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FAA Grounds 787s

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FAA Grounds 787s

Old 8th Mar 2013, 15:11
  #1181 (permalink)  
 
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I can't believe Boeing is dumb enough to fly a quick fix which only passes the FAA after more than the usual number of free lunches.

If that happens I hope the NTSB has the guts to say "this is not safe enough".
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Old 8th Mar 2013, 15:55
  #1182 (permalink)  
 
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Executive summary

It seems a pity that the executive summary did not finish four words earlier. Omit "lithium-ion battery system" (Is that 3 words or 4??) and we would have some real sense:

The NTSB is also continuing to review the design, certification, and
manufacturing processes for the 787.
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Old 8th Mar 2013, 16:05
  #1183 (permalink)  
 
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VAPilot 2004,

Aviation safety has moved on a lot since the 70's, while it's understandable to have teething problems when introducing new technology, both the carriers and their passengers did not sign up to become Beta testers.

Boeing's solution wouldn't have been acceptable in 1960 let alone 2013, the more you read the report the worse it gets.

Boeing didn't design the plane to have a battery fire in flight, I'm also damn certain that their calculations are way off on the battery swap frequency, if there's a problem with the battery, resolve the problem so it doesn't occur.


Putting the damn thing in it's own incinerator case and touting this as a workable solution is a triumph of the bean-counters over Boeing's illustrious heritage.
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Old 8th Mar 2013, 16:20
  #1184 (permalink)  
 
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Does anyone know if the Aft E&E bay is accessible from the cabin, i.e., in flight? From Page 8 of the report:
"This compartment is located aft of the main landing gear and beneath approximately the third set of cabin doors (L3 and R3). The compartment is only accessible from the ground by a door in the aft cargo compartment and a set of doors in the airplane belly."

The second sentence is ambiguous on this point. Is it "only accessible from the ground"? Or "from the ground (only accessible) by a door in the aft cargo compartment and a set of doors in the belly"?

And how about the Forward bay?
The aft EE bay is only accessible when the a/c is on the ground.

Either through a hatch in the belly (this is the normal maintenance route).

OR

Via the aft cargo hold through a door in the partition wall between the aft cargo hold and the EE bay.
Of course if the hold is full of pallets/cans etc that is a no go.

The fwd EE bay is accessed either through a hatch in the lower fwd fuselage or from the cabin through a hatch in the floor. Ergo, it can be accessed in flight.
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Old 8th Mar 2013, 16:22
  #1185 (permalink)  
 
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RAT

Quote from FlightpathOBN (after photo, Feb 28th):
"virtually ALL of the images of the 787 show the RAT deployed on ARR.."

My guess is that most of the photos will have been taken on acceptance flights. The RAT has to be tested, and it tends to be done towards the end of the flight, because of the buzz-saw noise (and maybe restrictions on other activities) once it is extended. That's what happens at Blagnac (Airbus).
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Old 8th Mar 2013, 16:25
  #1186 (permalink)  
 
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I have read this thread with great interest. A couple of thoughts:

It would be a very brave regulator that ignored the recommendations of the independent safety auditor. In the UK the CAA make great efforts in absolving themselves of any risk ownership and I can't imagine the FAA being any different.

I'm sure the battery problem will be solved one way or another. As others have said, the BIG question must be about the efficacy of the whole safety management process utilised in designing the aircraft. Boeing could be lucky and this event may be the only example of unsafe design, procurement or manufacture in the 787. On the other hand......
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Old 8th Mar 2013, 17:52
  #1187 (permalink)  
 
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Not so in the colonies

Cows:
It would be a very brave regulator that ignored the recommendations of the independent safety auditor. In the UK the CAA make great efforts in absolving themselves of any risk ownership and I can't imagine the FAA being any different.
In the US the NTSB makes recommendations. As an independent agency with its own body of expertise, the FAA sometimes does not follow them.

I'm sure someone will explain it better but I think the NTSB is decreed to be independent of improper outside influences and afaik does a good job of that. OTOH it seems to me that the FAA charter is not so saintly - its job is to keep airplanes flying safely, and not unlike other government agencies that touch on commercial interests it seems to have become more and more aligned with those interests over the decades.

This is the same body that, for instance, finds it difficult to mandate that our regional carriers hire well-trained pilots and pay them enough to assure they can afford a place to sleep at night and don't need a second job to raise their pay all the way up to our poverty level. I'll bet they're not having fun with this high-pressure situation - between a rock and a hard spot for them.
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Old 8th Mar 2013, 17:58
  #1188 (permalink)  
 
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The NTSB announced to set up a public enquiry/hearing about topics from NiCad batteries to certification. This will ruin any possible quiet agreement beforehand. Smart move by Hersman if you want.
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Old 8th Mar 2013, 18:29
  #1189 (permalink)  
 
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State of the main battery?

In their interim report, section 1.5.4, the NTSB reports having made Computed Tomography (CT) scans of both the APU battery that burnt, and "the main battery (that) was used as an exemplar battery for the radiographic studies". This sentence strike me:
The CT scans for the main battery showed no anomalies outside the cells.
And, in the "Ongoing and planned investigation activities, this one:
Document the results of the CT scans of the individual cells from the main battery.
Any interpretation of that?
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Old 8th Mar 2013, 18:39
  #1190 (permalink)  
 
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fgrieu:
Any interpretation of that?
To me, as I think to you, it suggests that they found what may be anomalies INSIDE the main battery cells.
Good catch!

Last edited by inetdog; 8th Mar 2013 at 18:39.
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Old 8th Mar 2013, 18:43
  #1191 (permalink)  
 
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@fgrieu

Document the results of the CT scans of the individual cells from the main battery.
The Root cause - of the Primary failure (cell short) - remains undetermined, without any tangible progress apparent.

