Boeing 787 faces new risk: limits on ETOPS

[keesje]

Reuters has this article on possible ETOPS consequences of FAA findings. In the past aircraft needed a good reliability record to apply for longer ETOPS.

(Reuters)
As Boeing works to regain permission for its 787 Dreamliner to resume flights, the company faces what could be a costly new challenge: a temporary ban on some of the long-distance, trans-ocean journeys that the jet was intended to fly.

Aviation experts and government officials say the Federal Aviation Administration may shorten the permitted flying time of the 787 on certain routes when it approves a revamped battery system.
Boeing 787 faces new risk: limits on extended range: sources | Reuters (http://www.reuters.com/article/2013/03/27/us-boeing-787-range-idUSBRE92Q00920130327)

Not so long ago Boeing was working towards 787 ETOPS330. Boeing nears 787 GEnx and 330min ETOPS certification (http://www.flightglobal.com/news/articles/boeing-nears-787-genx-and-330min-etops-certification-369474/)

For illustration I generated an indicative ETOPS90 chart from Great Circle Mapper (http://www.gcmap.com/). I have no idea what limitation the FAA would apply, if at all, for the 787 to re-enter service.
http://www.gcmap.com/map?P=LAX-NRT,+ATL-CDG,+HKG-LHR,+SYD-SFO,+SIN-JNB,RIO-FRA&E=90&MS=wls&MR=1800&MX=720x360&PM=*

[Takeoff53]

ETOPS 90 looks hard but ETOPS 120 might be ok for a while as most routes would be possible(?), except the Pacific.

[Kerosene Kraut]

Transpac would be it's main market by the way.

[FlightlessParrot]

From a New Zealand perspective, this is of course a BFD. But how bad a hit would it be for routes between, say, USA and northern Pacific Rim countries?

[keesje]

From a New Zealand perspective, this is of course a BFD.

Downunder-USA would be an issue..

http://i191.photobucket.com/albums/z160/keesje_pics/ETOPS120Pacific_zpsb74c6645.jpg

I guess QF and ANZ hoped for ETOPS 240 at least.

QF now has -9 options only, ANZ is committed.

[Fly747]

Well I wouldn't want to go very far from an alternate in the thing until it has got a few trouble free miles under its belt.

[Kiskaloo]

There is no regulatory basis to reduce the 787's current ETOPS-180 certification as that allows for a flight to depart with an inoperative APU battery or APU.

So if regulators are going to assume that the APU battery is still likely to fail and inop the APU, that would still allow ETOPS-180.

[keesje]

There is no regulatory basis to reduce the 787's current ETOPS-180 certification as that allows for a flight to depart with an inoperative APU battery or APU.

Was the battery operative during the JAL platform incident?

Is the battery charged during flight?

[lomapaseo]

Was the battery operative during the JAL platform incident?



Only if you leave it on.

[TURIN]

There is no regulatory basis to reduce the 787's current ETOPS-180 certification as that allows for a flight to depart with an inoperative APU battery or APU.

So if regulators are going to assume that the APU battery is still likely to fail and inop the APU, that would still allow ETOPS-180.

What about the main battery failing?

AFAIK there is no MEL item for dispatch with a main battery inop. :eek:

[WHBM]

There is no regulatory basis to reduce the 787's current ETOPS-180 certification as that allows for a flight to depart with an inoperative APU battery or APU.

So if regulators are going to assume that the APU battery is still likely to fail and inop the APU, that would still allow ETOPS-180.
I understand that you are from Seattle and keen to bat for the home team, but even there it is surely understood that the recent issues with the battery were not due to it being inoperative - the thing caught FIRE !!!

