Can the APU be started in the case of fuel exhaustion? Is there a sump or "reserve tank" or something?

Walnut's post@51, prompted me to go back to #36 (TV programme posted by Jackx123)
I really wish I hadn't :suspect: If even 50% of that investigative journalism is true, then there's a massive amount of collusion and cover-up of which we are not aware. I had read an article elsewhere about the botched, substandard parts and assumed, like most would, "heck, they're still flying,Boeing always build like a brick outhouse,so even if the parts are a bit down on spec, there's still plenty of strength"
WRONG

Business and politics have been guiding the decisions in this matter......All the Engineering talent and informed opinion on this Forum, has a broad concensus that the 787 electrical system is fundamentally flawed,,,,,,yet it was certified safe and meeting regulatory requirements -until the evidence was overpowering and worldwide.

How the arrogant fools ever thought they could keep this hidden, I don't know. A bigger worry, is the extent of collusion by the very people who are supposed to keep the general public safe.

Bung them all on a faulty aircraft, show and explain the faults that THEY certified were safe, lock them in and fly them .....see how many have brown trousers and a new humility!

Fizz57.
No.

Edmundronald.
Very good points which I think were addressed in the Tech log thread. Fitting the APU with a dedicated PMG to power the APUC would seem the answer.

As for having no APU with a double engine failure. The Air Transat A330 into the Azores and the Gimli glider spring to mind.

APU battery
 

Kiskaloo

On B777 the APU battery can be removed with APU running as the controller receives power from the Main battery bus as well.
Strangely on B787 the APU controller has only the APU battery supply. Without that the APU shuts down.
I have no idea why this change. May be they wanted save the weight of a wire??

Dual power
 

Why all this complication of PMG. Make it like the B777, the APU controller receives power from Main Battery bus also. Keep it simple....

Hi tech.
As the reliability of both batteries is in question perhaps that is why.
Admittedly, the odds of both batteries failing at the same time...during an engine emergency...on an etops sector, are probably not worth calculating.

Some one will of course.

No ETOPS, no trips to Shemya Island?
 

ETOPS Not!
 

Until Boeing or the FAA can confirm the direct cause of the fire on either battery, the 787 should be Non ETOPS
The only way to even look at ETOPS would be a design change back to Nicad batteries and re-certification with the Nicads as part of the electrical system for the Main & Apu Batteries.
Until then, the rubbish fix which doesnt confirm the original cause of the fault, should result in the 787 staying Non ETOPS.
The Dreamliner has become the Nightmare Liner...a 78 Lemon!

Was sent this yesterday. :O

http://i82.photobucket.com/albums/j2...ps8c9de1ad.jpg

I don't think it's even possible due to space requirements to go nicad. The equivalent nicad batteries would be far larger than the li-ion ones.

I would not be surprised if the JTSB temporarily rescinds their approval to allow NH and JL to operate the 787 at ETOPS-180 and the FAA may again decide to follow their lead for PR purposes as they did with the grounding.

On the other hand, considering the 787's testing was trouble-free enough for the FAA and EASA to find the 787 suitable for ETOPS-180 operations and the plane flew without incident for over a year, which convinced the JTSB that the 787 was suitable for ETOPS-180, to issue a new ruling that finds the 787 not suitable for ETOPS-180 operation might call into question again how these agencies certify twin-engined aircraft for ETOPS at EIS and that could impact the suitability for ETOPS at EIS for new twins like the A320neo, A350 and 737 MAX.

Pretty straight forward really - they made a determination based on the evidence and granted approval. Subsequent events raised significant concerns about the capability, those events were not in evidence at the time the original determination was made.

Accordingly the evidence was reviewed and a new position, based on the additional evidence determined.

Does it call into question how certification works?

Almost certainly not. A test and compliance regime would be determined and certification granted if passed. If subsequent events mean a type no longer passes then their accreditation is reviewed.

Sounds like a sensible pragmatic process. Where's the problem? The battery fire? Sure that's bad, but if it didn't happen in testing then there's no reason to fail the accreditation process. And if subsequent events contradict the genuinely obtained results during certification then you review what certifications are granted.

How is any of this hard to understand? Things can change and the system is flexible enough to cope with that.

In three hours, the battery box would probably be down to ambient temperature, or darned near it. There's only so much stored electrical energy and electrolyte in the battery, think self extinguish. You really can't "fight" a Lithium battery fire, just safely contain it until it's out. The new vented containment system should address the fire risk very well.
Pete

Since you can fly the 787 without an APU battery or APU, we're honestly saying that because one Ship's Battery failed in flight we should therefore determine the 787 is no longer suitable for ETOPS-180?

Should we find the 767, 777 and A330 not suitable for ETOPS-180 every time one of them suffers an inflight shutdown of an engine?

Should we risk finding the A350 suitable for ETOPS-180 before EIS? Or should it suffer an IFSD or some other ETOPS-related systems failure, should we immediately find it unsuitable?

I don't think the batterymalfunction is the root cause the FAA is reconsidering; it merely wakens them up that they have certified a brand new aircraft to ETOPS right from the start, without it proving itself in line flying. First fix the teething problems (or prove that there aren't any), then let it become ETOPS

golfyankeesierra
They certified the 777 as suitable for ETOPS-180 before the first revenue flight took off from Dulles for Heathrow.

And it's assumed EASA will certify the A350 as suitable for ETOPS-180 before the first revenue flight departs Doha, so should the FAA break tradition and not accept EASA's certification suitability until the A350 accumulates sufficient flight hours to "prove itself"?

And we should remember that the 787 did fly for over a year without major incident, so how long is long enough when it comes to proving oneself with flying? For the Japanese, it was a year, and once the 787 met that requirement, they allowed NH and JL to operate it on missions with ETOPS-180.

It seems extra ordinairy meassures were taken by Boeing and the airlines to keep 787 dispatch reliability up, which is different from aircraft reliability. Even 100+ battery exchanges didn't ring a bell. The FAA is reviewing all. The question is in how far they are covering their .ss and how much the truth about 787 is becoming clear.

How Airlines Kept 787s on Schedule - WSJ.com