The state of damaged batteries precludes determination of the Root cause.

To look for clues in other batteries (across the fleet) seems to be a good bet.
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Old 8th Mar 2013, 18:49
  #1192 (permalink)  
 
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Momoe:

Aviation safety has moved on a lot since the 70's, while it's understandable to have teething problems when introducing new technology, both the carriers and their passengers did not sign up to become Beta testers.
It has thankfully, yes. My point was the hullabaloo slowly died down and the new technology (then NiCad) moved forward. I don't think it will be any different today.

Boeing's solution wouldn't have been acceptable in 1960 let alone 2013, the more you read the report the worse it gets.
I too question the certification process. Nothing turned up. These two incidents are apparently a complete surprise to the cosmopolitan group involved - the Japanese battery manufacturer, the French electrical system integrator, Boeing, and both the American and European regulators.

Boeing didn't design the plane to have a battery fire in flight, I'm also damn certain that their calculations are way off on the battery swap frequency, if there's a problem with the battery, resolve the problem so it doesn't occur.
Truth be told, the battery's case and surrounding structure were designed with a possible overheat and fire in mind. This was mandated by the FAA. Boeing, actually Thales, France, paid an enormous amount of attention to the volatility and other dangers associated with lithium battery technology and it was thought all bases were covered. As it turns out, something got round their collective thinking.

Your point about the multiple swaps is a good one. It was not so much a longevity issue, it seems there were problems that nobody understood and since the electronics and computer wizardry were given a pass, the remaining troublemaker left standing was apparently assigned to a series of failed battery packs.

I feel fairly certain the problem surely resides within either the battery or the charging-monitoring system. What else is there?
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Old 8th Mar 2013, 19:23
  #1193 (permalink)  
 
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There are aspects of the electrical system that aren't working as they should, the battery swap frequency makes me think that the Li-Ion infrastructure needs to be better understood before a solution can be implemented.

Is the battery QC that bad? I don't think so. There are other factors at work here which need to be understood.
Only when the fault is replicated consistently will it demonstrate that these factors are understood, hopefully this will pave the way to a passive solution rather than the incinerator on board proposal.

I haven't forgotten the UPS 747F which went down in Dubai with Li-Ion batteries as the suspected cause, also the Asiana 747F which went down in similar circumstances. If these were passenger flights maybe Li-Ion batteries would be viewed differently.
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Old 8th Mar 2013, 21:43
  #1194 (permalink)  
 
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Momoe:
I haven't forgotten the UPS 747F which went down in Dubai with Li-Ion batteries as the suspected cause, also the Asiana 747F which went down in similar circumstances. If these were passenger flights maybe Li-Ion batteries would be viewed differently.
Not necessarily. These Li-Ion batteries were carefully placed in secure blue boxes and monitored, which *should* have eliminated the earlier problems. They might have been viewed differently by the public, but I am not persuaded that the engineers and regulators would have acted any differently.
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Old 9th Mar 2013, 00:07
  #1195 (permalink)  
 
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The frequency of failure surely must be an issue. Whilst the regulators might be prepared to accept the better containment solution, are the 787's customers really going to do so, especially long term? How many times are 787s going to land somewhere with smoke coming out of vents or battery fluid dripping down the side, how many ETOPS diverts with hot batteries, and (even if the battery pack is a LRU) how many times will 787s be AOG for lengthy periods because there isn't a spare battery pack at some outstation, before airlines say to Boeing - fix the problem properly?
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Old 9th Mar 2013, 00:26
  #1196 (permalink)  
 
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Mids, I don't see the FAA clearing this aircraft for passenger service with just a containment option on the table. There must surely be at least a likely cause identified for the meltdowns before it can fly.

As stated in an earlier post, there are two possible culprits in my mind. Something in the battery manufacture or some bit of missed trickery in the computer coding or electronics boxes provided by Thales.
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Old 9th Mar 2013, 01:51
  #1197 (permalink)  
 
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My guess is the software. It was probably written in C++. Computer code that crucial should be written in processor machine code. But maybe nobody knows that language anymore.

Last edited by kilomikedelta; 9th Mar 2013 at 01:55.
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Old 9th Mar 2013, 09:29
  #1198 (permalink)  
 
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APU Shutdown...

The fact that the APU shutdown because a battery had failed seems odd. The APU is there to generate power and was running... Clearly the expectation of battery failure was low in the engineer's mind when the systems were designed. Later on, in testing and certification, the same assumptions must have been made, or this undesireable behaviour would have been caught before.

Now that we know that these batteries can and have failed... it might be an idea to think about and test, what other system are effected by the batteries going off-line...
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Old 9th Mar 2013, 09:49
  #1199 (permalink)  
 
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Quentin,
it is not that uncommon for an APU to require a second source of power to run. This has been discussed in the other thread over at Tech-ops.

Even on the lowly DH8-300, switching off the main battery when running the APU (with no external power connected) would cause an instant APU shutdown.
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Old 9th Mar 2013, 10:41
  #1200 (permalink)  
 
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So its not a surprise.... Engineers have been designing systems, with the assumption that batteries are not going to fail. With the technology that we had... that was fine. Batteries didn't fail, so having a system that in this particular scenario, required the APU to run, to operate the vents, to control a fire... was fine.... because the battery wouldn't set on fire and go off line in the first place...

My point is that it is clearly not enough to simply insulate the batteries a little more and vent any fire out of the aircraft.... Thought has to be given to the implications of failure of batteries, that appears to have been a scenario not worth bothering about previously.
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