sankaps
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ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 9:06 am

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...
 
AA737-823
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 9:25 am

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.
 
planewasted
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 9:46 am

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.
 
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larshjort
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 10:00 am

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.

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speedbored
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 10:18 am

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.
 
Grisee08
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:05 am

...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?
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flood
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:26 am

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
 
RedChili
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:31 am

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...
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speedbored
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:38 am

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.
 
StTim
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:38 am

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?
 
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speedbored
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:45 am

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.
 
planewasted
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:46 am

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]
 
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BoeingVista
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:51 am

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]
BV
 
Tristarsteve
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:52 am

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.
 
StTim
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 11:54 am

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.
 
PHX787
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:06 pm

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.
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wingman
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:12 pm

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.
 
spacecadet
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:19 pm

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.
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:25 pm

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.
 
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TheRedBaron
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:32 pm

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.
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SonomaFlyer
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:49 pm

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.
 
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:51 pm

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.
 
StTim
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 3:59 pm

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.
 
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:02 pm

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]
 
JRenavitz
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:04 pm

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.
 
RedChili
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:11 pm

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.
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:13 pm

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]
 
StTim
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:14 pm

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.
 
brilondon
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:15 pm

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?
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:16 pm

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]
 
mats01776
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:17 pm

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.
 
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:23 pm

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.
 
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KarelXWB
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:34 pm

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]
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rheinwaldner
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:35 pm

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....
 
mats01776
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:38 pm

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.
 
yeelep
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:40 pm

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.
 
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:44 pm

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.
 
yeelep
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 4:46 pm

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.
 
dtw2hyd
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 5:01 pm

May be 787 will the first aircraft to get "D check on delivery" distinction.
 
Markam
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 5:21 pm

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?    
 
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Stitch
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 5:24 pm

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]
 
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czbbflier
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:06 pm

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?
 
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ER757
Posts: 2506
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:16 pm

Quoting KarelXWB (Reply 32):

Agree - sounds like a QA issue at the manufacturer.....OK, putting on my flame suit in 3, 2, 1,   
 
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Stitch
Posts: 23453
Joined: Wed Jul 06, 2005 4:26 am

RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:17 pm

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]
 
mats01776
Posts: 131
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:25 pm

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.
 
AirbusA370
Posts: 51
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:46 pm

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)
 
Grisee08
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:49 pm

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.
You're Losing The Game!
 
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kanban
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:52 pm

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.
 
justloveplanes
Posts: 871
Joined: Thu Jul 08, 2004 5:38 am

RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:54 pm

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?
 
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par13del
Posts: 6720
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RE: ANA: Faulty Wiring On 787 Engine Fire Extinguishrs

Wed Aug 14, 2013 7:56 pm

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.

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