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AAIB initial report out on BA B777 crash at LHR

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AAIB initial report out on BA B777 crash at LHR

Old 20th Jan 2008, 08:44
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but you wouldn't blame any 777/Roller drivers ditching the noise abatement idea and arriving with just a little more thrust or Kinetic Energy up their sleeve
I might agree with you on Thrust... but in fact KE is controlled / determined by ATC, and PE is higher on the CDA
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Old 20th Jan 2008, 08:54
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·Should the captain have taken a few seconds away from his checking to at least flash the seat belt sign to confirm to the cabin crew that any preliminary suspicions they had that things were serious were correct?
No. There were more important things going on at the time I believe. If he had the chance, I'm sure he would have made the crew aware.

·In the absence of any communication from the flight deck, should the cabin crew have taken the initiative to instruct the passengers to the brace position?
No. With respect to my cabin crew colleagues, unless they have been prewarned, they have no way to know whether or not a landing is likely to be abnormal until it's finished.

·Does the FO in the jump seat have any ability to communicate to the cabin crew the need to get the passengers into the brace position?

·If the FO could not communicate himself should he have suggested to the Captain that he should do it?
Maybe, maybe not. Perhaps he did, perhaps he didn't. There are a million reasons why it was perhaps not communicated to the cabin. All of them valid.
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Old 20th Jan 2008, 08:56
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Adding up

It is very interesting to debate all possible causes of this accident & some of it has been v enlightening but one central issue goes unadressed - if we don't know how the impossible happened why are 777s still flying & what's more on ETOPS?

Two independent engines with independent control systems, both with redundancy and still both engines "fail to respond." No cause for global concern there then? Sumat doesn't add up.
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Old 20th Jan 2008, 09:00
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·Why with three pilots on the flight deck, did not one of them initiate the order to evacuate?
I believe one of them did.

·How appropriate is it that passengers end up initiating evacuation before the cabin crew?
It isn't.

·How appropriate is it, for the cabin crew to order passengers attempting to evacuate a plane highly likely to catch fire to return to their seats?
There may be reasons why it is initially safer to stay inside than jump out. An evacuation can potentially cause more injuries than an incident. At the very least, if you have a few seconds to evaluate the situation before you initiate the evacuation, I would recommend using them.
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Old 20th Jan 2008, 09:07
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"Late Finals" a final word?

"until the aircraft was established on late finals for Runway 27L."....

I think the report author would have prevented this line of discussion by more accurately calling it "Short Finals" or "Very Short Finals".....?
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Old 20th Jan 2008, 09:08
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"...the aircraft was at a height of approximately 600 ft and 2 miles from touch down. The aircraft then descended rapidly and struck the ground, some 1,000 ft short of the paved runway surface,..."

Considering the aircraft was 2 miles out and managed to get within 1000' of the runway, can this be considered a "rapid" descent?

Re fuel contamination ex-Beijing... I've been told that our airline's Airbuses (ex-China) regularly generate blocked filter messages (and have to be replaced). I didn't ask what steps have been taken to address this issue, however.

Re jet pumps getting rid of water in the tank... .Can it get rid of water if it is in the form of ice? Cold flight there, cold ground stop, cold flight back, etc.. Will it ever get the chance to thaw out?


In Normal Mode (EPR), the EEC uses this data to calculate thrust ratings:
Thrust lever angle (TLA)
Inlet temperature
Mach Number
Bleed Status

In Alternate Mode (N1) the EEC uses this...
Inlet temperature

Some faults make the EEC switch to alternate N1 mode automatically. This is called soft reversion. When soft reversion occurs, the EEC turns on the ALTN light in the EEC mode switches. The EPR indications also go out of view.

Re P2T2 heat... (engine inlet probe heat)

There is a device called a PCU (power control unit, mounted on the side of the engine) which supplies heating power to P2T2 probe. The PCU can get it's power from the dedicated alternator (driven by engine rotation) or from ELMS (normal airplane power). There are switching circuits inside the PCU. Full details not available to me, but it seems the EEC has the ability to control what power source the PCU selects (but I don't know if this is at all times).

The EEC monitors probe heat current. There are maintenance messages for probe heat failure, but the pilots only know of probe heat failure though EEC mode EICAS and Status messages.

Information about EEC's derived from Boeing 777 Maintenance Manual (D&O).

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Old 20th Jan 2008, 09:16
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Might I note :-

- This thread started off quite sensibly as a thread to discuss the AAIB initial report, it now seems to be starting to be a re-hash of the "other" thread.

