (Reply 20):
This has nothing to do with luck. Crossing the wiring on a key safety component is a major safety issue and a sign that Boeing or the engine manufacturer were cutting corners. Expect to see an air worthiness directive instructing 787 operators to inspect and validate the fire extinguisher wiring on their a/c.

This sounds more like a Boeing vice a GE or RR issue as it seems it affects both engines, so upstream of them.

ZA004 and ZA005 are both headed to San Bernadino today for concurrent testing (from the 787 production thread). Could this be for testing actual fire extinguisher release? Is there an RR service shop nearby?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: par13del
Posted 2013-08-14 12:56:02 and read 23967 times.

Quoting flood (Reply 6):
"ANA found improper wiring for the fire-suppression system on a Dreamliner before it was to depart from Tokyo’s Haneda airport today, spokeswoman Megumi Tezuka said by phone. The faulty wiring activates the wrong fire extinguisher in the event of a fire in one of the two engines, she said, adding the defect occurred during the manufacturing process."
Quoting RedChili (Reply 7):
According to Flightglobal, which also has the story, the wires were crossed so that if a fire started in the right engine, and the pilots would press the button to extinguish the fire in the right engine, the LEFT engine fire extinguisher would go off. So, it seems that everything worked properly, except for this tiny problem, which would not matter much unless there's a real fire in one of the engines...
Quoting StTim (Reply 22):

It should have been found during testing. It is a safety issue. I cannot see that it is the engine manufacturer that is to blame. Someone has wired the switches the wrong way round in the cockpit. Assuming that these are directly wired safety systems.
Quoting StTim (Reply 27):
ANA found it during a routine inspection and I presume they did not fire off the extinguisher.

So unless this was an a/c just delivered, how exactly did this routine examination turn up a manufacturer defect?
Routine imples an inspection done frequently which may have been done before, was the defect that "hidden" that the OEM and the user could not detect it during pre-delivery testing, certification and normal routine inspections?

Will be interesting to see how many other operators of the a/c dicsover these "crossed wires" and hopefully, Boeing will advise whether it applies to frames not yet delivered.
It does give the basis of a new improvement in the testing of the a/c, how about a small diode light which goes off somewhere in the engine being tested, colour coded to ensure that the right switch is testing the right engine.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: KarelXWB
Posted 2013-08-14 12:59:03 and read 23896 times.

Quoting justloveplanes (Reply 48):
ZA004 and ZA005 are both headed to San Bernadino today for concurrent testing (from the 787 production thread). Could this be for testing actual fire extinguisher release? Is there an RR service shop nearby?

Doubt it, both planes are currently testing the new engine upgrades.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Grisee08
Posted 2013-08-14 14:02:48 and read 22824 times.

I am sort of wanting to fly on a 787 just to check it out, but each time I consider it, I am going more and more towards not doing it at all. I may wait a few years until all the kinks are worked out. I would hate to buy a ticket just to fly on a 787, only to show up and it be replaced with a 767 or 777. Methinks UA will be keeping these birds on more domestic routes than originally planned for a little bit longer.  

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: PITingres
Posted 2013-08-14 14:14:04 and read 22514 times.

Quoting mats01776 (Reply 44):
Assuming that the fire extinguishing subsystem has a single "control box" with a "left" socket and a "right" socket that each connect to the #1 engine and #2 engine respectively...

A rather unjustified assumption, although if true I'll be happy to retract.

Quoting mats01776 (Reply 44):
In a modern vehicle design many of the non-emergency, non-critical signals are carried on multiplexed "buses" similar to Ethernet rather than point-to-point wiring.

There the problem of faulty wiring is replaced with a problem of proper identification of modules

Indeed, and one has to wonder if perhaps the fire extinguisher signals fell into the middle ... "too important" to be left to a network ID, and "not important" enough to be worth engineering as separate L/R incompatible connectors.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbird128
Posted 2013-08-14 14:28:08 and read 22232 times.

Quoting Stitch (Reply 43):
But for the moment, s**t happens

At a quite some rate too   

Maybe the 787 needs Immodium Ultra.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 14:35:46 and read 22144 times.

Quoting Grisee08 (Reply 51):
I am sort of wanting to fly on a 787 just to check it out, but each time I consider it, I am going more and more towards not doing it at all.

I've been on her a number of times with a number of carriers and it's always been a nice ride so hopefully when you do decide to do so, you also will enjoy the experience. My only real complaint is that nobody has yet put a First Class cabin in one.   

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: wingman
Posted 2013-08-14 14:40:37 and read 22006 times.

So aside from a small minority we are agreed that this is a monumental failure of QA testing at Boeing and that the 787 is a flying death machine? I'm glad nothing has changed in the forum over the past three weeks.

Part of me wishes I had the time to explore all diversions, turn backs, and directives affecting every other commercial aircraft model currently in service. I think some of you would do 100% of your travel by donkey henceforth.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airtechy
Posted 2013-08-14 14:50:18 and read 21824 times.

I can think of many ways that this error could have been introduced. My question is .... how did they catch it?  

AT

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-14 15:04:54 and read 21645 times.

Quoting wingman (Reply 55):
So aside from a small minority we are agreed that this is a monumental failure of QA testing at Boeing

A serious QA failure, and it does seem to add to a pattern of QA failures.

Quoting wingman (Reply 55):
and that the 787 is a flying death machine?

No. Agreeing it is a serious issues does not equate to people believing it is a flying death machine, but it does suggest there is a lot of work to be done before it can achieve the same quality reputation as the 777 and all other Boeing products.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: ukoverlander
Posted 2013-08-14 15:29:34 and read 21356 times.

Quoting RedChili (Reply 7):
So, it seems that everything worked properly, except for this tiny problem, which would not matter much unless there's a real fire in one of the engines...

This may be the most optimistic reply I've ever read on Anet......   

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: ukoverlander
Posted 2013-08-14 15:32:20 and read 21271 times.

Quoting Tristarsteve (Reply 13):
Probably nothing would happen, except the other engine would continue to burn.

                 

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: flood
Posted 2013-08-14 16:17:43 and read 20672 times.

Quoting airtechy (Reply 56):
My question is .... how did they catch it?

JA804A went in for cabin reconfiguration on July 28th and perhaps they carried out some parallel inspections. Just a guess. The frame went back into service today.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: KELPkid
Posted 2013-08-14 17:52:24 and read 19648 times.

Wasn't there a 737-400 that crashed because the fire detection loops were miswired (e.g. #1 engine loop was wired to #2 fire indicator, #2 engine loop was wired to #1 fire indicator) and the crew pulled the wrong fire bottle based on this info?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: COEWR787
Posted 2013-08-14 18:07:07 and read 19457 times.

Is Boeing having a somewhat serious quality control problem in the 787 program? Or are such snafus par for the course?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: VirginFlyer
Posted 2013-08-14 18:58:27 and read 18932 times.

Quoting czbbflier (Reply 41):
Speedbored, I'm sure you're not implying that it's okay that mistakes happen. That may well be a fact. However, there is a normative component to this. I am sure you would concur with me that there is a mandatory rejoinder to what you said- that while mistakes happen it is unacceptable that they do.

My understanding of human factors or human performance (and I'm not claiming a particularly deep understanding compared to your average pilot) is that taking an attitude of "errors are unacceptable and must be eliminated" produces worse safety outcomes than one of "errors are an inevitible result of human interactions, and appropriate systems and checks need to be in place to detect and manage these errors, and to reduce the liklihood of them being made in the first place".

Quoting KELPkid (Reply 61):
Wasn't there a 737-400 that crashed because the fire detection loops were miswired (e.g. #1 engine loop was wired to #2 fire indicator, #2 engine loop was wired to #1 fire indicator) and the crew pulled the wrong fire bottle based on this info?

No. See below:

Quoting Stitch (Reply 43):
Quoting BoeingVista (Reply 12):
The wrong engine being shut down has caused fatal accidents in the past for example a British Midland 737-400 which crashed in Kegworh in 1989.
Quoting czbbflier (Reply 41):
As soon as I read that it was a left / right wiring issue, this is exactly the end result I thought of.

Clearly, this is not the first time Boeing has made this error.

Captain Hunt's decision to shut down the wrong engine was caused by lack of training on the 737-400's systems and his unfamiliarity with how certain systems operated in comparison to earlier models. He also failed to review his decisions prior to continuing his decent and the cabin crew failed to inform him which engine was showing signs of failure as they assumed he already knew.

It had nothing to do with incorrect wiring (either by design or human error during assembly).

V/F

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-14 20:39:39 and read 18102 times.

Quoting COEWR787 (Reply 62):
Is Boeing having a somewhat serious quality control problem in the 787 program?

Every single issue with the 787 is made public because of the media (and forum) focus on the plane, so it definitely gives the current impression of having serious QC issues based on the number of media reports and forum threads vis-a-vis other designs currently in service.

Whether this perception is also fact is not so clear.

Dispatch percentages have been posted for earlier models and families at similar points in their entry into service, those figures do not break down as what caused the failure to dispatch on time and whether or not that failure was caused by QC issues.

Wiring has been an issue with previous Boeing families and models. I recall during a documentary on the 747-400 that the first plane was said to have been rolled out with much of it's wiring still needing to be properly installed. And tdscanuck noted the 777-200 experienced a number of issues early on in her service, including problems with wiring, onboard fire and smoke events, and such. And lightsaber has noted the GE90-7x engines had fuel injectors that failed after two dozen flights.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: 7BOEING7
Posted 2013-08-14 20:40:10 and read 18202 times.

Here is what JAL said on their website:

" For all ten 787s that JAL operates, the inspection was made before the flight and confirmed that there was no defect."

One airplane was recalled inflight:

"JAL received the information today (August 14) that the defect was found in the engine fire extinguishing system wiring on another operator’s 787. JAL started the one-time inspection (all airplanes inspection) of the system. Though JAL413 was cruising at that time, it was decided to return to Tokyo (Narita) for the inspection in consideration of the remaining flight time. The airplane landed at Tokyo (Narita) approx. four hours after takeoff. No defect was found as the result of the inspection. JAL413 re-departed with approx. seven hours delay by another airplane inspected."

The fire bottles are just one of several mechanisms to put out an engine fire -- when the fire handle is pulled the fuel and hydraulics are shut off to the engine and the engine is shutdown. If the fire goes out after pulling the fire handle (most likely event) the fire bottle isn't even used. Interesting question is -- were both fire bottles miss-wired or just one?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: czbbflier
Posted 2013-08-14 21:23:09 and read 17815 times.

Quoting Stitch (Reply 43):
It had nothing to do with incorrect wiring (either by design or human error during assembly).

Thank you. Oddly, that comes as a relief. I don't know how I missed that important fact.

Quoting Stitch (Reply 43):
But for the moment, s**t happens. The current goal is to make it as unlikely to happen as you can and considering the industry's overall safety record, as well as the safety record of each individual in service model and family, both OEMs are doing a darn good job of meeting that goal.

Yes- no argument there.

Quoting VirginFlyer (Reply 63):
My understanding of human factors or human performance (and I'm not claiming a particularly deep understanding compared to your average pilot) is that taking an attitude of "errors are unacceptable and must be eliminated" produces worse safety outcomes than one of "errors are an inevitible result of human interactions, and appropriate systems and checks need to be in place to detect and manage these errors, and to reduce the liklihood of them being made in the first place".

I have no doubt that this is true.

I guess I took my view too far. I agree that the industry's standards are better than most. Populated by human it can still only attain a 'perfection rate' of 99.999999%. So every so often things will fall through the cracks. Pardon my absolutism.

Peace.  

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: LimaNiner
Posted 2013-08-14 21:46:04 and read 17695 times.

Quoting Speedbored (Reply 4):
"An electrical wiring problem" doesn't have to mean that the wiring is mis-connected or un-connected. The circuit could be correctly connected but still be problematic. It could, for example, be a problem with incorrect guage of wire, incorrect type of insulation, incorrect routing, missing protection 'grommets' when routing through things, etc. etc.


There has been a lot of speculation in this thread about what actually happened.

If you've ever worked with Japanese engineers, especially those under pressure to find "quality problems", you will know that they will flag completely ridiculous things -- like inconsistent brightness in LEDs -- as "DOA" problems.

Until we have an official report with exact findings, I would discount this "trouble report" significantly, considering the source.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: jetmech
Posted 2013-08-14 22:43:24 and read 17298 times.

Quoting Tristarsteve (Reply 13):

Pulling out the fire handle prior to twisting for bottle discharge shuts off electrical power and all fluids to an engine doesn't it? I wonder if these functions were cross wired too   .

Quoting Stitch (Reply 23):
The only "test" for such an error is to actually discharge the extinguisher and that is not a normal testing item item since it would require the refurbishment of the engine afterwards.

