XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Apr 11, 2013 13:32:16 GMT 1
But that is enough to ensure the safety of the passengers. And that's the only thing the FAA is concerned about.
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Apr 11, 2013 13:53:25 GMT 1
But that is enough to ensure the safety of the passengers. And that's the only thing the FAA is concerned about. Difficult to prove it is a sufficient resolution, unless you can start a fire during a test flight. How much is a B787? Presumably Boeing/FAA are confident enough. Ignoring all this, it does come down to the fact that - is a commercial plane likely to receive initial certification with this problem? Would the FAA have signed off initial certification if Boeing admitted "we don't understand why, but this ought to fix it"? Possibly not
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Apr 11, 2013 13:58:33 GMT 1
Boeing destroyed a battery onboard ZA005 to demonstrate the new containment box.
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Apr 11, 2013 14:24:20 GMT 1
Boeing destroyed a battery onboard ZA005 to demonstrate the new containment box. Proving the fix doesn't actually prove the B787 design IMO
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harty236
Outfitting in Hamburg
Posts: 974
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Post by harty236 on Apr 11, 2013 20:52:04 GMT 1
Proving the fix doesn't actually prove the B787 design IMO Yeah, and wasn't there some issue with incorrect wiring as well?
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Apr 11, 2013 21:22:07 GMT 1
Boeing destroyed a battery onboard ZA005 to demonstrate the new containment box. Proving the fix doesn't actually prove the B787 design IMO Well, the 787 design can only prove itself when flying. Once the airframe is in service for - let's say 10 years - and had no fatalities, only then we can say it is a safe airframe (or not). Now back to the battery. We have to live with the fact that lithium-ion batteries can fail, and sometimes catch fire too. You cannot prevent that. In fact, ANA replaced 100 to 150 failed batteries before the fire events. A strong containment box should at least prevent the fire from spreading through the aircraft. The only proper solution would be switching to another battery type. But other types are bigger and will require Boeing to redesign the whole avionics bay due the limited space. That is too expensive, will cost too much time and therefore this will not happen.
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Apr 11, 2013 21:25:30 GMT 1
Proving the fix doesn't actually prove the B787 design IMO Yeah, and wasn't there some issue with incorrect wiring as well? As far as I know the incorrect wiring was installed by mechanics and has nothing to do with the design of the 787. Boeing can fix this by improving the quality control.
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Apr 12, 2013 0:45:35 GMT 1
Well, the 787 design can only prove itself when flying. Once the airframe is in service for - let's say 10 years - and had no fatalities, only then we can say it is a safe airframe (or not). Now back to the battery. We have to live with the fact that lithium-ion batteries can fail, and sometimes catch fire too. You cannot prevent that. In fact, ANA replaced 100 to 150 failed batteries before the fire events. A strong containment box should at least prevent the fire from spreading through the aircraft. The only proper solution would be switching to another battery type. But other types are bigger and will require Boeing to redesign the whole avionics bay due the limited space. That is too expensive, will cost too much time and therefore this will not happen. It's the "too expensive", "too much time" and the complacent "will not happen" that is the crux of this. (I don't mean to imply you are showing complacency, I refer to the situation) Taken to its logical conclusion, Safety Authorities would be faced with signing off planes purely because they are Boeing and Airbus. BTW, have Flight and Cabin crew representatives expressed any views? They would be under enormous pressure to fly the plane with a fire alert going on and reassure and calm passengers, while at the same time having concerns about their own safety. Safety or money first? The A350 is dealing with a change. The design is fixed although I realise the A350 has the time to incorporate the change before ISD. If the B787 avionics bay needs redesigning (which presumably the A350's doesn't), it's a problem which lays at the door of Boeing, and in itself does not justify relegating safety. Are any other International Safety Authorities going to give an opinion on this quick (well, relatively!) and dirty solution?
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Apr 14, 2013 16:14:43 GMT 1
I also prefer those batteries not failing in the first place. But we are not living in a perfect world and we have to deal with trade-offs between risk and cost. I cannot make it better than this.
If the containment box will prevent any fatalities than it is good enough. But if there will be a crash or fire due a failing battery than yes, the avionics bay will get a redesign to hold a new battery type.
I think that's a bit too hard. Back in 2007 the FAA was already concerned about the use of lithium-ion batteries in airplanes. Boeing had to proove it was safe to use those batteries (which was not, but nobody would have known this at the moment).
The "problem" is that the FAA is not as technical as the airplane mechanics themselves. So you have to send in the paperwork, the FAA will evaluate it and will decide if everything is ok. And sometimes they do some inspections. For example, in November 2011 the FAA found some incorrect installed wiring on JA804A - a few days before delivery - during a routine inspection.
Airbus can change the battery relatively easily because the A350 is still under development. To make the story better, Airbus development a "plan B" parallel to the A350 program in 2011 because they were concerned about the use of lithium-ion batteries. That's why they can swap battery types without delaying the EIS.
The avionics bay was designed very tight because weight savings were a key driver for the 787 program. It simply needs a redesign if you want to install larger parts.
Is that a design error? I don't know. I'm wondering if Boeing could have foreseen all these electrical issues. Nobody has a cristal boll after all.
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Apr 15, 2013 6:30:54 GMT 1
Time will tell if the cheap option is a sufficiently safe option. Personally I'd like to see Boeing held to account, but I will not disagree about practicalities, I just hope the FAA don't get their fingers burnt. Perhaps in hind-sight it would be useful to concentrate on new things which a design brings. You don't need a particularly sophisticated crystal ball to know that areas to concentrate on are the electrical system (more prevalent than before), new battery type and new construction materials. A design which has electrical fires on a test flight, requiring an emergency evacuation on landing, in my opinion needs a thorough check before being allowed to move further. I remain of the opinion that Boeing is too big and influential for the FAA to have any control over. Money talks
Anyway, I'd like to think we can agree to differ on points, while we both retain our beliefs that the B787 will be a safe design.
Is there any info on whether the FAA sign-off becomes an international sign-off? I don't know how these things work. Is the European Safety Agency responsible for international sign-off for Airbus?
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