[Annex14]

Probably that recently published addition by AvHerald tells a bit more about facts and reasons

On Mar 27th 2013 the JTSB released another interim report in Japanese (http://www.mlit.go.jp/jtsb/flash/JA804A_130116-130327.pdf) summarizing, that a "smoking gun" has still not been identified, the investigation so far has not yet led to "elucidation of the underlying cause". The JTSB reported that the puzzle about the navigation strobe lights has been solved however (see sketch below), with both APU and main batteries showing balanced voltages neither relay would be powered with the related switches off, however, with the main battery's voltage dropping to 1V a current flow from the APU battery via both relays to ground became possible, both relays activated and the wing tip and strobe lights activated despite being switched off. The wire connecting the battery case to ground was broken and showed evidence of having been blown (editorial note: implicitely suggesting prior to the battery event), however, the aircraft had no history of a lightning strike. There is no evidence, that battery charger, bus power control unit, generator control unit or battery diode module did not perform to specifications. Battery cells 1-8, especially 3 and 6, showed extensive internal damage, there is evidence that a large current flow occurred on the output of the battery towards the hot battery bus.

The bold letters is my addition.
Was quoted repeatedly in the other B787 thread, if a lithium battery is discharged to such a level, no re-charging should occur ! Wether it happened in these cases under investigation is not yet clear. But it should also be clear it´s not only the APU battery that is in jeopardy, the ANA case was the main back up battery.
Regardless what those Boeing PR people release to the public, as long as the real cause is not found the whole set up is not safe. So no release to normal ops should be allowed.

[RobertS975]

The ETOPS time doesn't matter if your airplane is burning! SR111 couldn't stay in the air for 35 minutes after the cockpit crew reported smoke. AC 797 had a lavatory fire over the heartland of the USA and couldn't land in time to avoid mass casualties.

[Christophglex]

at what single engine speed was that map created?

[EEngr]

RobertS975 (http://www.pprune.org/members/50934-roberts975):

The ETOPS time doesn't matter if your airplane is burning!That's the point of the metal box.

Look at it this way: Without the box, a battery fire is a critical safety issue. Because it has the potential for bringing down the plane, it must be extremely improbable (< 10E-9 per flight hour). Since it appears that this is not the case, we get the fireproof box. The sales pitch for the box doesn't appear to have a time limit for withstanding a fire (at least none that I've heard). So that means diversion range in the event of a fire will be based on the remaining system capabilities. If you had ETOPS-180 before the battery caught fire, you still have it. That's the position we will be in if the FAA buys the battery in a box solution.

[Kiskaloo]

TURIN
What about the main battery failing?

AFAIK there is no MEL item for dispatch with a main battery inop.

If the engines and APU are dead and you are fortunate enough to make it to a runway, the Ship's Battery job is to power the brakes. And if you, and your Ship's Battery is dead, then you're probably going to have a runway overrun. But at least you'll have emergency equipment present and CFRP is strong.


WHBM
I understand that you are from Seattle and keen to bat for the home team, but even there it is surely understood that the recent issues with the battery were not due to it being inoperative - the thing caught FIRE !!!

And I understand that being from the UK, you must love all things Airbus since they design and build the wings for their commercial airplane families there. :rolleyes:

Yes, the cabling caught fire on JA829J. And in response, Boeing has switched to cabling that is far more resistant to fire and is capable of withstanding significantly higher temperatures (many hundreds of degrees Centigrade).

They've also encased the battery in a fireproof titanium container and shown that there is insufficient oxygen present within to sustain combustion for a few thousandths of a second even with thermal runaway and electrolyte leakage.

[kaikohe76]

As a matter of interest, can someone please confirm the current limit on the B777 thanks. Just wonder, if very unfortunately the 787 saga lingers on & with operating restrictions as well, could more 777s fill the gap?

Cheers

[zlin77]

777 ETOPS limit is normally 180 mins....however in a previous Airline we had approval to go to 207 mins...From what I remember we had to have a serviceable APU for 207 mins......Distance is normally determined by the airline with regulatory approval...current operation is 1293 nm S/E still air.

[toffeez]

Indeed, and once on the ground you'll have the comfort of knowing that the polar bears won't attack a blazing 787.
.

[matkat]

Kiskaloo, are you sure that you can dispatch an ETOPS flight with the APU inop? if so it's the first I have heard of any aircraft being allowed to do this indeed in my experience we had to have an ETOPS compliant APU which in essence meant that it had to be able to start in flight even having been cold soaked.
You also mention above about the main battery powering the brakes am I to take that the B787 does not have a RAT?