You could always fire off a squib that is not screwed into a bottle, which would be the definitive test of the wiring routing as well as assuring sufficient current was reaching the squib.

Regards, JetMech

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: seahawk
Posted 2013-08-15 00:17:52 and read 16597 times.

Probably they checked the bottles while the plane was in the dock for cabin up-dates. Or they replaced the bottles and the wrong warning light went on when removing a bottle.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: frigatebird
Posted 2013-08-15 04:02:25 and read 15627 times.

Quoting PHX787 (Reply 15):
Quoting Grisee08 (Reply 5): 1.) After the current major problems that have occurred, are airlines scared of every little thing?NH, JL, the Japanese media, and the Japanese public sure as hell are. But some people still have a lot of faith in the 787

That sounds really bad. I wonder how long NH will keep the '787' on the aircraft.

Quoting sankaps (Reply 57):
A serious QA failure, and it does seem to add to a pattern of QA failures.

Agreed. I'm probably jumping the gun by a mile, but I get the feeling more and more the 787-8 will be a dog, ultimately becoming rather unpopular with airlines, in favor of the 787-9. Which I hope won't have the snags of -8... Not unprecedented: the F100 had quite some persisting issues, but most of them were gone on the F70.

Quoting VirginFlyer (Reply 63):
My understanding of human factors or human performance (and I'm not claiming a particularly deep understanding compared to your average pilot) is that taking an attitude of "errors are unacceptable and must be eliminated" produces worse safety outcomes than one of "errors are an inevitible result of human interactions, and appropriate systems and checks need to be in place to detect and manage these errors, and to reduce the liklihood of them being made in the first place".

Absolutely true.

Quoting Stitch (Reply 64):
Every single issue with the 787 is made public because of the media (and forum) focus on the plane, so it definitely gives the current impression of having serious QC issues based on the number of media reports and forum threads vis-a-vis other designs currently in service. Whether this perception is also fact is not so clear.

A very good point. If this fire extingishing issue was dicovered on another type of airplane, would it have got any publicity at all? But I believe the only way for the 787 program to 'extinguish' these kind of reports, is not having issues so regularly.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Boeing12345
Posted 2013-08-15 05:04:00 and read 15370 times.

Quoting Stitch (Reply 23):
The only "test" for such an error is to actually discharge the extinguisher and that is not a normal testing item item since it would require the refurbishment of the engine afterwards.

Not true. In heavy maintenance a procedure we carried out like this per the AMM:
Disconnect the squib and install a "test box" then activate the appropriate squib switch in the flight deck. The box would measure the amperage and ensure the correct bottle position.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: par13del
Posted 2013-08-15 05:04:12 and read 15352 times.

Quoting seahawk (Reply 69):
Probably they checked the bottles while the plane was in the dock for cabin up-dates. Or they replaced the bottles and the wrong warning light went on when removing a bottle.

I would think if it was that simple it would be something done at the OEM prior to delivery and acceptance by any airline, that simple it should be a mandatory test.
Remember that actually firing off fire bottles is only done when a actual fire occurs, or on a demo frame, its equipment that in regular operations are inspected and always expected to perform.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbored
Posted 2013-08-15 05:51:47 and read 15186 times.

Quoting czbbflier (Reply 41):
Speedbored, I'm sure you're not implying that it's okay that mistakes happen. That may well be a fact. However, there is a normative component to this. I am sure you would concur with me that there is a mandatory rejoinder to what you said- that while mistakes happen it is unacceptable that they do.

Building toward that most basic norm, established procedures need to be in place to ensure that mistakes as basic as this never happen. If procedures like these are not in place, one must ask why.

I'm not implying that it's OK for mistakes to happen. I was simply pointing out the fact that in the real world, mistakes are made. No matter how many policies, checks or procedures you add to a process, there will always be things that will fall through the gaps. People will always have bad days, have periods of in-attention, occasionally be in a hurry, or maybe even get a bit lazy, so mistakes will continue to occur.

If the flying public were aware of how often aircraft took off with known defects, let alone unknown ones, there would probably be far fewer people flying today, even given the presence of multiple redundancies and backup systems.

We could, of course, add more checks and procedures to try to prevent any mistakes from being made but, in my experience and opinion, too many checks and procedures can have the opposite effect - it can result in people concentrating too much on the 'paperwork' and not enough on actually doing the job right.

I'm also firmly of the belief that ill thought out policies or procedures can sometimes make things less safe rather than more so. For example, A320 engine cowling latch check signoff. It used to be a single signoff but that was changed to a dual signoff after some unlatched cowling incidents. Did that stop the unlatched cowling events from happening? No. Why? Let's just assume a scenario where some maintenance is running late and the mechanics (A + B) are under pressure to get the aircraft back out. Both A and B are supposed to check that the cowling is latched and sign it off. I can see that, under pressure, perhaps mechanic A might think 'B is going to check it so I'll just sign it off without actually looking', and mechanic B might think 'A has already checked it so I'll just sign it off without actually looking'. We're only human, after all. Do you think that either A or B would take that sort of risk if they didn't think someone else was also going to check it?

I don't have any figures to show whether or not the dual check on the A320 cowlings has made things better or worse but, over the years, I've seen many instances of additional checks and measures actually making things worse, not better.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-15 06:23:39 and read 15040 times.

You are of course correct BUT one thing that has be a great feature of the airline industry is a fanatical desire to understand each crash and why it happened. This to me, whilst not a crash, is a serious safety issue. I expect these are dedicated wiring runs. There are, as stated above, ways to ensure the correct circuit is connected to the right switch.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: oldeuropean
Posted 2013-08-15 06:25:50 and read 15070 times.

Here we come:

http://www.spiegel.de/wissenschaft/t...ken-falsch-verkabelt-a-916712.html

As anwer for some here, who want to downplay these findings:

Quote:
... Völlig anders sieht es aber beispielsweise beim Start aus, betont Fricke. Gerate in einer solchen Situation ein Triebwerk in Brand und das falsche werde stillgelegt, müsse die Besatzung notfalls mit dem brennenden Triebwerk weiterfliegen. "Wenn ich den Schub brauche, um zum Ausweichen von Hindernissen Höhe zu gewinnen, muss ich ihn holen, wo immer ich ihn herbekomme", erklärt Fricke. "Da hat man gar keine andere Wahl." In jedem Fall aber sei die Auslösung der falschen Löschanlage ein "Horrorszenario für Piloten".

... But at take off, it looks completely different, says Fricke. Especally in such a situation, if one engine is on fire, the false will shut down, the crew would have to fly further with the burning engine. "If I need to push to win height to hurdle obstacles, I have to take thrust wherever I can get it," said Fricke. "Since you have no other choice." In any case, the triggering of a false extinguishing system is a "nightmare scenario for pilots."


[Edited 2013-08-15 06:33:16]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: fcogafa
Posted 2013-08-15 06:32:00 and read 15023 times.

As it seems restricted to ANA, might it be their maintenance quality control issue, not Boeings?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbored
Posted 2013-08-15 07:45:22 and read 14914 times.

Quoting fcogafa (Reply 76):
As it seems restricted to ANA, might it be their maintenance quality control issue, not Boeings?

Could be, or could just be that they have earlier frames. Maybe they learnt how to build / test them more thoroughly after the first few.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-15 07:54:05 and read 14853 times.

One would have thought the test process for the fire extinguisher is substantially the same on a 737 as it is on a 787.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-15 08:06:51 and read 14809 times.

Quoting 7BOEING7 (Reply 65):
If the fire goes out after pulling the fire handle (most likely event) the fire bottle isn't even used.

All depends if the FIRE ENG message stays.

Quoting Boeing12345 (Reply 71):
Disconnect the squib and install a "test box" then activate the appropriate squib switch in the flight deck. The box would measure the amperage and ensure the correct bottle position.

Not too sure if this is the squib at this stage, or arming the squib. Could be the correct discharge is working, however the wrong one is armed. Could be the rotating the handle L/R is connected the same bottle instead of different bottles. I think there is 4 possible combinations on how they could have done this.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-15 08:15:18 and read 14794 times.

Quoting StTim (Reply 78):

One would have thought the test process for the fire extinguisher is substantially the same on a 737 as it is on a 787.

That did not stop having the issue to 737s etc many years ago as well

"Apr. 4, 1989 1:02 AM ET
SEATTLE (AP) _ Thirty-six more Boeing Co. jetliners have been found with crossed wiring or plumbing in fire-suppression systems, bringing the total number of Boeing planes with the problems to 95, the Federal Aviation Administration said Monday.
The 36 additions all belong to foreign carriers, KIRO-TV quoted the FAA as saying.
FAA spokesmen in Seattle were not immediately reachable by telephone Monday night to confirm the data.
As of March 10, the FAA had received reports of 59 Boeing planes with crossed wires, KIRO reported. The problems have been found over the last year.
The 36 planes either had crossed plumbing lines or crossed wiring in the fire emergency system, and most of the planes were built since 1981, KIRO reported.
The FAA early this year ordered inspections of about 740 Boeing 737s, 747s, 757s and 767s produced since 1981 to resolve concerns about crossed wiring. Most foreign aviation agencies ordered their carriers to make similar inspections.
Boeing earlier confirmed that the repeated wiring mishaps have prompted the company to start an engineering study in an effort to prevent crossed wires and pipes.
Two main miswiring problems can occur in the engine and cargo fire warning and suppression system and could interfere with the fire extinguishing system in planes, KIRO reported.
Of the 95 total discrepancies, 68 were wiring problems, the station reported. Of that number, 24 planes had wiring problems in the engine fire warning and suppression systems and 44 planes were found to have cargo fire warning and suppression systems wiring problems.
The other 27 discrepancies were plumbing problems, which were all on 767s."

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: asctty
Posted 2013-08-15 08:25:04 and read 14729 times.

Quoting fcogafa (Reply 76):
As it seems restricted to ANA, might it be their maintenance quality control issue, not Boeings?

Surely, given the limited amount of flying these 787s have had due to other problems, the requirement to be conducting maintenance which involved messing around with the WIRING of the fire suppression system is pretty low? It's more likely to be original sin from build??

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-16 00:23:37 and read 14106 times.

Seems United have found at least one aircraft with the same issue. Boeing has traced this back to a "improper assembly".

Posted 2013-08-16 06:47:32 and read 13602 times.

According to the Wall Street Journal, "Boeing Traces Improperly Assembled Engine-Fire Extinguishers to Supplier's Bottles".

Excerpts:

"Boeing Co. says it has traced the improperly assembled engine-fire extinguishers on 787 Dreamliners to the manufacturing of bottles at a supplier's facility."

"The plane maker said in a written statement that the improper assembly, which has been confirmed to have been found on three ANA jets in Japan, "does not present a safety of flight issue because the bottles are not the only means of fire extinguishing for engines and there are multiple redundancies within the fire extinguishing system."

"United Continental Holdings Inc., which operates seven 787s, found "at least one" jet with improperly assembled extinguishers, according to one person familiar with its inspections."

Supplier was not named in the article. IMHO, the second para above is a bit defensive and unnecessary. If one takes that statement literally in that this does not present a safety of flight issue (as other redundant systems can do the job), then why bother having them at all?

[Edited 2013-08-16 06:48:22]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Unflug
Posted 2013-08-16 06:55:41 and read 13486 times.

Quoting sankaps (Reply 83):
According to the Wall Street Journal, "Boeing Traces Improperly Assembled Engine-Fire Extinguishers to Supplier's Bottles".

Excerpts:

"Boeing Co. says it has traced the improperly assembled engine-fire extinguishers on 787 Dreamliners to the manufacturing of bottles at a supplier's facility."

"The plane maker said in a written statement that the improper assembly, which has been confirmed to have been found on three ANA jets in Japan, "does not present a safety of flight issue because the bottles are not the only means of fire extinguishing for engines and there are multiple redundancies within the fire extinguishing system."

Does this mean that there was no cross wiring?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-16 07:40:52 and read 13380 times.

Quoting sankaps (Reply 83):
If one takes that statement literally in that this does not present a safety of flight issue (as other redundant systems can do the job), then why bother having them at all?

Perhaps they (also) serve as a redundancy for the other systems should one of them fail?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-16 09:02:15 and read 13246 times.

It seems we're making assumptions based on vague data.. and assigning blame based on those assumptions..

Do we know exactly where the error is?, do we know if this is part of a supplier buildup and which supplier? Was it the engine build up, the strut buildup or the installation buildup? Do we even know if the 4 reported cases are identical?

In reading the Boeing release, it would appear that the error(s) occurred in a supplier assembly that is not subject to detailed re-inspection prior to FAL installation. So we now may have 2 different occurrences of vendor QA lapses (ELT and this). From years in the factory, vendor lapses are not uncommon.. repeated lapses by the same vendors are uncommon, however when they do occur vendors get terminated or bought out by someone who will ensure quality.

