FAA Grounds 787s

[SMT Member]

Seems to me that, given the lack of a root cause and Boeing being in a rush to get the aircraft back flying, the proposal submitted utterly fails to address the real problem and is focusing on containment only. In other words, they're not going to fix the root cause.

Don't know about you, but that doesn't wash with me, and I hope the FAA will tell them to bugger off back to the drawing board and design a battery system that's no more liable to combustion then NiCad's.

[toffeez]

Extracts from the FAA 787 Special Conditions

"As a result of this extensive use of a new construction material,
the fuselage cannot be assumed to have the fire resistance previously
afforded by aluminum during the in-flight fire scenario mentioned
above. These special conditions require that the 787 provide the same
level of in-flight survivability as a conventional aluminum fuselage
airplane."

"We agree that the heat transfer characteristics of
aluminum influence its response to an in-flight fire, and that a
composite structure will doubtless behave differently. The goal of
these special conditions is to enable continued safe flight and landing
in the event of an in-flight fire that directly impinges on the
fuselage structure."

I bet nobody was then considering the effect of a red hot steel box transmitting heat to the composite structure for up to 180 minutes.
.

[green granite]

The question is of course, would you pilots be prepared to fly it with Boeing's 'fix'? I would avoid it as a passenger, as I did the DC10.

[Ex Cargo Clown]

Can't just be a weight problem, if you can stick it in a Ti box you can put a NiCd in. More than this than meets the eye, must be a load issue.

Whose going to fly on an aircraft which may or may not potentially be on fire?

[HalloweenJack]

Can i ask a question regarding stuffing these things into a box? Will it be covered completely minimising the fire risk? And if what i`ve read on here is true , if thats the case ; surely the self sustaining properties would in fact make a fire hotter in an enclosed space? Thus giving it an increased risk?

[Machinbird]

Can't just be a weight problem, if you can stick it in a Ti box you can put a NiCd in. More than this than meets the eye, must be a load issue.

You do know that Ti can burn under sufficiently intense conditions?

Whose going to fly on an aircraft which may or may not potentially be on fire?

The fact that a battery is locked inside a box is just part of the design change proposed.

The heat energy is not bottled in the box heating it to some gosh awful temperature, it is vented to the outside of the aircraft thus limiting the heat buildup inside the aircraft. From an engineering standpoint, complete battery runaway is a containable event. You folks fly with your engines on fire (internally) all the time, and the only time you get excited is when the fire unexpectedly goes out.

Give the engineers a little bit of credit for being able to mitigate a problem when their attention is focused on it.

[syseng68k]

green granite:

I'm sure it will be a great aircraft, and I would fly in it, but with the proviso that if
Boeing are starting to go the way of companies like Microsoft, where the last
stage of development is done by the punters, I would wait a few years and at least
service pack 3 before getting on board.

Never pays to be an early adopter, let them shake all the bugs out first ...

[Momoe]

Give the engineers a little bit of credit for being able to mitigate a problem when their attention is focused on it.

I have issues with that statement at many levels:

First, are these the same engineers who designed the Lithium-Ion battery system (and oversaw the whole design/implementation/testing process) in the first place?

Two, definition of mitigate is to "Make less severe". Any fire (other than the engines), is a no-no on any aircraft, period. I'm not interested in a fire being made less severe, I am however very interested in not having it happen in the first place.

Three, if building an incinerator box for the batteries, albeit a vented one is what these engineers come up with when their attention is focused, I for one am not impressed.

IMO, this is a patch, it's the quickest means possible of getting the planes flying again - beancounter engineering.

[Smilin_Ed]

This Pilot Will Not

The question is of course, would you pilots be prepared to fly it with Boeing's 'fix'? I would avoid it as a passenger, as I did the DC10.

This pilot will not get in a 787 until they completely change the battery chemistry.

[toffeez]

This should not be a consideration for Boeing, but ... it would be somewhat embarassing if Airbus gets the A350 in the air when the 787 is still grounded.
That gives them about four months.