[SloppyJoe]

A330 can dispatch for an ETOPS flight with the APU INOP. Emergency generator powered by hydraulics is an alternative power source.

[whatdoesthisbuttondo]

The 787 can dispatch and operate 180 minutes ETOPS with the APU battery inop or even removed, as long as the Variable Frequency Starter Generator is working.

The same restriction applies to the APU itself. You can operate 180 minutes ETOPS with it inop or removed, (as long as the VFSG works).

[Kiskaloo]

kaikohe76
as a matter of interest, can someone please confirm the current limit on the B777 thanks. Just wonder, if very unfortunately the 787 saga lingers on & with operating restrictions as well, could more 777s fill the gap?

As of December 2011, the 777 is now certified for ETOPS-330 (http://boeing.mediaroom.com/index.php?s=43&item=2070).

Air New Zealand 777s use ETOPS-240 for their Aukland-Los Angeles route.

[denachtenmai]

kiskaloo
And I understand that being from the UK, you must love all things Airbus since they design and build the wings for their commercial airplane families there.

You are trying to bring this discussion into a battle between Airbus and Boeing by your comment.
I have done longhaul on A330's and 767's with no inclination to favour either, but,and it's a big but, I have no intention of stepping onboard a 787 until the cause of the battery problem has been rectified, not the lashup that Boeing is presenting as a "fix".

[Pub User]

matkat

You also mention above about the main battery powering the brakes am I to take that the B787 does not have a RAT?

It does have a RAT, but it wouldn't provide enough power to operate the brakes at landing speeds, so the battery is the backup.

[whatdoesthisbuttondo]

As above, the main battery is only the backup source for electric brakes. The normal source of brakes is the 28VDC.

The main battery provides power for:
• airplane power-up
• APU start (assists APU battery)
• refueling operations
• towing operations
• electric braking (as backup power source)
• captain’s flight instruments (energizes essential instruments until RAT
deployment)


The APU battery provides power on the ground for:
• APU start
• navigation lights (during battery-only towing operations)

Clearly the 787 isn't short of electric power sources. There are . . .

• four variable frequency engine starter/generators
• two variable frequency APU starter/generators
• three external AC power receptacles
• one Ram Air Turbine (RAT)
• one main battery
• one APU battery
• three flight control Permanent Magnet Generators
• two EEC Permanent Magnet Alternators

[eppy]

Clearly the 787 isn't short of electric power sources. There are . . .

• four variable frequency engine starter/generators
• two variable frequency APU starter/generators
• three external AC power receptacles
• one Ram Air Turbine (RAT)
• one main battery
• one APU battery
• three flight control Permanent Magnet Generators
• two EEC Permanent Magnet Alternators

All the other power supplies able to supply enough power for braking require a fuel powered generator when when in flight (Engine Generators or APU). The scenario that others have referred to is the "Gimli Glider" where an aircraft ran out of fuel and glided in for a deadstick landing.

My understanding is that many believe that the RAT won't be able to provide enough power for braking as the aircraft slows upon landing (note: I haven't seen this assumption confirmed or denied by Boeing).

So the question is: Will the FAA/JTSB, etc accept the statistical probability being execeedingly low that a 787 would not run out of fuel and lose a battery on the same flight, and therefore have no wheel braking?

[Pub User]

So the question is: Will the FAA/JTSB, etc accept the statistical probability being execeedingly low that a 787 would not run out of fuel and lose a battery on the same flight, and therefore have no wheel braking?

I would think, statistically,

run out of fuel

would be enough of an improbability that the FAA would not even have to consider it, even if the battery failed on EVERY flight.

[Pub User]

My understanding is that many believe that the RAT won't be able to provide enough power for braking as the aircraft slows upon landing (note: I haven't seen this assumption confirmed or denied by Boeing).