Previous models the engines went to the Boeing Propulsion Systems for buildup and that would have been where the error happened, I believe that work has been subcontracted out on this plane.

As noted above Boeing designs in redundancy.. primarily one case one path is damaged or has been utilized without the desired effect.. the only one they don't have is a squib to blow the engine fuse pins and drop the engine..       pun intended

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: par13del
Posted 2013-08-16 10:48:52 and read 13045 times.

Quoting sankaps (Reply 83):
If one takes that statement literally in that this does not present a safety of flight issue (as other redundant systems can do the job), then why bother having them at all?

Redundancy.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-16 12:57:35 and read 12856 times.

Quoting Stitch (Reply 85):
Perhaps they (also) serve as a redundancy for the other systems should one of them fail?

Sure, I understand the concept of redundancy completely but incorrect wiring of a redundancy system cannot be brushed off as "not a safety issue" unless it is equally safe for the aircraft to be flying with one of the redundant systems inoperative.

Additionally, if an actual engine fire were to occur and the wrong fire bottle fired, wouldn't that create confusion, waste time, and increase risk (and thereby directly have a safety implication)?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: wingman
Posted 2013-08-16 15:53:10 and read 12646 times.

Maybe Boeing is lying and United Tech is too. There is a likely a tightly scripted conspiracy unfolding that involves these two companies, their customers, and the FAA and NTSB. Surely this will all be exposed by morning and we can embark on yet another 787 bash fest. Just sit tight people, it won't be long now.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: moose135
Posted 2013-08-16 19:20:03 and read 12490 times.

An update on the story, from Yahoo Finance:

Quote:
Boeing Co. said Friday that a defect in engine fire extinguishers for its new 787 jets occurred during manufacturing of the bottles at a supplier's facility and the issue was being fixed. Boeing has told airlines to inspect the extinguishers and given them directions for fixing improperly configured fire-suppression systems.

The company identified the supplier as Kidde, a division of United Technologies Corp.

United Technologies spokesman Daniel Coulom said that an assembly error affected "a limited number" of fire extinguisher bottles. "The error has been corrected, and we are working with Boeing and the airlines to complete the necessary inspections, which we expect will be completed over the next few days," he said.

Full story:
http://finance.yahoo.com/news/boeing...extinguisher-defect-210513959.html

Also from the story, the official statement from UA:

Quote:
United spokeswoman Christen David said Friday that the airline had completed five of seven inspections and found no problems.


[Edited 2013-08-16 19:23:04]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-16 23:38:22 and read 12261 times.

Quoting moose135 (Reply 90):

The yahoo article directly contradicts the WSJ, the WSJ said at least one was found at UA.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-16 23:56:51 and read 12217 times.

Quoting moose135 (Reply 90):
The yahoo article directly contradicts the WSJ, the WSJ said at least one was found at UA.

Well they evidently have two left to inspect, so perhaps it is one of those two.

Or Jon was mistaken.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: asctty
Posted 2013-08-17 03:17:12 and read 11979 times.

Even if this was a supplier installation issue, Boeing's pre-delivery QA systems should have picked it up!

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: wjcandee
Posted 2013-08-17 03:18:12 and read 12009 times.

Quoting zeke (Reply 91):
The yahoo article directly contradicts the WSJ, the WSJ said at least one was found at UA.

Looking online at the Asia WSJ and US WSJ versions of this article, Jon is no longer saying that UAL has found a problem. The Asia version says they say they found nothing, and the US version says they are continuing their inspections.

Jon's a good guy, but he gets info from unofficial sources sometimes, and clearly the official source contradicted his inside info. It's that transition phase from blogger to real journalist writing real articles for the real paper not the blog.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-17 03:48:29 and read 11980 times.

Quoting asctty (Reply 93):
Even if this was a supplier installation issue, Boeing's pre-delivery QA systems should have picked it up!
Quoting kanban (Reply 86):
In reading the Boeing release, it would appear that the error(s) occurred in a supplier assembly that is not subject to detailed re-inspection prior to FAL installation.

Based on Boeing's comments to the WSJ(?), it sounds like this is an item that may not be QA'd once it leaves the supplier (so the supplier is responsible for QA).

[Edited 2013-08-17 04:31:40]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: trex8
Posted 2013-08-17 04:08:36 and read 11912 times.

Quoting asctty (Reply 93):
Even if this was a supplier installation issue, Boeing's pre-delivery QA systems should have picked it up!

OEMs 'reinspecting" supplier components is not without problems. Pratt reassembled a subassembly wrongly after a QA inspection of a new supplier and an F16 crashed as a result!

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-17 04:28:00 and read 11896 times.

Quoting Stitch (Reply 95):

Are you able to post their press release, as I see nothing on http://boeing.mediaroom.com/

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-17 04:33:53 and read 11883 times.

Quoting zeke (Reply 97):
Are you able to post their press release, as I see nothing on http://boeing.mediaroom.com/

I was going off kanban's comments about "Boeing's release" in Reply 86, which I interpreted to mean a press release statement. However, kanban might be referring to their statement reported in the WSJ originally quoted by sankaps in Reply 83.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: flyglobal
Posted 2013-08-17 05:02:23 and read 11817 times.

Quoting mats01776 (Reply 44):
In a modern vehicle design many of the non-emergency, non-critical signals are carried on multiplexed "buses" similar to Ethernet rather than point-to-point wiring.

I am surprized that error prevetion is obviously not part of the design process.

In car industrie case such things are done by physically different male female which will only fit in the the connection they are designed for, nut to mention even color coding and such other things. So we deisgn vehicles to be menufactured for differently skilled staff arund the globe.
We engineers hate our manufacturing teams sometiimes when they 'bother' us with their error prevention requests, bbecause it causes engineering to release more parts and releases as well as it costs more money.

At the end its a balance between all needs.

However I always assumed that the airline industrie is way ahead of vehicle industrie in that matter.
Surprized

Greetings

Flyglobal

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Mats01776
Posted 2013-08-17 05:36:19 and read 11725 times.

Quoting flyglobal (Reply 99):
I am surprized that error prevetion is obviously not part of the design process.

I agree 100%.

Furthermore, I am even more bothered by the fact that this subsystem defect was not caught in either the subsystem Q/A process after manufacturing or during the systems integration testing process.

This makes me wonder how comprehensive the systems integration testing process is.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: asctty
Posted 2013-08-17 05:50:50 and read 11703 times.

Quoting Stitch (Reply 95):
Quoting asctty (Reply 93):
Even if this was a supplier installation issue, Boeing's pre-delivery QA systems should have picked it up!
Quoting kanban (Reply 86):
In reading the Boeing release, it would appear that the error(s) occurred in a supplier assembly that is not subject to detailed re-inspection prior to FAL installation.

Based on Boeing's comments to the WSJ(?), it sounds like this is an item that may not be QA'd once it leaves the supplier (so the supplier is responsible for QA).


I am a system safety engineer as it happens. In my world the 'platform' designer is responsible for presenting the safety case to the operator and the industry regulator. Therefore any supplier safety statements must be assessed before the platform is delivered. Normally this includes a rigorous QA process of suppliers equipment. It's not as if the fire extinguishing system is an after-market add-on the airline has installed on the B787 is it?

If this level of rigour isn't the case in the airline industry then I am really concerned.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-17 07:36:35 and read 11680 times.

Quoting Stitch (Reply 98):
I was going off kanban's comments about "Boeing's release" in Reply 86,

I was going off the news release that quoted Boeing, not a separate Boeing release.. sorry for the confusion..

Quoting trex8 (Reply 96):
OEMs 'reinspecting" supplier components is not without problems.

Of all the processes of traditional manufacturing, reinspecting components of supplier assembled assemblies is the most costly and least productive operation imaginable. This why supplier assemblies only receive a "shipping damage" assessment and the necessary functional tests/checks following installation. This is also true in other industries. For those not aware of it, because the old receiving inspection was a major cost and delay point, with little to no results, Boeing did away with it and relies on documented source inspection. There maybe some "should" beliefs out there, however statistically it's been proven to be the correct decision. (On a similar note, does Ford reinspect all components from suppliers before installation, or do they rely on supplier inspection?)

It sounds like the engine build ups come straight from UTX to the installation point.. are installed by mechanics who are looking at only one end of a wire harness. Then in a couple days it's out to the sunlight (or rain)..

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: asctty
Posted 2013-08-17 07:50:00 and read 11636 times.

Quoting kanban (Reply 102):
Of all the processes of traditional manufacturing, reinspecting components of supplier assembled assemblies is the most costly and least productive operation imaginable. This why supplier assemblies only receive a "shipping damage" assessment and the necessary functional tests/checks following installation. This is also true in other industries. For those not aware of it, because the old receiving inspection was a major cost and delay point, with little to no results, Boeing did away with it and relies on documented source inspection. There maybe some "should" beliefs out there, however statistically it's been proven to be the correct decision. (On a similar note, does Ford reinspect all components from suppliers before installation, or do they rely on supplier inspection?)

It sounds like the engine build ups come straight from UTX to the installation point.. are installed by mechanics who are looking at only one end of a wire harness. Then in a couple days it's out to the sunlight (or rain)..

It doesn't matter, the supplier of the end product to the customer is responsible for it's safety!

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-17 07:54:26 and read 11638 times.

I am wondering what wiring issue there could be in the assembly of the bottle.

All I can assume is that the bottles are configured to be left or right and this was incorrect.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-17 09:25:45 and read 11529 times.

Quoting asctty (Reply 103):
It doesn't matter, the supplier of the end product to the customer is responsible for it's safety!

this reminds me of the QA guy who insisted on 100% destruct test on every engine bottle pin coming in. Net result no sub standard parts found, but hanging engines was delayed for two weeks. In an armchair 100% redundant inspection sounds good, in a business it's suicide.

One could carry your thought out and double the cost of a plane.. with no benefit to supplier or customer. What Boeing did do was locate and identify the problem (better than A.net), contact the supplier who admitted the error and initiated discovery and corrective action ... probably on their tab.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: asctty
Posted 2013-08-17 12:36:52 and read 11253 times.

Quoting kanban (Reply 105):
this reminds me of the QA guy who insisted on 100% destruct test on every engine bottle pin coming in. Net result no sub standard parts found, but hanging engines was delayed for two weeks. In an armchair 100% redundant inspection sounds good, in a business it's suicide.


Sorry, but I disagree when we are talking about safety critical systems.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: rheinwaldner
Posted 2013-08-18 23:54:00 and read 10672 times.

Quoting Stitch (Reply 85):
Perhaps they (also) serve as a redundancy for the other systems should one of them fail?

Exactly, which means that the security of the whole package was affected. Those other systems no longer are failsafe.

Loss of redundancy is loss of safety. It is that simple.

How big of fools does Boeing take us?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-19 00:37:10 and read 10594 times.

Quoting Mats01776 (Reply 100):
Furthermore, I am even more bothered by the fact that this subsystem defect was not caught in either the subsystem Q/A process after manufacturing or during the systems integration testing process.

I am not sure if it related, I think the FAA fined Boeing not that long back (May/2013 ?) to breakdowns in the QA process.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-19 09:06:10 and read 10148 times.

Quoting rheinwaldner (Reply 107):
Loss of redundancy is loss of safety. It is that simple.

if that were the case, why bother with double or triple redundant systems?.. All life has risks, double and triple redundancies may reduce a failure mode from a tenth of a percent to a thousandth of a percent or better.. but no amount will remove it entirely except not flying.
Some of these anal 'should have' inspected statements remind me of another inspector you would have loved.. since life rafts are totally tested by the manufacturer and to deploy one means sending it back to the manufacturer for repacking, this guy decided he needed to do a spot inspection to ensure it would inflate because his mother was going to be flying to Europe, they had to attack it with knife to deflate it quickly and save the idiot who was trapped underneath, thereby destroying the raft. In this case from your armchair, you would fire the squibs and then have to sent the engine back to the shop for cleaning, refitting and retest.. how many times per engine would you do that realizing the each time you had to install new parts that would have to be destruct tested to pass? yet you buy a new car and assume that every component was tested and inspected after installation (which they weren't) and zip right out on the autobahn to see how fast it will go assuming the brakes and wheels won't fail and assume somebody remembered to put fluid in the transmission?..

Quoting zeke (Reply 108):
I am not sure if it related, I think the FAA fined Boeing not that long back (May/2013 ?) to breakdowns in the QA process.

I have no problem with the comment if you have documentation as to relevancy to this threads subject .. otherwise it smacks of trolling.. Remember that this error was inside a supplier delivered assembly and the tests are simple continuity checks to ensure the connectors are seated correctly.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-19 09:14:16 and read 10113 times.