[EEngr]

Momoe

First, are these the same engineers who designed the Lithium-Ion battery system (and oversaw the whole design/implementation/testing process) in the first place?

No, and yes (more or less).

The design and manufacturing of the various components of the battery systems were outsourced. So the "put it in a fireproof box" fix is Boeing's way of mitigating someone else's design error.

Three, if building an incinerator box for the batteries, albeit a vented one is what these engineers come up with when their attention is focused, I for one am not impressed.

I'm impressed by the fact that the few remaining engineers at Boeing haven't just jumped ship and gone to work for the local power company. With management breathing down their necks and a decade or so of neglect for properly staffed and funded design, testing and analysis capabilities in house, this is about what I'd expect.

I'm just waiting to see if the firebox solution, once signed off by the FAA, doesn't become the long term fix. Following management pulling the budget for solving this problem.

I'm waiting to hear what the final root cause and solution will be. But I'm afraid we may never know. Because no one will continue looking. If they did, the next step would be to retrofit a fix to the fleet. This means millions of dollars more in parts, labor and aircraft down time. The alternative is to fund some poor slob poking around in the lab. With "no solution yet" as an answer.

[Momoe]

Outsourced or not, the buck stops with Boeing.

This is a tough challenge for Boeing, the outsourcing model failed, a lot of folk are looking to Boeing to come up with an elegant, engineered solution that is a rubber-stamp job for the FAA; The current proposal is a crock.

Don't do this - No-one wants one manufacturer to have the monopoly on large passenger aircraft, cons outweigh the pro's.

[WilyB]

I bet nobody was then considering the effect of a red hot steel box transmitting heat to the composite structure for up to 180 minutes.

Or venting heat and flames outside while they are refueling the 787.

[WanganuiLad]

"....I bet nobody was then considering the effect of a red hot steel box transmitting heat to the composite structure for up to 180 minutes...."

Maybe they could run a wetback from it to the galley califont
Earn carbon credits

[Spooky 2]

Boeing briefing

Take it for what it's worth and don't know the original intened audiance.

International Video Player (resizable)

[Mk 1]

WilyB, You cannot be serious asking this question:

Or venting heat and flames outside while they are refueling the 787.

if you knew there was an under bonnet fire in your car as you pulled into the service station, would you attempt to refuel your car?

Give airline staff and airport refuellers a little credit for intelligence.

Besides the presence of a stack of big lime green fire units would probably mean that even the most stupid refueller probably couldn't get close enough anyway.

Wily - you seem to misunderstand the situation here. The 787 after receiving this mod will not be flying around the skies totally oblivious to the little lithium furnace burning merrily away trailing smoke like an old 707 over a period of months. In the rare even of this happening again BEFORE a more permanent fix is found, the box and venting are designed to mitigate collateral damage whilst the crew seek out the nearest safe airport so the emergency services can extinguish the blaze.

[Ex Cargo Clown]

You do know that Ti can burn under sufficiently intense conditions?

I'm more than aware of that most will get a bit"flimsy" at around 420 degrees. What's worse though is the alloys have lovely stuff like molybdenum in them, which I wouldn't be sprinkling on my cornflakes.

[syseng68k]

Melting point of Titanium is around 1700 C, not that much different from Stainless
Steel and it would probably take much more to make it burn, though no metallurgist.

Fwir, steel heated to 1000 C looks almost white hot...

[Ex Cargo Clown]

Deforms at 420 degrees, trust me.

[inetdog]

Standing behind my usual claim of ignorance, I'd guess that NiCd would be fine in the APU-battery role, and it's lithium just to keep the LRU count down. The real requirements for the two batteries must be hugely different.

The official explanation is that the Li battery can deliver enough power for several starts of the APU and then be quickly recharged again once the APU or other power source is running. NiCd's higher internal resistance makes very rapid recharging more problematic.
Using the same battery for both purposes is a little harder to justify, but in terms of design, testing and acceptance seems plausible.