Whatever 'many believe', the Boeing manuals tells us this:

The main battery provides power for:
• airplane power-up
• APU start (assists APU battery)
• refueling operations
• towing operations
• electric braking (as backup power source)
• captain’s flight instruments (energizes essential instruments until RAT deployment)

In-Air Rat Only mode is active if loss of all electrical power to captain’s and first
officer’s flight instruments occurs in flight. The RAT energizes the captain’s flight
instruments and other essential equipment for flight controls, navigation, and
communication. The main battery provides standby power until RAT deployment.

There is no mention, in the entire manual, of the RAT having any effect on the wheelbrakes.

[Cool Guys]

Pub User & whatdoesthisbuttondo

Its good to read some good technical facts. I am curious:

1. What drives the three flight control Permanent Magnet Generators and the two EEC Permanent Magnet Alternators.

2. What happens to the captain’s flight instruments etc if the main battery fails to provide standby power until the RAT deploys.

[whatdoesthisbuttondo]

As For the Ram Air Turbine (RAT)

A Ram Air Turbine (RAT) serves as an emergency source of electrical and
hydraulic power. It has no operating time limits, airspeeds, or altitudes.

Nothing to suggest it won't power the brakes on the ground if the battery isn't working AND then somehow the aircraft is then run out of fuel. (I think someone asked about this highly unlikely scenario)

Hi Cool Guys,

Apologies for answering your question by click and pasting,

Permanent Magnet Generators

Three engine driven Permanent Magnet Generators (PMG) are the primary source
of power for the flight control electronics. These power sources are independent
from the main airplane electrical system, and are also independent from each
other.
A secondary source for flight control power is provided by the airplane’s 28 Vdc
bus distribution system, and the main battery. In addition, a backup system is
provided by dedicated batteries to assure positive flight control operation during
temporary power interruptions.

Permanent Magnet Alternators

Two engine driven Permanent Magnet Alternators (PMA) (one per engine) are the
primary source of power for the EEC. PMAs are independent from the main
airplane electrical system, and are also independent from each other.
A secondary source for EEC power is provided by the airplane’s 115v AC bus
distribution system. During engine start, initial EEC power is provided by the
airplane until the PMA is able to provide power. The airplane also serves as a
backup EEC power source if a PMA is inoperative.

So engine driven is the short answer. Like most aircraft, the methods of producing electrical power are Ground external, APU, Engine and Batteries and RAT.

As for you second question about flight instruments if there were no battery and then the RAT deployed? Remember the RAT is only required if

• both engines have failed (and in your scenario there wasn't an APU battery available to start the APU or fuel to run it)

• loss of all electrical power to captain’s and first officer’s flight
instruments

In this (again) extremely unlikely example, I expect there might be a short power interruption until the RAT came online. That would be seconds rather than minutes though.

[eppy]

A Ram Air Turbine (RAT) serves as an emergency source of electrical and hydraulic power. It has no operating time limits, airspeeds, or altitudes.

According to this link (Question 6): https://cramberry.net/sets/63118-757-hydraulics (http://https://cramberry.net/sets/63118-757-hydraulics) the RAT on a 757/767 requires a minimum airspeed of 130 knots. I don't know what the limit is for the 787, but it is clear that this equipment is designed and certified to provide emergency power in the air, not for electrical braking on a landing roll.

To claim that it has no operating airspeed limits would logically imply that that it could produce sufficient power if it was deployed while the aircraft was being towed. That would solve the battery rundown while being towed problem - just deploy the RAT and the aircraft will power itself! :ugh:

[Cool Guys]

whatdoesthisbuttondo,

Thks for the reply. The 787 sure has a few power sources.

Just ignore eppy's little head banging exercise. I am sure everyone else understands you did not mean the RAT could be employed while towing

[cockney steve]

everyone else understands you did not mean the RAT could be employed while towing

Yes! We do!....But the "Boeing Bullcrap" implies that the RAT will be the saviour IF all other power-sources fail.
This clearly isn't the case.

Main engines each drive 3 gennies (2 starter-generators, 1 alternator)

but, hold on, there are 3 alternators, 1 to each engine:confused:

Smell the bull**** yet???