Quoting kanban (Reply 109):
if that were the case, why bother with double or triple redundant systems?.. All life has risks, double and triple redundancies may reduce a failure mode from a tenth of a percent to a thousandth of a percent or better.. but no amount will remove it entirely except not flying.

But surely it is clear that reduction from triple to double or double to single redundancy reduces the "safety net" and therefore it is disingenuous to suggest that loss of a redundancy has "no safety impact"?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: scbriml
Posted 2013-08-19 09:20:15 and read 10090 times.

Quoting sankaps (Reply 110):
But surely it is clear that reduction from triple to double or double to single redundancy reduces the "safety net" and therefore it is disingenuous to suggest that loss of a redundancy has "no safety impact"?

Indeed, if loss of redundancy has "no safety impact" one would have to ask why the redundancy is there in the first place!   

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-19 09:30:25 and read 10049 times.

Quoting sankaps (Reply 110):
But surely it is clear that reduction from triple to double or double to single redundancy reduces the "safety net" and therefore it is disingenuous to suggest that loss of a redundancy has "no safety impact"?

the redundancy allows one to safely land .. it is not the intent to fly with half or a third of a redundant system inoperable as standard practice. Although there are cases for some models where brakes, thrust reversers , and several other systems may be locked out.. you can fly with the redundancy reduced... Is it safe? yes. Is it as safe as when all are on line? no, but the increased risk is too small to warrant losing sleep over.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-19 13:10:47 and read 9825 times.

Quoting kanban (Reply 112):
Is it safe? yes. Is it as safe as when all are on line? no, but the increased risk is too small to warrant losing sleep over.

Even in this specific case where the bottles are cross-wired? So if the left engine is on fire, the right engine bottles get deployed? The risks this poses (exacerbated by the confusion and loss of time) is surely not something that can be dismissed as inconsequential?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airtechy
Posted 2013-08-19 13:21:19 and read 9793 times.

Quoting sankaps (Reply 113):
So if the left engine is on fire, the right engine bottles get deployed?

It is not clear that the swap was left to right....I have not seen that confirmed. It could have been a swap within the same engine.

AT

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Speedbored
Posted 2013-08-19 13:36:10 and read 9773 times.

Quoting airtechy (Reply 114):
It is not clear that the swap was left to right....I have not seen that confirmed. It could have been a swap within the same engine.

Fightglobal were certainly stating that it was a left-right swap:
"In the event the flightcrew needed to extinguish a fire in one engine, the crossed wires would have caused the extinguisher in the other engine to be activated."
http://www.flightglobal.com/news/articles/ana-finds-engine-fire-extinguisher-wiring-issue-on-three-787s-389470/
No indication of their source, though.

And would JAL really have turned a flight round if the switch had only been between bottles within the same engine?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airtechy
Posted 2013-08-19 13:55:07 and read 9718 times.

Quoting Speedbored (Reply 115):

And would JAL really have turned a flight round if the switch had only been between bottles within the same engine?

JAL...and other operators...seem to be ultra conservative in their handling of failures on the 788. At the time of the flight turn, who knows what information they had about the failure so I assume they acted cautiously.

You would have thought this error would have resulted in an AD. One has to assume it was handled via a service bulletin. Sill no source from Boeing or the FAA about the exact error.....that I've seen.

AT

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-19 14:32:43 and read 9627 times.

Quoting airtechy (Reply 116):
You would have thought this error would have resulted in an AD. One has to assume it was handled via a service bulletin. Sill no source from Boeing or the FAA about the exact error.

It may only warrant a service letter from the supplier installer. Not everything needs an AD.. Nor do they need FAA publication.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: rheinwaldner
Posted 2013-08-19 21:05:34 and read 9420 times.

Quoting kanban (Reply 109):
Quoting rheinwaldner (Reply 107):Loss of redundancy is loss of safety. It is that simple.

if that were the case, why bother with double or triple redundant systems?..

I don't know why we have to discuss whether safety is impacted by the number of available redundant systems or not. Questioning that point primarily reveals a serious lack of understanding about safety.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: TheRedBaron
Posted 2013-08-19 21:47:37 and read 9347 times.

Quoting frigatebird (Reply 70):
Which I hope won't have the snags of -8...

well the 789 was supposed to be roled out in July, and I saw it quite unfinished at the Boeing Factory last week.... does anybody know how the program is delayed, or Boeing does not bother to inform about delays?

I find it disturbing the amount of little problems that could be catastrophic in this aircraft, if these continue even Harper´s Bazaar will make articles on the 787.

On ething I really find hilarious was buying the official 787 book at Boeing museum of flight at Renton, and the book ends with no first flight, no EIS, not even mentioning of final system integration.... hell I think they had a deadline from the publisher and the darn 787 was delayed so much that they published and unfinished book.. unbelievable !!!

I really hope they get it right on the 9 and they are doing the more recent aircraft better....

TRB

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-19 22:00:45 and read 9322 times.

Quoting TheRedBaron (Reply 119):
well the 789 was supposed to be roled out in July, and I saw it quite unfinished at the Boeing Factory last week.... does anybody know how the program is delayed, or Boeing does not bother to inform about delays?


What you saw were the second and third 787-9s.

The first 787-9, ZB001, was completed and painted at the end of July and is currently being prepared to start certification and flight testing.

[Edited 2013-08-19 22:04:08]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: jetmech
Posted 2013-08-19 23:49:05 and read 9187 times.

Quoting airtechy (Reply 114):
It could have been a swap within the same engine.

This may have been possible with RR powered 744's (and classic?), as they had a pair of fire bottles in the nose cowl of each engine. IIRC, the GE and P&W 744's had a pair of engine fire bottles mounted in the inner leading edge of each wing, these being shared by both the engines on that wing.

I wonder what the fire bottle setup is like on the 787? If it is similar to the 777 setup, which consists of a pair of bottles shared by both engines (whatever the type), it may not be possible to "swap" within a single engine   .

Regards, JetMech

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-20 01:43:55 and read 9087 times.

Quoting kanban (Reply 109):

I have no problem with the comment if you have documentation as to relevancy to this threads subject .. otherwise it smacks of trolling.. Remember that this error was inside a supplier delivered assembly and the tests are simple continuity checks to ensure the connectors are seated correctly.

As I stated previously, I am not sure if they are connected. All I know is the FAA (not me) stated they were going to undertake a comprehensive review of the 787 earlier this year, and Boeing were subsequently fined by the FAA (not me) for QA issues. Now if these are not the same Boeing company as the one that assembles the 787, I stand corrected. One would assume these are procedural issues.

I do not have detailed knowledge of what the issue is on these bottles, I do know if these bottles were installed during maintenance the operator would have needed the equivilant to a 8130, and also be legally responsible to determine if they are airworthy. If your comments on this thread are to be believed, you are suggesting Boeing is blindly installing components on aircraft without any form of scrutiny, it seems to me one of the potential checks and balances are not being used.

Just for our clarification on your "trolling" comment, have you had a long standing relationship with Boeing in the past ?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Unflug
Posted 2013-08-20 02:04:54 and read 9048 times.

Quoting zeke (Reply 108):
I am not sure if it related, I think the FAA fined Boeing not that long back (May/2013 ?) to breakdowns in the QA process.
Quoting kanban (Reply 109):
I have no problem with the comment if you have documentation as to relevancy to this threads subject
http://www.faa.gov/news/press_releases/news_story.cfm?newsid=14954

Nonconforming fasteners on 777 aircraft are not directly related to this thread, but since most of this thread is about possible QA issue...

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: TheRedBaron
Posted 2013-08-20 04:56:33 and read 8891 times.

Quoting Stitch (Reply 120):
What you saw were the second and third 787-9s.

The first 787-9, ZB001, was completed and painted at the end of July and is currently being prepared to start certification and flight testing.

Thanks! I did not know that I stand corrected.

BTW I did not see the finished AC outside, then again KPAE is full of Aircraft in various stages of manufacturing .

TRB

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: KarelXWB
Posted 2013-08-20 05:18:25 and read 8837 times.

Quoting Stitch (Reply 120):
The first 787-9, ZB001, was completed and painted at the end of July and is currently being prepared to start certification and flight testing.

Not sure if I agree with the term "completed" because the flight test equipment was installed after the paint job.

Quoting TheRedBaron (Reply 124):
BTW I did not see the finished AC outside, then again KPAE is full of Aircraft in various stages of manufacturing .

It is still inside the assembly building for flight test equipment installation and should roll out to the flightline later this month.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-20 08:45:44 and read 8690 times.

Quoting zeke (Reply 122):
have you had a long standing relationship with Boeing in the past ?

Zeke, the answer is off topic however I'll respond.. yes I worked 35 years there, most on the factory floor in production control, manufacturing engineering, purchasing and process audit. I was iinvolved in the conversion to lean manufacturing.

Quoting zeke (Reply 122):
you are suggesting Boeing is blindly installing components on aircraft without any form of scrutiny, it seems to me one of the potential checks and balances are not being used.

Back on track.. Boeing does not "blindly" install components, however they have removed the redundant receiving inspection and moved the quality certification back to the suppliers much the same was the auto and other industries have. Take for instance the 41 section, it arrives from Spirit fully stuffed (wiring, insulation, electronics, linings, wheel and column, control stands) .. to perform an old style duplicate receiving inspection, these would have to be removed and reinstalled. The process today forces the QA (with documentation) back to the manufacturer, when the units are installed, systems checks are performed to ensure the systems work, then when Everett assembles the sections, the systems are connected to the adjoining sections and again the connections are tested...

In the engine scenario, UTX builds up the engine to the installation level, tests their installation work and delivers it to the factory the night before load. It's then installed and the interfaces tested.

Same with landing gear, Boeing no longer builds them up (electrical, hydraulic, wheels, tires & brakes) but receives them from a supplier the night before installation.

Looking back on the old method, it seldom caught problems, increased the inventory Boeing had on hand, and when a problem was found, it meant finding all the pieces in the stores, subassembly, supply line and sending them out for rework/repair. that took months. Today, if problem is identified, it is checked and fixed on the next delivered unit. Much faster response. Under the old system, suppliers might ship 100 a/ps worth of stock at a time.. the volume caused receiving inspection to do sample inspection which might miss a error.. plus we found that the suppliers relied on Boeing to do their detailed inspection.. now suppliers must do their own and document it.. or lose the contract.

Note these processes are not unique to 787, they have been in place for the years for the other models ( the shift started 15 years ago... ) and have been verified and validated by the FAA during the ACSEP audits.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-20 11:21:46 and read 8612 times.

Quoting scbriml (Reply 111):
if loss of redundancy has "no safety impact" one would have to ask why the redundancy is there in the first place!

Increase the Operational Reliability.
A system could very well be certified as "safe", but if its availability is low (ie Mean Time Before Failure is low and Mean Time To Repair is high, in relative terms), it could seriously impact the operational capability of an aircraft by fairly often creating big delays for repairs. You can improve that with redundant elements used as back up, at the price of increasing the total system weight. In the end it's a balance between hauling a little more weight versus schedule disruption.
If all systems were necessary for safe dispatch, there wouldn't be a MEL (or it would only cover IFE, galleys and toilets)

http://en.wikipedia.org/wiki/Reliability_engineering
http://en.wikipedia.org/wiki/Availability_%28system%29



Quote:
I do not have detailed knowledge of what the issue is on these bottles

That's what bothers me with this whole thread. Stich asked in reply 40 if anyone had any idea of how the system works. Over 5 days and 85 replies later, there is still no hint as to :
- what the extinguisher system archicture is : where are the bottles ? fueselage ? wings ? pylons ? common to both engines or seperate ?
- how does it work ?
- how is it wired ? by direct ON/OFF discrete signals ? via a dedicated bus like a ARINC429 ? or via the main data network including AFDX and RDCs and probably other types of networks ? Or a combination of the above (which I suspect) ?
- is it the only contributing system to the "engine fire supression" function ? What is its exact role within the scenario "engine fire", compared to that of other systems ? What actions would be taken before using the extinguisher, and after using it ? And no it is not necessarily obvious...there is no simple relation 1 system=1 function anymore, everything is interrelated. Which is a main reason for all the difficulties on the last 2 major airliner programs.

Actually, does anyone have any beginning of a start of an idea of a clue as to what happened, apart from 3 vague and somewhat contradictory reports in the WSJ, Flight Global and Yahoo ? Or is this a free for all 787 bashing thread based on just about nothing ?

If we're going to bash Boeing, let's at least do it properly ! Lord knows there are enough documented 787 issues to do so...I don't really understand the need to invent a new one.
Yes there was a QA screw-up. Yes it should have been caught during the assembly process (whether in FAL or before is not important, as there should be QA procedures established by suppliers and agreed to by the OEM). But these things happen, and will happen again, as long as company A, B or C will be staffed by humans. And in this case the issue was caught and corrected, and there is no reason to believe the root cause is not being looked into. Only circumstantial evidence regarding something that happened over 3 years ago on another program. So maybe we should just get over it ?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: czbbflier
Posted 2013-08-20 11:30:00 and read 8593 times.

Quoting kanban (Reply 109):
Some of these anal 'should have' inspected statements remind me of another inspector you would have loved..

lol. Guilty as charged. Yes, this is a great example of the inspection process gone waaaay too far... and gone terribly wrong.

Quoting kanban (Reply 126):
Note these processes are not unique to 787, they have been in place for the years for the other models ( the shift started 15 years ago... ) and have been verified and validated by the FAA during the ACSEP audits.

Thank you for your insight. Very informative.

One question though- Do you think there have been QA deficiencies from 787 suppliers from the get-go? "Fasteners", wing box, delamination, batteries, and now extinguisher wiring?

This seems like an awfully long list, even for a new designed aircraft. Or is much of this down to the basic engineering and working with new materials?

Cheers

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-20 11:59:42 and read 8528 times.

Without knowing the systems architecture (as airmagnac correctly points out no one has made any substantive statement) I cannot believe that the bottles and cockpit all came pre stuffed on a single sub assembly. As such one would expect some sort of integration test after hook up.

A final point is that you would also expect Boeing to have QA teams that are at or visit key suppliers to ensure their systems and processes are adhered to. It can never be 100% - there is no such thing. There are however all the benefits he so clearly documents.

Like car manufacturers frame makers are becoming much more assemblers than manufacturers. This will continue.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-20 12:02:30 and read 8531 times.

Quoting airmagnac (Reply 127):
If all systems were necessary for safe dispatch, there wouldn't be a MEL (or it would only cover IFE, galleys and toilets)

Let's stick to the specific issue on hand. Can inoperative or miswired engine fire bottles be MEL'd on a revenue passenger flight? Is there no safety risk if the wrong engine's bottles are fired if an engine is on fire?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-20 12:40:36 and read 8454 times.

Quoting sankaps (Reply 130):
Let's stick to the specific issue on hand. Can inoperative or miswired engine fire bottles be MEL'd on a revenue passenger flight? Is there no safety risk if the wrong engine's bottles are fired if an engine is on fire?

The redundancy/MEL stuff was an answer to a specific question about redundancy, slightly off topic.
But as for the possibility of MELing the fire bottles, I just do not know. Here's a 777 fire extiguishing system description from the 777 FCOM :



For all I know (ie, nothing) the 787 could be an improvement on this design, with a more flexible functional architecture and a better understanding of the various failure probabilities allowing a design with 2 bottles, each one being enough to cover a fire scenario and one serving as primary, the other as operational back-up. Maybe. Why not ?

But whatever...my point is that we can invent anything we want regarding this issue and its potential consequences, because so far I have not seen any hard data. I have not seen any confirmed statement that the bottles are dedicated to a specific engine, I have not seen any confirmed evidence of how the bottles are wired into the data network(s), I have not seen any 787 engine fire procedure, I have not seen any fire detection & suppression system description. I have not seen anything at all apart from "there was a wiring error".
It could be just me, but I suspect no one here really knows more than I do. So just to be sure, I'll repeat my question : is there anyone who has any shred of confirmed data regarding this problem ?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-20 12:53:51 and read 8419 times.

Quoting sankaps (Reply 130):
Can inoperative or miswired engine fire bottles be MEL'd on a revenue passenger flight?

Looking through Section 26: Fire Protection, I cannot find anything specifically relating to the main engine fire suppression system so I am guessing the entire system is required to be operational for dispatch.

There is System & Sequence number 26-21-01 with an item title of "Fire BTL DISCH Lights (Engine, APU, Cargo)" that shows4 installed, but none are required for dispatch.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: rcair1
Posted 2013-08-20 12:54:17 and read 8428 times.

Quoting rheinwaldner (Reply 107):
How big of fools does Boeing take us?

About as big a fool as some accuse Boeing of being.

Quoting kanban (Reply 126):
Back on track.. Boeing does not "blindly" install components, however they have removed the redundant receiving inspection and moved the quality certification back to the suppliers much the

Thanks for the very informative post. BTW - this is very consistent with changes in manf I've been involved in for 30+ years.
The last thing you want, from an efficiency/cost standpoint is to duplicate component testing at arrival. It is inefficient and not particularly effective. Integration testing - yes.

-bob

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: 7BOEING7
Posted 2013-08-20 12:57:57 and read 8436 times.

Quoting airmagnac (Reply 131):
The redundancy/MEL stuff was an answer to a specific question about redundancy, slightly off topic.
But as for the possibility of MELing the fire bottles, I just do not know. Here's a 777 fire extiguishing system description from the 777 FCOM :


Per the 787 MEL the fire bottles are not "listed" therefore can't be MEL'd. The diagram for the 787 is the same as you displayed for the 777 and the general operation is the same -- with an engine fire indication the fire handle is pulled, if the fire is not out the fire handle is rotated left or right to discharge the #1 or #2 bottle respectively, if after 30 seconds the fire is not out the fire handle is rotated the opposite direction to discharge the other bottle -- doesn't matter which bottle you discharge first.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-20 13:37:53 and read 8358 times.

Quoting czbbflier (Reply 128):
One question though- Do you think there have been QA deficiencies from 787 suppliers from the get-go? "Fasteners", wing box, delamination, batteries, and now extinguisher wiring?

First one needs to separate design deficiencies from quality deficiencies.
* Wing box, batteries, were design deficiencies.. yes they are seen as quality issues, but QA does not validate the engineering, they ensure the product is built and tested per the engineering even if wrong.
* Fasteners were a parts supply deficiency and a production stop gap.. all were accounted for, and removed. There is a process for that accountability.
* Rework of the titanium fasteners was a Manufacturing Plan error.. the mechanics did the work as instructed, it was audited to the job paper. Yes the plans are reviewed by QA who didn't catch the missing deburr and clean operation. Howeve,r if the FAA or a process auditor had been watching and the mechanic did deburr and clean without it being on the job paper, it would have been a finding. There is a process for a mechanic who spots a job error like that to get it immediately corrected through liaison ME in conjunction with QA.
* Delamination may be a QA issue or it may be a production/layup issue.. it is difficult to spot during layup and sometimes only actual use brings it to a point of recognition. the end result is a quality issue.
* the aileron fillers was a QA issue
* the wiring and the ELT pinching are vendor QA issues
* the FOD in the electrical panel was a manufacturing mistake, although there is no QA operation to check inside after rework in the compartment. Yes it is a quality issue but not a QA issue

There is a fine distinction between what is a quality issue and what can be inspected out by a Quality Control person. Also note QA personnel are not mechanics and inspect many types of operations..however they can only inspect to what is requested on the plan. If the plan says inspect aero dynamic smoothness after micro shaving, that's what they inspect.. they do not verify that the fastener hole was drilled in the correct location, then counter sunk, debarred, cleaned, primered. Now there may have been another inspection operation that verified those operations or they may be listed as a mechanic self inspection.

Quoting StTim (Reply 129):
A final point is that you would also expect Boeing to have QA teams that are at or visit key suppliers to ensure their systems and processes are adhered to.

There are QA teams under the purchasing division that routinely audit the suppliers, the FAA also audits the suppliers. Do they do parts inspections.. no. They look at the processes, statistical records, and quality processes. If a supplier has a problem (ailerons) they dispatch a team to identify with the supplier where the problem is and how to prevent it in the future. Many of these quality issues are mechanics not used to following the manufacturing plan to the letter, others are due to failing to re-certify tools, or using only current drawings. Sometimes it's using a chemical that is past the expiration date/time. (some sealants have a 3-4 hour window for use and then must be discarded, or if the operation is incomplete, stripped and the process started over... that is generally a result of poor planning and scheduling of the work).

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-20 13:55:31 and read 8316 times.

Many years ago I worked as a third party inspector on power stations during build. We did less process checks back then although there were coming in. We witnessed key tests and reviewed paperwork.

I do remember monitoring a key build stage of a turbine set where the manufacturer was not adhering to their procedure - they were welding at a current above that stated tolerance. Failed test, much egg on face and a few more guarantees.

My experience may not be aerospace and not very up to date but I do have a little background.

Must admit I did not expect extinguisher bottles to be centrally located. If for instance you have a Quantas 380 incident that cuts the pipework leading from the bottle to the engine?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-20 14:12:20 and read 8292 times.

Quoting 7BOEING7 (Reply 134):

That's more like it, thanks !  

Now from what I've seen on the net, the arrows between the fire handles in the cockpit and the bottles actually go through the Common Computing System, then probably via AFDX bus to an RDC near the bottles. All this uses soft-coded addresses, so is mostly independant of the physical layer, meaning a wiring switch would have little consequence.
On the last leg between the RDC and the bottles, if it is again via some sort of bus it would be soft coded and a switch is no big deal ; otherwise it could be a discrete signal, but if the discretes were switched the consequences are unclear.
If the whole system is symetric and there are sensors that detect which bottle has discharged first, then a switch is transparent.
If the controller does not get any feedback, but instead works on the hypothesis that the discharged bottle is indeed the one it commanded to discharge, again no problem because the switch would work twice and cancel itself out.

There could also be two seperate signals travelling through the networks along two seperate paths, and the bottle needs to receive two coherent "discharge" commands in order to work. In this case, a switch of one of the discrete lines between the 2 bottles would prevent the signals from ever being coherent. That would be a problem.

So it seems to me that
1) without functional connection diagrams, wiring diagrams and the name of the lines that have been switched, we'll never get to the bottom of this, or even close to the bottom
2) it could indeed be a very serious problem, but it just as well could be minor or even not a problem at all. Depending on the network architecture and system architecture

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-20 14:37:22 and read 8236 times.

Quoting StTim (Reply 136):
If for instance you have a Quantas 380 incident that cuts the pipework leading from the bottle to the engine?

Under FAR/CS 25.1309, the OEM would have to prove that his system can survive such an event.
The usual accepted mean of compliance for the Uncontained Engine Rotor Failure scenario is to perform a Particular Risk Analysis, which means creating a model of the event and using it to identify the zones of the aircraft which are exposed to debris.
From there the system must either be designed outside of these zones completely, or if it must pass through, then it must do so over several paths that cannot be hit during a same event.
That's the general idea, at least.

In this case, I'd guess there is a pipe along the forward spar and one on the back spar. Or maybe a need for fire extinguishing is considered incompatible with a UERF event, so no need for any particular precaution.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-20 14:59:17 and read 8208 times.

Looking at the illustration and a similar one of the 787, I must retract my comments about them being installed on the engine as it arrived from build-up.. it appears that the bottles are in the wheel wells. makes sense. The fact that UTX did the work through me off.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: StTim
Posted 2013-08-20 15:18:13 and read 8148 times.

Agree - not impossible to design around but at some point the cost of pipework, fixings, extra bottle capacity (there will be some loss in the pipework) will negate the simplicity of design and extra weight of bottles at the engone.

None of this is a hard and fast right answer. These are all design compromises that the engineers have to make day in day out.

Many years since I last got my hand dirty and I now push around ones and zeros. I do miss engineering.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: hivue
Posted 2013-08-20 15:20:54 and read 8158 times.

Quoting airmagnac (Reply 137):
Now from what I've seen on the net, the arrows between the fire handles in the cockpit and the bottles actually go through the Common Computing System, then probably via AFDX bus to an RDC near the bottles.
Quoting airmagnac (Reply 137):
without functional connection diagrams, wiring diagrams and the name of the lines that have been switched, we'll never get to the bottom of this, or even close to the bottom

What am I missing here? I believe the reports are saying the problem is in the extinguisher assemblies themselves. I would think that crossed wires in the bottles would be adequate explain the problem.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: PlanesNTrains
Posted 2013-08-20 20:18:19 and read 7985 times.

Quoting StTim (Reply 129):
Without knowing the systems architecture (as airmagnac correctly points out no one has made any substantive statement) I cannot believe that the bottles and cockpit all came pre stuffed on a single sub assembly. As such one would expect some sort of integration test after hook up.

I thought I read somewhere in this thread that they ARE tested, but that the test MAY NOT catch a reversal of the wiring. In other words, the test shows that "a" bottle will fire (poor terminology - I'm no engineer) but perhaps not say WHICH bottle.

-Dave

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-20 23:15:37 and read 7903 times.

Quoting hivue (Reply 141):
I believe the reports are saying the problem is in the extinguisher assemblies themselves. I would think that crossed wires in the bottles would be adequate explain the problem.