APU drives 2 starter-gennies.
RAT= a glorified windmill-generator..... as such, it's SPEED-DEPENDANT

Basic physics, it turns apparent wind into electrical energy
Irrespective of fuel-levels ,a "dead-engine" scenario is VERY possible

Remember the "over the fence" BA Heathrow flight???
Plenty of fuel, but it didn't turn and burn...that was a "Tin" 'plane, with years of development and Empirical knowledge behind it.

Now we have a Plastic Fantastic and a whole lot of new issues to learn.

SO, We lose both engines in flight.....the batteries are U/s (but that's OK) RAT is deployed, but can't start the APU (making the sweeping assumption that it has enough capacity to start it)

Heroic aircrew plonk it on the ground into the teeth of a 120mph gale!....all our problems are solved....headwind reduces groundspeed and also powers the RAT so the brakes work.

IN real life, As airspeed drops, so will the RAT's output...that presents a real problem, as the likelihood of both batteries failing is currently , statistically very high....2 holes in the cheese are ALREADY lined-up.

[RCav8or]

"Remember the "over the fence" BA Heathrow flight???
Plenty of fuel, but it didn't turn and burn...that was a "Tin" 'plane, with years of development and Empirical knowledge behind it."
Yes, but even as a lowly SLF. I also understand that the engines, while unable to provide the required thrust, were still producing adequate electrical power. They were turnin and burnin, just not quite fast enough! As I understand, even Capt. Sully's A320, with both engines damaged and not producing usable thrust, the engine generators were still producing electrical power and the A320 remained in normal law until splashdown.

[jackx123]

problems with Boeing 737 next generation with structural dangers reported on sbs datline australia - YouTube

[whatdoesthisbuttondo]

Cockney steve.

"Irrespective of fuel-levels ,a "dead-engine" scenario is VERY possible

. . . . . . And later . . . . .

IN real life, As airspeed drops, so will the RAT's output...that presents a real problem, as the likelihood of both batteries failing is currently , statistically very high....2 holes in the cheese are ALREADY lined-up."

I don't agree with you that a double engine failure is "VERY possible", it is an extremely rare event. Especially one where a restart isn't possible. Also to say the likelyhood of both batteries failing is "statistically very high" is also simply untrue.

The 787 has had two individual battery incidents. I'm not sure how you decide a double engine failure or a double battery failure are at all likely. It's a bit sensationalist to suggest you think the aircraft might suffer a double engine failure and a double battery or even single battery failure on the same flight. You also don't know what speed the RAT will provide electric braking down to. I don't know why you're contradicting the Boeing statements about the RAT when you don't seem to have any relevant technical knowledge of it whatsoever.

The same kind of tiny probability leading to a double engine failure and then an unrelated failure of another crucial system would leave most aircraft in a very poor state to land and stop on a runway. A similar example might be a 757/767 suffering a double engine failure followed by a double hydraulic failure. Sure it's possible but let's not pretend its likely or some kind of design fault.

[TURIN]

Perhaps but it will still have an accumulator full of 1800psi nitrogen and hydraulic pressure to power the emergency brakes. Somerhing a 787 wont have

[whatdoesthisbuttondo]

Right but the 787 has engine generators, batteries, an APU and a RAT. Do you really think its likely, it will suffer a combination of failures that would leave it unable to stop on a runway?

[UniFoxOs]

As I understand, even Capt. Sully's A320, with both engines damaged and not producing usable thrust, the engine generators were still producing electrical power

As I understand it he started the APU.

[deptrai]

UniFoxOs is right - they had the incredible presence of mind to immediately start the APU.

But even if there had been any power coming from the heavily damaged engines...the relight procedure (which they followed if I remember correctly) will require to set the engine master switch to off for some time, to permit ventilation of the combustion chamber, after an unsuccessful attempt - at that point there definitely can't be any generator power whatsoever.

[cockney steve]

My last post, (as some will have realised) ;) was deliberately over-dramatised.