Well the first thing is, "the problem" is still not precisely defined, as are its consequences.
Second thing is, where is the limit of the exitnguisher assembly ? What exactly is assembled by the supplier in terms of wiring ? Based on the "suppliers are in charge of full systems" policy, it could be that the supplier delivers the bottles including the "terminal" wiring to the RDCs (the discrete signal lines I was talking about). So the "wiring within the assembly" could very well be those last few meters of command signal lines. The rest of the signal path (AFDX network/CCS/cockpit panels & displays) would be under Boeing responsibility, and that seems to be working.

But again, I'm not sure about anything here. These are just WAGs based on my general knowledge.
So there I am with more questions  
Quoting StTim (Reply 140):
not impossible to design around but at some point the cost of pipework, fixings, extra bottle capacity (there will be some loss in the pipework) will negate the simplicity of design and extra weight of bottles at the engone.

Sure, but keep in mind other systems have had pipes and wires going to & from the engines for a long time without major issues regarding UERF : bleed ducts, hydraulic lines, electric power cables, data lines. And regarding redundancy (for safety purposes  ), you change from 2x2 bottles to 1x2, albeit slightly bigger bottles. There might be other advantages too, like in terms of maintenance, for example.

This may have seemed to be slightly off topic, but my goal is to point out that system architectures are changing.
With the newest planes, it is not possible to simply assume that the systems are built in exactly the same way as 30 or 40 years ago, apart from the replacement of bleed by electricity. The digital design tools have opened up a lot of new options, by enabling engineers to get rid of huge margins necessary to compensate for the many unknowns. So there are much more options to choose from.
One cannot simply say "that's how the systems work on 767/A330/... so that's how they work on 787/A350/...". If there is a problem, the first order of business is to understand how exactly the system is designed before jumping to conclusions. Unfortunately, that step was missed in this thread. This is not obvious stuff, especially for non-system engineers, so I am not trying to blame anyone here. Just saying that we should take a step back, take a deep breath, and list what we know exactly regarding the system and the failure. As I wanted to point out, the answer to that is : very little.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Tristarsteve
Posted 2013-08-21 10:27:39 and read 7664 times.

Quoting kanban (Reply 139):
.. it appears that the bottles are in the wheel wells

No they are in the sidewall of the fwd freight hold. Two engine bottles and the Seven cargo bottles are all in one line along the right hand of the fwd freight hold. Same place as B777.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-21 10:43:39 and read 7625 times.

Quoting Tristarsteve (Reply 144):
No they are in the sidewall of the fwd freight hold.

good to know.. years ago I would have popped down to the line and looked myself. Thanks

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Klaus
Posted 2013-08-22 12:00:49 and read 7386 times.

From my point of view (I'm developing non-aviation (mostly) digital systems as part of my work) it doesn't matter to the defect whether direct wiring or bus-based addressing is used.

Testing is rather simple by using a dummy load (the above mentioned "test box") and just pulling and rotating the fire handles, while observing the effect on the squibs and valves.

The problem in this case may have been (if the 777 diagram does indeed apply to the 787 as well):

• the bottles being not located at the actual engines (which would have made it trivial to check if the proper engine would be affected) but in the fuselage

• each bottle supplying both engines

• the only difference being in the valves distributing the emerging gas, and those valves likely being close to each other near the respective bottle (are they labeled? are the actual valves checked for activation as well or just the connectors the valves are plugged into?)

• absolutely precise communication between the cockpit operator and the valve-observing colleague seems essential here ("yeah, one valve activated, yeah, now the other!" could be a problem instead of "bottle 1 fired, valve to right engine opened")

I would like to know how exactly that test is supposed to be conducted, but while I see the redundancy advantages of two bottles supplying both engines, this design has a high potential for confusion and even a tiny lack of attention under pressure or with some fatigue easily leading to unreliable test results.

It might be desirable to have the test boxes transmitting the actual signal state at the bottles and valves to the cockpit to eliminate human communication errors if that isn't done already.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: asctty
Posted 2013-08-23 11:58:11 and read 7153 times.

I have been reading through all these posts and grimacing.

Do any any of those posting on here understand the concept of 'Safety Critical Systems' and why more rigour is required to ensure that the safety systems meet the design intent? If a system is designed to extinguish a fire, then it must be proven to do so.

Now. before you all start saying that this is totally impractical, lets be clear what this means in reality:

The capacity of the fire extinguisher itself must be accurately calculated. In this case I would expect this evolution to be conducted by the fire protection supplier and the engine suppler.

After this the fire detection system would be designed. This would involve the above suppliers and of course Boeing.

Then the system would be factory tested all the way up to, BUT NOT INCLUDING the firing of he fire suppression cylinders themselves.

Somewhere during this simple test of the system, it should have become blatantly obvious if some wires in the system has been crossed. The bottles themselves have no control function/wires!

If after factory acceptance, the wires become crossed, then this can only happen by intervention by either Boeing before Delivery, or the maintainers afterwards.

I AM a Safety Engineer who is not too comfortable with the official reports so far.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Klaus
Posted 2013-08-24 14:06:43 and read 6903 times.

Quoting asctty (Reply 147):
Somewhere during this simple test of the system, it should have become blatantly obvious if some wires in the system has been crossed. The bottles themselves have no control function/wires!

I've tried to address exactly the "blatantly obvious" point above.

If there was one bottle in each engine, you would be right.

But that is not the case, apparently, and for redundancy that is indeed a good choice.

The trouble with that design is that the selection of the right or left engine to extinguish is no longer quite as "blatantly obvious" since each bottle in the fuselage has two valves for both engines which are likely close to each other – it is no longer quite that simple or obvious to test which engine would have received the gas. And even if the plugs of these valves were pulled, the wiring from the valves to the socket would still need to be validated on top of the main test.

The testing procedure and the auxiliary devices used in this test must very deliberately address that potential for confusion, and that can be a matter of cost and time during design and potentially during the tests as well.

From the results it seems the test design was flawed – given the system design I suspect that they actually relied on verbal communication between two workers (probably via radio) to verify whether the correct bottle fired and whether the correct engine did indeed receive its output.

This would be a "quick and dirty" kind of test which would be highly susceptible to errors caused by fatigue and stress; Given the history of the 787 project I wouldn't be surprised if they were simply cutting corners there.

A proper test would take some more effort to design (you'd need automated feedback to the cockpit through wires or reliable data transmission, including additional measures to prevent malfunctions of that more complex testing gear), but it would be more reliable and should practically eliminate this type of mistake.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: hivue
Posted 2013-08-24 19:32:15 and read 6694 times.

Quoting Klaus (Reply 148):
The bottles themselves have no control function/wires!

How do you know this? The current reports are that the problem was with the extinguisher manufacturer and not Boeing. If this is correct, then for it to be a crossed wiring issue the extinguisher assemblies would need to contain wiring.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-25 01:54:16 and read 6569 times.

Quote:
"blatantly obvious"

It is only "blatantly obvious" because I think you two are again making assumptions on the system architecture without realising it....
Just as many seemed to erroneously assume that the bottles were installed near each engine, now you are assuming that the control valves are installed near the bottles, or at least somewhere where they can easily be checked.
This may be true, and it is indeed what is suggested by the 777 diagram that I posted. But beware, that is a functional diagram from the FCOM, meant to show the pilots the general principle of operation. It does not necessarily reflect the actual physical layout of the system - that information would more likely be found in the AMM, for those who need to repair the system, not use it.
Without looking too much into it, I could imagine at least 4 physical architectures to link the 2 bottles and the 2 engines :
1) 4 complete bottle-to-engine pipe systems, with 2 valves per bottle installed on the bottles
2) 2 bottle assembly to engine systems, one per engine. A collector pipe for each engine runs near the bottles, with a small branch to connect it to each bottle. Again, 2 valves per bottle, installed on the bottles
3) 2 bottle assembly to engine systems, one per bottle. Each bottle is connected to a single collector pipe, which then divides towards each engine. The division (and associated valves) would likely be somewhere around the wing box area. 2 open/close valves on the bottles + 2 division vales to direct the flow towards the engines
4) 1 common system, with both bottles linked to a same collector, which divides further downstream towards each engine. Again, a 2+2 valve assembly

Some of these solutions may not be usable due to redundancy issues or whatever. But that's not my point : what I want to say is that depending on the actual implementation, the valves are not necessarily easy to access and check. And as we have no idea so far of which solution is actually used, there is no point in accusations of missing "blatantly obvious" things.



Quoting Klaus (Reply 148):

The testing procedure and the auxiliary devices used in this test

Do you positively know of a test, or is this another supposition ? It seems this is a one-off incident, which would tend to indicate a production quality issue, not a design quality issue.
The difference is, design quality is test driven to make sure of the system behaviour in most foreseeable circumstances. That is the point of all those flight tests, ground tests, simulatoirs and stuff used during the development phase. Production quality is more process-driven, ie you assemble your parts in a way which is supposed to guarantee the final product is the same every time. Testing is not necessarily used, and if it is, it will be quick and simple tests of the complex, error-prone items. Not in depth tests, or tests of what is supposed to be simple stuff.

Quoting asctty (Reply 146):
I AM a Safety Engineer who is not too comfortable with the official reports so far.

Then you'd know far better than I do that system saftey assesment starts with a long hard look at what actual information is available, how reliable that info is, and what info is needed but not available.
Regarding what info we have, it is very little, mostly newspaper articles of dubious reliability (and not official reports). And as I have tried to make clear, the amount information we need to make any conclusion, but that we do not have, is huge.

Once more, yes there was a problem, yes it was serious and yes it must be corrected. But no, there is no reason to think that Boeing is sitting on the issue, and no, there is no reason to believe this issue illustrates a (another...) systemic failure of Boeing and the 787 program management.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-25 09:49:19 and read 6372 times.

Quoting airmagnac (Reply 150):
But no, there is no reason to think that Boeing is sitting on the issue, and no, there is no reason to believe this issue illustrates a (another...) systemic failure of Boeing and the 787 program management.

so easy to toss negative comments when in fact the system is identical to the one on the 777.. (another "systematic failure" that has had no problems with the system. Second the supplier admitted creating the error during maintenance/upgrade, so how is it's Boeing's error? Does Boeing QA buy off all airline maintenance work or all supplier maintenance work after delivery? Heck no!

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Tristarsteve
Posted 2013-08-25 12:03:49 and read 6328 times.

Quoting airmagnac (Reply 150):
2) 2 bottle assembly to engine systems, one per engine. A collector pipe for each engine runs near the bottles, with a small branch to connect it to each bottle. Again, 2 valves per bottle, installed on the bottles

This is nearest.
The two bottles are fitted beside each other in the freight hold sidewall.
Each bottle has two squibs (not valves, squibs are explosive devices)
Under the bottles are two pipes, one leading to each engine, and one stub pipe runs from each bottles to each engine pipe.
To test the circuit you need a B787 Fire extinguishing system squib test set.
You disconnect the four squibs and connect them two at a time to the test set and operate the fire handle in the flight deck and see what happens.
No idea how often this is done, but something like once a year?

And this type of system was fitted to the B737-200, but with the bottles in the wheel bay, so Boeing has a little experience of it!

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: ODwyerPW
Posted 2013-08-25 12:23:09 and read 6281 times.

Kanban,
Thanks for your continued insights. They really help to add a bit of clarity to each of these issues.
Peter

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-25 12:44:34 and read 6246 times.

Quoting kanban (Reply 151):
so easy to toss negative comments when in fact the system is identical to the one on the 777.. (another "systematic failure" that has had no problems with the system. Second the supplier admitted creating the error during maintenance/upgrade, so how is it's Boeing's error?

I personally do not blame Boeing for the error if in was / is indeed proven the error should have been caught by the supplier's QA, and there way no way for Boeing to know about it.

However my issue remains Boeing's unnecessary and defensive official remark (and defenses of this by various a.netters) that this miswiring did not create a safety risk. Yes there is redundancy, but this miswiring certainly did create an increased safety risk.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: yeelep
Posted 2013-08-25 14:32:41 and read 6128 times.

Quoting Tristarsteve (Reply 152):
And this type of system was fitted to the B737-200, but with the bottles in the wheel bay, so Boeing has a little experience of it!

The 737-200 system uses one squib per bottle with a selector valve to direct the extinguishant to the selected engine. The 737 Classic uses two squibs per bottle in the manner you described and airmagnac's 777 FCOM diagram in reply 131 shows.
A article of the different ways a engine fire is avoided or dealt with.
http://www.boeing.com/commercial/aeromagazine/articles/2010_q4/3/

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-25 15:09:45 and read 6087 times.

Quoting sankaps (Reply 154):
However my issue remains Boeing's unnecessary and defensive official remark (and defenses of this by various a.netters) that this miswiring did not create a safety risk. Yes there is redundancy, but this miswiring certainly did create an increased safety risk.

I would consider a greater safety risk an event where they were unable to cut off the fuel to a damaged or burning engine. the extinguisher is a one shot attempt (well maybe two shot).. However seeing fire departments having to spray foam into a running engine because it could not be shut down brings my level of panic up.

Not every cock-up is caught no matter how vigilant the manufacturer, assembler, operator, or builder is, the advantage is with the multiple layers it gets caught often without press paranoia or sensationalism and the public goes winging there way safely anyway. There is a point where knowing is the booby prize.. one takes the awareness and either wants change, attempts change or worries themselves to an early grave.

Planes can be dispatched with some brakes inoperative.. to a lawyer wanting a big paycheck the redundancy has been sacrificed, to the FAA and NTSB, the remaining system is still within the designed safety limits...

Quoting yeelep (Reply 155):
A article

nice article.. won't satisfy everybody, but it helps.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Klaus
Posted 2013-08-25 15:46:25 and read 6041 times.

Quoting hivue (Reply 149):
How do you know this?

That was not from my post but from me quoting asctty:

Quoting Klaus (Reply 148):
Quoting asctty (Reply 147):
Somewhere during this simple test of the system, it should have become blatantly obvious if some wires in the system has been crossed. The bottles themselves have no control function/wires!
Quoting airmagnac (Reply 150):
Do you positively know of a test, or is this another supposition ?

I think I have properly qualified where I've used conjecture.

The single-line design with valves close to the bottles seemed the most plausible, all considered.

Quoting airmagnac (Reply 150):
It seems this is a one-off incident, which would tend to indicate a production quality issue, not a design quality issue.

Weren't there multiple incidents reported from different airlines?

Quoting airmagnac (Reply 150):
Testing is not necessarily used, and if it is, it will be quick and simple tests of the complex, error-prone items. Not in depth tests, or tests of what is supposed to be simple stuff.

"Not necessarily"? I would consider testing absolutely mandatory on safety-essential systems, particularly including a proper post-integration check of the finished product by the manufacturer – in this case Boeing.

Quoting airmagnac (Reply 150):
Once more, yes there was a problem, yes it was serious and yes it must be corrected. But no, there is no reason to think that Boeing is sitting on the issue, and no, there is no reason to believe this issue illustrates a (another...) systemic failure of Boeing and the 787 program management.

It may not, but if post-integration testing was indeed neglected or designed unreliably, then it still might.

Quoting kanban (Reply 151):
Second the supplier admitted creating the error during maintenance/upgrade, so how is it's Boeing's error? Does Boeing QA buy off all airline maintenance work or all supplier maintenance work after delivery? Heck no!

Are you saying that a major miswiring in a safety-critical system on a freshly manufactured aircraft remaining undetected beyond delivery was a non-issue?

Quoting Tristarsteve (Reply 152):
This is nearest.
The two bottles are fitted beside each other in the freight hold sidewall.
Each bottle has two squibs (not valves, squibs are explosive devices)
Under the bottles are two pipes, one leading to each engine, and one stub pipe runs from each bottles to each engine pipe.

Ah, thank you. So there are no distribution valves any more. Okay. Just two components per bottle instead of three – probably not a bad idea by itself.

Quoting Tristarsteve (Reply 152):
To test the circuit you need a B787 Fire extinguishing system squib test set.
You disconnect the four squibs and connect them two at a time to the test set and operate the fire handle in the flight deck and see what happens.

That was my point above: "You" being one guy in the cockpit plus one guy at the bottle observing the effects and communicating them to the other guy? How so, exactly?

And do the two squibs per bottle have one shared connector or do they have separate ones?

Do you know if the "miswiring" was the two separate connectors accidentally being plugged in to the wrong squibs or was it an actual miswiring within the cable harness?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-25 17:11:57 and read 5987 times.

Quoting Klaus (Reply 157):
Are you saying that a major miswiring in a safety-critical system on a freshly manufactured aircraft remaining undetected beyond delivery was a non-issue?

I'm saying you can keep beating a dead horse and Boeing will never reinspect a supplier's post delivery maintenance work. There has been no evidence that the planes were delivered this way and the vendor of the specification controlled system says it happened after Boeing installation.

Quoting Klaus (Reply 157):
That was my point above: "You" being one guy in the cockpit plus one guy at the bottle observing the effects and communicating them to the other guy? How so, exactly?

commonly done by banging on the nearest floor beam with a big rock... actually through either radio or system inter phones.. although in this day and age, the guy in the hold probably is connected to the electronic test plan and clicks the "LIKE" button if everything works as planned.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: hivue
Posted 2013-08-25 19:21:22 and read 5885 times.

Quoting Klaus (Reply 157):
That was not from my post but from me quoting asctty:

My apologies. I was intending to quote asctty.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Klaus
Posted 2013-08-26 10:43:04 and read 5682 times.

Quoting kanban (Reply 158):
I'm saying you can keep beating a dead horse and Boeing will never reinspect a supplier's post delivery maintenance work. There has been no evidence that the planes were delivered this way and the vendor of the specification controlled system says it happened after Boeing installation.

Wait a second – has there been any post-delivery reworking of the fire suppression systems on the affected aircraft? This is the first I hear of this!

Given the low age of the aircraft, I would rather expect those systems to still be in their original delivery state.

Or do you have any information to the contrary?

Quoting kanban (Reply 158):
commonly done by banging on the nearest floor beam with a big rock... actually through either radio or system inter phones.. although in this day and age, the guy in the hold probably is connected to the electronic test plan and clicks the "LIKE" button if everything works as planned.

The crucial point here is whether the validity of the test relies inherently on aural communication between two workers within a noisy environment or if one of them directly knows both the position of the fire handle by his/her own action and the exact and reliable reaction of each squib by technical means at the same time.

This makes a major difference to the reliability of such a test, and is one of the things which would have been designed into that test – at a corresponding cost in time and money (although most likely just a fraction of the total cost of the retroactive checks now!).

Quoting hivue (Reply 159):
My apologies. I was intending to quote asctty.

No problem.

[Edited 2013-08-26 10:45:36]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-26 10:50:58 and read 5664 times.

Quoting Klaus (Reply 160):
he crucial point here is whether the validity of the test relies inherently on aural communication between two workers within a noisy environment or if one of them directly knows both the position of the fire handle by his/her own action and the exact and reliable reaction of each squib by technical means at the same time.

OK, my sarcasm missed.. actually they are on a closed communications system with headsets and mikes.. Plus the production line/field testing areas are a lot quieter than people outside the industry would believe.

Re: post assembly work, I can't find the reference but it was in a UTX communication.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-26 11:18:36 and read 5618 times.

Quoting kanban (Reply 156):
Planes can be dispatched with some brakes inoperative.. to a lawyer wanting a big paycheck the redundancy has been sacrificed, to the FAA and NTSB, the remaining system is still within the designed safety limits...

Sure, but engine fire bottles are not a MEL-able item, and revenue pax flights cannot be dispatched with them inoperative. This is because it is considered a safety issue. That is my only point, I am not blaming Boeing for the issue occurring (we need to understand how it occurred first), but am taking exception to them claiming this was not a safety issue.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-26 11:37:16 and read 5593 times.

Quoting kanban (Reply 156):
Planes can be dispatched with some brakes inoperative.. to a lawyer wanting a big paycheck the redundancy has been sacrificed, to the FAA and NTSB, the remaining system is still within the designed safety limits...

What you do not mention is that prior to dispatch the crews would have made an assessment that the airports that are intended for use for the flight would have the required runway length, plus the safety factors based upon those brakes being inoperative. I.e. the new data is based upon those brakes being inoperative.

The new distance required = (required braking distance with inop brakes x safety factor) which is greater than (required braking distance with all brakes x safety factor)

The additional safety distance is increased with inop brakes.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-26 18:05:42 and read 5376 times.

Quoting zeke (Reply 163):
What you do not mention

Thanks for the detail Zeke.. that's why having a pilot on the forum is valuable..

Maybe you can from experience tell us about how often the fire bottles are discharged and after discharge and having cut the fuel flow, how dangerous the situation remains.. also if the fire bottle does not quell the fire how long would there be a problem with no fuel available ..

I'm thinking Boeing's comment related to other means of isolating and starving any fire as well as fire isolation by design as being the redundant system, rather than having endless fire bottle releases.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: 7BOEING7
Posted 2013-08-26 20:03:59 and read 5274 times.

Quoting kanban (Reply 164):
I'm thinking Boeing's comment related to other means of isolating and starving any fire as well as fire isolation by design as being the redundant system, rather than having endless fire bottle releases.


During a Fire Warning you cutoff fuel to the engine with the Fuel Control switch then pull the Fire Switch which shuts off fuel, bleed air, engine generators and hydraulic fluid. This is expected to remove most if not all reasons for a Fire Warning. If the Fire Warning is still showing you discharge one fire bottle and then 30 seconds later the other fire bottle -- after that you're on your own. This is basically the same on all Boeing airplanes. The two times in over 30 years I had a Fire Warning and discharged a bottle there was no fire, it was a false indication -- bad cards (744 & 763). Engine fire switches are routinely pulled during B-1/C-1 profiles to confirm normal operation.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-26 20:47:09 and read 5240 times.

Quoting 7BOEING7 (Reply 165):
.

If I understand correctly, first you shut off all sources of fuel for the fire.. so without fuel it will burn itself out.. however if for some reason there is a reservoir of combustibles remaining, you fire the bottles.. .. that plus the strut design adds firewalls, heat shields and the open venting of areas where combustibles might gather limits the duration and any damage a fire might cause..

While I'm glad there are fire extinguishing bottles in the system, it sounds like they are the redundancies not the other way around.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-26 21:07:28 and read 5236 times.

Quoting kanban (Reply 166):
If I understand correctly

Not really, have a look at where the fire loops are, and where the fire extinguishing agent goes. When a bottle is fired off, you are not throwing agent into the engine core.

The engine core itself is designed to contain a fire (the combustor) under normal conditions.

http://www.boeing.com/commercial/aeromagazine/articles/2010_q4/3/

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-26 22:25:14 and read 5160 times.

A fire in the core if deprived of material to sustain itself, will go out... if the fire is outside the core, again the depravation of 'fuel' limits it's ability to spread, the extinguishing agent would fill the spaces around the core and in the strut identified as flammable material leakage zones.

So 7BOEING7 has discharged them twice due to a circuit card error, has any other pilot discharged them either because of a fire or because the detectors indicated there was one? thee question is to gain knowledge from those dealing with real situations versus armchair worriers theoretical situations.

Zeke, do you have confidence the system working as designed?

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-27 01:25:55 and read 5018 times.

Quoting kanban (Reply 168):
thee question is to gain knowledge from those dealing with real situations versus armchair worriers theoretical situations.

Zeke, can you also share your views on what it might be like / the risks it might entail if a pilot fires the fire bottle in a real fire, but for some reason it appears the bottle for the good engine fired instead of the one for the engine that is actually on fire? How long would it take for the pilot to find out that this is what happened? Would that cause any confusion or delay in handling the situation, or would it be brushed off by pilots as "no big deal, these things happen, nothing to do with safety".

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: 7BOEING7
Posted 2013-08-27 09:44:11 and read 4733 times.

Quoting sankaps (Reply 169):
How long would it take for the pilot to find out that this is what happened?


If the pilot got to the point in the checklist where the fire bottle is discharged he would have an indication it discharged but no indication it went into the "wrong" engine -- the "wrong" engine would continue working normally. If a passenger was looking at the back of the "wrong" engine he might notice it -- the ground crew will certainly notice it.

Quoting sankaps (Reply 169):
Would that cause any confusion or delay in handling the situation, or would it be brushed off by pilots as "no big deal, these things happen, nothing to do with safety".


After 30 seconds if there was still an engine fire indication the pilot would discharge the second bottle and "plan to land at the nearest suitable airport". There wouldn't be any confusion or delay but I don't think any pilot would consider it as "no big deal .....".

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-27 09:47:28 and read 4717 times.

Quoting 7BOEING7 (Reply 170):
If the pilot got to the point in the checklist where the fire bottle is discharged he would have an indication it discharged but no indication it went into the "wrong" engine -- the "wrong" engine would continue working normally. If a passenger was looking at the back of the "wrong" engine he might notice it -- the ground crew will certainly notice it.
Quoting 7BOEING7 (Reply 170):
After 30 seconds if there was still an engine fire indication the pilot would discharge the second bottle and "plan to land at the nearest suitable airport". There wouldn't be any confusion or delay but I don't think any pilot would consider it as "no big deal .....".

Thanks. Therefore there is a safety implication if this were to happen. That is all I wanted to confirm.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-27 10:15:23 and read 4673 times.