The batteries areonly as good as their reliability and state of charge,

To pretend to oneself that they meet their functional requirements, is tobe in denial.. they have caused 50 aircraft to be grounded and god knows how many completed airframes to back-up at the factory out-door.

there have been at least 2 out-of fuel instances, plus the BA incident, plus the "Sully" incident, that i can recall in my lifetime. in commercial Pax-carrying Aviation.

Composite -structures have totally different Thermal properties to Aluminium Alloys... to have blind faith in a bunch of feckwits who designed wings that wouldn't fit. a faulty electrical system that can backfeed and flatten the second battery (if neither becomes incendiary in the interim!)...is naive in the extreme.
IMHO, they haven't had enough operating experience to really know if fuel-freezing /starvation will ever be an issue.
Prudence suggests one plans for a worst-case scenario and the multiple-backups are/ should be predicated on this
IF both main-engines fail to produce enough power (for whatever reason)
It's all in the lap of an unsafe, unreliable battery-system to start the APU
As it stands, that can't be assured, so I stand by my assertion that 2 holes line up. It cannot be denied there is a safety-critical weak link in the design...the American authorities themselves decided that grounding was more important than national pride.

As a matter of National Pride, the US Government will make sure Boeing survive this crisis...but it won't be due to the expertise of the current management of the company.

[Pub User]

Yes! We do!....But the "Boeing Bullcrap" implies that the RAT will be the saviour IF all other power-sources fail.

Boeing neither state nor imply that the brakes are served by the RAT.

[whatdoesthisbuttondo]

"It's all in the lap of an unsafe, unreliable battery-system to start the APU"

I assume you've followed the changes made to the batteries?

Before the aircraft has actually been cleared (or not) to fly, you've already decided the new proposed solution is unreliable and unsafe?

How do you know it's unsafe?

[TURIN]

Whatsthisbuttondo.
Its a regulation requirement to have an independent backup brakes source.
On a hydraulic dependent a/c the RAT will not supply enough energy to supply the brakes. Whether it has a hydraulic pump or a generator driving a pump etc.
The 787 requires an independent backup power source for its braking system. The battery is it.
It matters not a jot whether you or I calculate the odds of it being needed as 10 milllion to 1 or evens.
The regs say it needs to be there. End of.

[whatdoesthisbuttondo]

"The 787 requires an independent backup power source for its braking system. The battery is it.
It matters not a jot whether you or I calculate the odds of it being needed as 10 milllion to 1 or evens.
The regs say it needs to be there. End of."

Yet the "regs" (the MEL) allow a 787 to dispatch without a functioning battery?

[Pub User]

No, the MEL allows dispatch without a functioning APU battery; it's the main battery that supplies back-up power to the brakes.

[Takeoff53]

Just to be curious: Is there an APU existing, which can be started by windmilling?

[whatdoesthisbuttondo]

The point is, if the 787 gets cleared to operated again, it will be because the FAA/NTSB/whoever decide the battery solution is safe and reliable enough.

Thus the main battery will be the back up to the brakes. Why are people suggesting or assuming the 787 will be flying around without a battery or in a perilous condition as there might be a double engine failure, then for some reason the APU won't start and THEN the (new safer more reliable) main battery will also fail?

The 787 when cleared to fly will have a backup source for the brakes as the new battery and it's associated systems will have been certified as being safe and reliable. As I ever, I expect some people have ulterior motives to scare monger but there seems to be a lot of unfounded sensationalism on this thread.

[Walnut]

I have just looked at the Jackx 123 (posting 36) which I find very disturbing. I suggest all to give it a look. Cutting edge technology always has risks but not to learn, follow up & fix problems is unforgivable.
The 787 is cutting edge in so many ways. But I now feel that there have been so many other safety issues (not just the batteries) that the general airworthyness needs to be looked at carefully.

[Chu Chu]

If we're still talking ETOPS, it seems to me that anything that might or might not happen after both engines fail is pretty much irrelevant . . .

[Momoe]

Perrin,

Going to call you on your statement "No manufacturer will ever ask you guys to fly in in a unsafe A/C if they knew it had a fault."

Turkish DC-10 1974

McDonnell Douglas knew that the door latch system was flawed back in 1969, Convair's Dan Applegate documented this in 1972 (Convair were fuselage sub-contractors).
McD ignored this and only made changes when the NTSB made them do so after two incidents, even then McD cosied up with the FAA who waived some of the NTSB requirements.
After the Turkish crash, McD implemented all the changes and re-designed the latch mechanism, did they know the system was unsafe, YES they damn well did.

FAA/NTSB disagreeing over the extent of fixes sound eerily familiar?

[glad rag]

Is the 787 Main battery getting a firebox as well? :hmm:

[eppy]

The 787 when cleared to fly will have a backup source for the brakes as the new battery and it's associated systems will have been certified as being safe and reliable.

Certified as safe: Yes. Certified as reliable: Highly unlikely.

The fireproof box and containment system appears to based on solid and proven engineering priciples, however will need to demonstrate its ability to contain the same failure scenario as on the ANA flight before it will be certified.

There are two ways to demonstrate reliability: The first is to deterministically ascertain and then eliminate the root cause of whatever caused the device to not meet the previous reliabilty certification criteria (i.e. 1 fire in 10 million hours).

The second way is to create a new device with moderate reliability claims based on engineering design, then to demonstrate higher reliability through accumulated service hours without incident.

The first method CANNOT yet be applied to the 787 battery as the root cause has not yet been determined. Most aspects of the new design such a separated/insulated individual battery cells, are containment improvements to offer better protection in the case of failure - they do not reduce the risk of the failure and thus do not increase reliability. Production changes such as tighter tolerances may help reliability, but there is no way of knowing without a deterministic confirmation of what the root cause failure mode is.

The 2nd method is what is commonly used for ETOPS certification. A new model aircraft/engine will typically have a moderate ETOPS rating based on the number of incident free test hours during certification. A case can then be made to increase the duration of the ETOPS certification as the number of incident free hours increases.

The problem for Boeing is that they don't have the luxury of time to go through thousands of hours of inflight testing of the "new" battery to demonstrate reliabilty using this method.

As such, I would expect the 787 to resume flights with a reduced ETOPS limit and stricter MEL (e.g. APU must be functional) until the reliability (or otherwise) of the "new" battery solution can be proven. I wouldn't be surprised to see additional operational requirements such as having the APU ON during takeoff, approaches and landings.

[toffeez]

Perrin, I don't see the link between Comet and A320. Comets crashed and killed people because of engineering failures.

The A320 hasn't done that, unless my memory has faded.

[Momoe]

Toffeez,

If you believe that the Habsheim A320 recorders weren't switched, then no.

Personally, I believe that at a crucial stage of the A320 implementation, the facts were massaged to present a more palatable truth.

[edmundronald]

There is a design problem in the 787 which won't go away - an APU battery failure makes the APU shutdown, so the APU is only as reliable as the battery - these two holes in the swiss cheese are aligned by design. Worse, deep discharge puts the battery at risk, but such discharge would likely occur exactly when starting the APU.

IN OTHER WORDS, THE FIREBOX PROTECTION OF THE APU BATTERY MAY PREVENT A THERMAL RISK, BUT BATTERY FAILURE DUE TO DEEP DISCHARGE DUE TO IN-FLIGHT STARTING OF THE APU WILL ANYWAY TAKE DOWN THE APU EXACTLY WHEN IT IS NEEDED.

The risk is that in case of a double engine malfunction the APU start process would deep discharge the battery, causing battery failure, and then the battery would be taken offline by its safety mechanisms which would take the APU offline and leave the plane reliant on the RAT, and possibly incapable of an engine restart.


I don't think the FAA should have certified this design logic, nor do I think they should certify it now. And yes, I may be an idiot but I'm an idiot with an electronic engineering degree and a PhdD.

[Kiskaloo]

edmundronald
There is a design problem in the 787 which won't go away - an APU battery failure makes the APU shutdown, so the APU is only as reliable as the battery - these two holes in the swiss cheese are aligned by design. Worse, deep discharge puts the battery at risk, but such discharge would likely occur exactly when starting the APU.