Quoting sankaps (Reply 162):
am taking exception to them claiming this was not a safety issue.

You are only looking at the fire extinguishing system in isolation of everything else. It is in fact only one element of multi-layered defense against engine fire, as a few posts above have pointed out.
As you may have noticed in the article linked by Zeke, the focus is not on fire extinguishing but on the wider notion of fire protection. The ultimate goal (what is called "function" in systems engineering) is to protect the aircraft from fire.
This function is fulfilled by several preventive layers, aiming to avoid a fire in the first place, and several reactive means, to contain and eventually actively extinguish a fire if the prevention layers failed.
Concretly, this is implemented by a combination of specific design elements within the engines/APU/other, and of several systems fully dedicated to the function, including active ones (extinguisher, detection...) and passive ones (linings, fire walls...). And the article does not mention the pilots, which could be seen as an active reactive system by deciding to divert in case of a fire.

And why would any of the defense layers fail ? Simply because we are imperfect human beings, and we make mistakes : design errors by engineers, manufacturing & assembly errors (like we seem to have here), operational errors (the infamous "pilot error") or maintenance errors.
We are also not omniscient, and sometimes a defense layer may not extend far enough to cover all possible failures. This seems to be the case of the battery a few months back : the battery and electrical system are supposed to be designed to avoid a thermal runaway in the first place. Alas, for a reason that remains unknown (AFAIK), it happened. But the reactive layers (containement of the battery, ventilation, emergency landing decision by the pilot...) did their job (although there were flaws) and in the end no one was hurt.

So if for any of these reasons, one of the defense layers fails, there will be another, or others, to back it up and avoid a disaster. Therein lies the subtlety of these damage-tolerant designs : you cannot de-activate any of the defense layers voluntarily (ie no dispatch under MEL), but if any layer does get involuntarily "de-activated" by some kind of error, it does not necessarily have to be an immediate safety issue. For an accident to happen, several layers have to fail at the same time. Or using another frequent image, the holes in the layers of cheese have to line up.


Please understand that I am not shrugging this issue off as insignificant. But there are numerous shades of gray between "insignificant event" and "safety critical event requiring immediate action", and to each shade there is an appropriate, measured solution. Taking extreme measures for any problem would actually go against safety, as the real immediatly-safety-critical issues would be lost in the overwhelming flow of other less dangerous problems.

Quoting Klaus (Reply 157):
Weren't there multiple incidents reported from different airlines?

As far as I have seen in the links posted in this thread, there was 1 JAL aircraft impacted ; maybe 1 UA (but this seems to be an error by the WSJ) ; and otherwise a "limited number" of assemblies, as per the supplier.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: kanban
Posted 2013-08-27 10:35:51 and read 4643 times.

Quoting airmagnac (Reply 172):
You are only looking at the fire extinguishing system in isolation of everything else. It is in fact only one element of multi-layered defense against engine fire, as a few posts above have pointed out.
As you may have noticed in the article linked by Zeke, the focus is not on fire extinguishing but on the wider notion of fire protection. The ultimate goal (what is called "function" in systems engineering) is to protect the aircraft from fire.

     

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-27 11:09:19 and read 4573 times.

Quoting airmagnac (Reply 172):
Please understand that I am not shrugging this issue off as insignificant. But there are numerous shades of gray between "insignificant event" and "safety critical event requiring immediate action", and to each shade there is an appropriate, measured solution.

I fully understand and appreciate your comment. However even with what you say above, I submit it was disingenuous for Boeing to state in a pretty much black and white manner that the miswired bottles did not present a safety issue, without acknowledging the shades of gray in between.

Unless the condition is known in advance, and pilots are briefed, it IS a safety risk to have the wrong engine's bottles firing in case of an actual engine fire.

Furthermore, I submit that miswired or inoperable engine fire bottles (even if the condition were known in advance) would not be a NO GO item if it presented no safety risk at all.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: PITingres
Posted 2013-08-27 11:47:46 and read 4520 times.

Quoting sankaps (Reply 174):
I submit it was disingenuous for Boeing to state in a pretty much black and white manner that the miswired bottles did not present a safety issue, without acknowledging the shades of gray in between.

To be fair, I believe that quote I saw (which I don't have time to find and link to, but I'm pretty sure it was referenced in this thread already) was along the lines of "There was no immediate safety of flight issue." I suspect that what they were trying to say was that the error would not in and of itself have been enough to make the plane drop out of the sky. Which is true enough. If your argument is that they would have done better to either say nothing, or make a less ambiguous statement without trade jargon, then I agree.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: Stitch
Posted 2013-08-27 12:04:26 and read 4510 times.

Quoting PITingres (Reply 175):
To be fair, I believe that quote I saw (which I don't have time to find and link to, but I'm pretty sure it was referenced in this thread already) was along the lines of "There was no immediate safety of flight issue."

That is pretty much correct, as referenced in an article in the WSJ dated August 16, 2013:

Quote:
The plane maker said in a written statement that the improper assembly, which has been confirmed to have been found on three All Nippon Holdings jets in Japan, "does not present a safety of flight issue because the bottles are not the only means of fire extinguishing for engines and there are multiple redundancies within the fire extinguishing system.


[Edited 2013-08-27 12:28:46]

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: sankaps
Posted 2013-08-27 12:11:02 and read 4540 times.

Quoting PITingres (Reply 175):
To be fair, I believe that quote I saw (which I don't have time to find and link to, but I'm pretty sure it was referenced in this thread already) was along the lines of "There was no immediate safety of flight issue." I suspect that what they were trying to say was that the error would not in and of itself have been enough to make the plane drop out of the sky. Which is true enough.

The actualy quote as reported in the Wall Street Journal was "The plane maker said in a written statement that the improper assembly, which has been confirmed to have been found on three ANA jets in Japan, "does not present a safety of flight issue because the bottles are not the only means of fire extinguishing for engines and there are multiple redundancies within the fire extinguishing system."

My reading of this, and the reference to redundancies, suggests that Boeing is saying that even if the bottles had to be used in-flight in response to an actual engine fire, there would not be a safety of flight issue because of the redundancies.

And this is what I fundamentally disagree with for all of the reasons discussed earlier.

Quoting PITingres (Reply 175):
If your argument is that they would have done better to either say nothing, or make a less ambiguous statement without trade jargon, then I agree.

Precisely. They should have just not made any reference to safety, perhaps just said there are redundant systems in case of a fire and leave it at that.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: airmagnac
Posted 2013-08-27 12:19:40 and read 4514 times.

Quoting sankaps (Reply 174):
I submit that miswired or inoperable engine fire bottles (even if the condition were known in advance) would not be a NO GO item if it presented no safety risk at all.

The important point is the "known in advance" part. It's not : it would be NO GO "even" if the condition were known, but rather it would be NO GO "especially" if it were known.

You cannot knowingly dispatch with faulty wiring ; but if it is not known that the wiring is faulty and the aircraft is dispatched, it does not present by itself an immediate safety risk. For sure, the issue must be detected and corrected as soon as possible, and there are techniques and methods to enhance detection capabilities.
And it appears this was done in this case. The problem was somehow found, and it seems that once the issue was known, airlines and Boeing immediatly took action to correct it, and therefore to avoid dispatching aircraft with a known fault.

Quoting sankaps (Reply 174):
it was disingenuous for Boeing to state in a pretty much black and white manner that the miswired bottles did not present a safety issue
Quoting sankaps (Reply 174):
it IS a safety risk

I think that at this point we are facing a semantics problem regarding the definition of "safety issue", "safety of flight" and the interpretation of the Boeing statement. First there is the issue of the exact wording, as pointed out above.
Even then, what you say can be considered true as is; but so can the Boeing statement.
It really depends on how you want to read the problem. A layman, a Boeing stockholder, you, me as an engineer with my backside comfortably installed in a chair, and a 787 pilot-in-command, may have wildly differing opinions, none of which is "more true" than another, unless we have some hard detailed facts.

The less information we have, the wider the range open for interpretation...which is why I insist on obtaining sufficient reliable information before attempting to reach any kind of conclusion.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-27 14:15:53 and read 4395 times.

Quoting sankaps (Reply 169):
Zeke, can you also share your views on what it might be like / the risks it might entail if a pilot fires the fire bottle in a real fire, but for some reason it appears the bottle for the good engine fired instead of the one for the engine that is actually on fire?

I cannot say with certainty, however the agent normally goes into areas which are not supposed to be on fire. Those areas are not pressurised, the systems in those areas are designed to operate in the hot/cold/wet/dry. Not sure what effect some "inert" gas effectively is going to do to the operation of the engine. We normally wait a period of time before putting the first agent into an engine to improve the effectiveness.

Quoting sankaps (Reply 169):
How long would it take for the pilot to find out that this is what happened?

You have no indication where an agent is delivered. With QF32 and the Asiania crash, the crew in both cases thought they fired the bottles, however the circuits were not complete.

Quoting sankaps (Reply 169):
Would that cause any confusion or delay in handling the situation, or would it be brushed off by pilots as "no big deal, these things happen, nothing to do with safety".

When talking about fires, people normally use the "fire triangle" principle, fire needs three things, heat, fuel, and air. The agent is there to remove the air temporarily to put the fire out, it does not remain in the area for extended period of time. Other parts of the checklist deal with removing fuel from the triangle, and with the fire out for a little, the heat is also removed with the air stream. The engine/pylon is also designed in "compartments" to contain the fire and prevent it from moving further.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: yeelep
Posted 2013-08-28 09:33:04 and read 4136 times.

Quoting zeke (Reply 179):
The agent is there to remove the air temporarily to put the fire out, it does not remain in the area for extended period of time.

The most popular agent for use on engines is Halon 1301. It does not put out fire by removing air, it chemically reacts with and interrupts the fire. Less than 8% Halon by volume is needed to extinguish a fire.

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: zeke
Posted 2013-08-28 11:22:56 and read 4050 times.

Quoting yeelep (Reply 180):

Thanks, I learnt something  

Does Halon remove oxygen from the air?

It is a common misconception that Halon, like CO2, "removes oxygen from the air."

According to the Halon Alternative Research Corporation (www.harc.org): "Three things must come together at the same time to start a fire. The first ingredient is fuel (anything that can burn), the second is oxygen and the last is an ignition source. Traditionally, to stop a fire you need to remove one side of the triangle-the ignition, the fuel or the oxygen. Halon adds a fourth dimension to fire fighting-breaking the chain reaction. It stops the fuel, the ignition and the oxygen from working together by chemically reacting with them."

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: NeutronStar73
Posted 2013-08-28 12:14:46 and read 3973 times.

Quoting Grisee08 (Reply 51):
I am sort of wanting to fly on a 787 just to check it out, but each time I consider it, I am going more and more towards not doing it at all. I may wait a few years until all the kinks are worked out. I would hate to buy a ticket just to fly on a 787, only to show up and it be replaced with a 767 or 777. Methinks UA will be keeping these birds on more domestic routes than originally planned for a little bit longer.

Do you have the same level of fear or trepidation when it comes to driving or riding in a Toyota? Cause we all know the issues they had/have with unintended acceleration or WOT situations where there were deaths involved.  

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: PlanesNTrains
Posted 2013-08-28 12:54:11 and read 3897 times.

Quoting NeutronStar73 (Reply 182):
Do you have the same level of fear or trepidation when it comes to driving or riding in a Toyota? Cause we all know the issues they had/have with unintended acceleration or WOT situations where there were deaths involved.

It's hard to criticize how someone personally feels. While I don't "fear" flying on a 787 (though I doubt I'll have the opportunity anytime soon), I can't say as though the thoughts wouldn't cross my mind while sitting in my seat either. The fact of the matter is, the 787 has been plagued by things that have raised a few eyebrows. If you would put your loved ones on the plane without giving it a second thought, fine, but some might not.

To be fair, when I put my son solo on a JetBlue A320 the other night, I had thoughts of "what if?" - not because the A320 or JetBlue are unsafe in any way, but because I'm human, I care about my loved ones, and I want to make the best decisions for their safety.

-Dave

Topic: RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs
Username: rcair1
Posted 2013-08-29 10:06:57 and read 3595 times.

Quoting zeke (Reply 181):
According to the Halon Alternative Research Corporation (www.harc.org): "Three things must come together at the same time to start a fire. The first ingredient is fuel (anything that can burn), the second is oxygen and the last is an ignition source. Traditionally, to stop a fire you need to remove one side of the triangle-the ignition, the fuel or the oxygen. Halon adds a fourth dimension to fire fighting-breaking the chain reaction. It stops the fuel, the ignition and the oxygen from working together by chemically reacting with them."

The fire triangle is an outmoded discussion we do not use in fire fighting anymore,

We use a fire tetrahedron - which includes "Continuous Chemical Reaction". Halon attacks that.


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