I don't think the FAA should have certified this design logic, nor do I think they should certify it now.

The APU on the 777 operates the same way - if the APU battery becomes inoperative, the APU shuts down. Other Boeing Commercial Aircraft families may operate similarly.


The risk is that in case of a double engine malfunction the APU start process would deep discharge the battery, causing battery failure, and then the battery would be taken offline by its safety mechanisms which would take the APU offline and leave the plane reliant on the RAT, and possibly incapable of an engine restart.

A double-engine failure is going to happen from one of two causes - FOD ingestion or fuel exhaustion. And both are pretty rare. Still, if such a scenario did happen, normal operation is for the Ship's Battery and APU Battery together start the APU, so the load is shared. However the APU battery can start the APU on it's own and I believe it can do so three times before the APU - not the APU battery - needs a "rest" before a fourth attempt can be made.

It is most certainly not a "one or done" situation in terms of starting attempts.

[Momoe]

Point taken regarding commonality of procedure between 777 and 787, however the 777's battery is not in question.

I make it at least 6, BA09 and KLM867 (Volcanic ash), ALM980 fuel exhaustion, RYR4109 is a strong contender for 7 (Written off after emergency landing following multiple bird strikes).

[henra]

The most important thing to think about is that their has been no souls lost on this B787 there are other startups that can't say the same (Comet,A320) to name two.


Did you go one step further than reading yellow press to come to this informed opinion? :(

[fizz57]

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

[cockney steve]

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!

[TURIN]

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.

[Hi_Tech]

The APU on the 777 operates the same way - if the APU battery becomes inoperative, the APU shuts down. ....

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??

[Hi_Tech]

Fitting the APU with a dedicated PMG to power the APUC would seem the answer.

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

[TURIN]

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.

[toffeez]

http://media-cdn.tripadvisor.com/media/photo-s/01/76/f9/1a/shemya-island.jpg

[Goddamnslacker]

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!

[blue up]

Was sent this yesterday. :O

http://i82.photobucket.com/albums/j279/foggythomas/lemon8lemon_zps8c9de1ad.jpg (http://s82.photobucket.com/user/foggythomas/media/lemon8lemon_zps8c9de1ad.jpg.html)

[MWorth]

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!

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.

[keesje]

US Federal Aviation Administration (FAA) chief Michael Huerta confirms that the Boeing 787's extended operations (ETOPS) certificate is being reviewed separately from the battery redesign investigation.

Addressing a Senate Commerce committee panel on the three-month anniversary of the Boeing grounding, Huerta's remarks clarified for the first time that Boeing has been answering the FAA's questions on two key fronts.

Boeing not only has to prove to the FAA that the 787 battery redesign and new containment system is safe enough. The company also has satisfy the agency that the 787 is reliable enough to fly routes that take the twinjet up to 180min away from an eligible runway.

http://binaryapi.ap.org/d2bf5b2482544e84b3a5862e13411b0e/512x.jpg

The ETOPS certification is essential for most airlines that fly the aircraft on routes over the war or even overland in remote areas of Australia.

"Coincident with [the battery] review was a review where we went back and looked at our original determination relating to ETOPS flight," Huerta told lawmakers.

"The question there is the airplane when it was grounded was certified for ETOPS of 180min," he says. "And so the question for us was would we return it at that level."

FAA reviewing 787 ETOPS certification separately from battery decision (http://www.flightglobal.com/news/articles/faa-reviewing-787-etops-certification-separately-from-battery-decision-384756/)

[Kiskaloo]

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.

[Romulus]

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.

[RCav8or]

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

[Kiskaloo]

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?

[golfyankeesierra]

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?

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

[Kiskaloo]

golfyankeesierra
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.

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.

[keesje]

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?

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 (http://online.wsj.com/article/SB10001424127887324595704578240172467982196.html)

[Kiskaloo]

In addition to approving the new 787 Battery Design, FAA spokeswoman Laura Brown said the agency hasn’t changed the Dreamliner’s ETOPS (“extended operations”) certification, which means the 787 will have continued approval to fly up to three hours away from the nearest airport.