- The AAIB initial report was so uninformative and SEEMINGLY deliberately so, that MAY INDICATE that the cause MIGHT at FIRST GLANCE be one that is going to be difficult to apprortion quickly. (The whole dearth of facts merely gives rise to having to be so cautious).


The only sensible comment that I can think to make is that I think that this is appalling PR, merely guaranteed to get people speculating. If the AAIB, BA and BAA want to keep public speculation, popular concern and the media feeding frenzy down, then they should be more forthcoming in their Public Relations. As a display of media control this is appalling.

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Old 20th Jan 2008, 09:23
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p.s. As Nugpot (Topgun???) has discovered the Boeing system moves the thrust levers to give tactile feedback and an early indication that power is not coming up. The Airbus system just leaves the thrust levers where they are, does its thing and leaves you to guess the power setting.
Oh for heaven's sake,here we go again..... Just how did the thrust levers give this early indication? The pilots had to look at the instruments, just like all pilots do. It's always a guess, irrespective of a/c type until you use your eyes. And your brain.

I agree about the 'gentle nose down pitch' of the airbus making a mess of your nice extended glide though.
Lots of people have died doing nice extended glides... Stalling at 100' instead of 10' might have made a huge mess of a 777 if a wing dropped - I don't know the stall characteristics or anything about the 777 Flight Control System - I think the success of this particular landing was down to the ability of the pilots and not the design of the a/c.
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Old 20th Jan 2008, 09:24
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TOGA..... or not to TOGA

Belgique's TOGA idea (posts 922 and 939 of closed BA B777 Incident @ Heathrow (merged) thread) might just have worked.
It is counter-instinctive for a pilot to attempt to go around if he knows he does not have enough power even to maintain his desired descent, and for this reason it was almost certainly not tried.
If his idea had been thought of and tried and worked the whole thing would have been hushed up and they would not have been heroes. I think they would like that trade.
Software instead of being our able assistant is really becoming our enemy.
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Old 20th Jan 2008, 09:24
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The key for the AAIB is to discover why the engines did not respond, and then prevent that happening again (basic premise of accident investigations). We are dealing in public transport aircraft here, and we really cannot take your logic to the extent of joining LHR overhead at 3000' in a PFL pattern because of one occurence
I know we are dealing with a public transport aircraft, thanks. I fly them too.

If you would re-read my post #9, you'd see that I am not suggesting that absurdity. I have asked if anyone else thinks that this might call into question the practice of CDA. That is all.

Last edited by Wingswinger; 21st Jan 2008 at 07:24.
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Old 20th Jan 2008, 09:31
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the A/T system is not a separate system on the B777 as on other 'fly-by-wire' aircrafts. when the A/Ts are engaged, the A/T servos moves the throttle levers just as a pilot will normally do, based on the A/T computer inputs. one can manually 'overwrite' the servos by physically moving the throttle levers but if you released the throttles, the A/T servos will move the throttle levers back to it's 'current commanded' position.


On an approach does the AT cycle the levers constantly??

And how apparent to the PF are these lever monements???


glad rag
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Old 20th Jan 2008, 09:31
  #32 (permalink)  
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Well done to all involved, including Cabin Crew :)

" I would expect that most of the cabin crew located near windows would have enough general flying experience and specific LHR approach experience to know something very abnormal and potentially dangerous was occurring in the last 30 secs of flight."

Incorrect, the windows on those Boeing 777 doors, by the Cabin Crew seats, are extremely small and it is nearly impossible to see what is going on outside (same as 767, windows on doors are too small!!).
This should be in fact reviewed and the window design changed. Cabin crew should always know what is happening outside (fire, etc).

Apparently those passengers seating by the "larger-normal" windows, and especially those by the wings, immediately realised that this was a crash-landing on the grass and they went straight to the exits with some degree of very understandable panic. Only after this the CSD correctly and bravely decided to evacuate.
You can do all the training you like but this was the totally unexpected "engine-throttle failure" with only a few seconds left to react. Seconds. No time to follow procedures or check-lists, just the minimum time to concentrate on your skills and istinct. This is why the absence of a side-stick (Boeing vs Airbus) might actually have helped in this case, but this just my personal speculation.

After the plane stopped, the pilots were obviously still seriously shocked after landing and they probably thought they were in the middle of a dream and all pax died at the back...it was their worst nightmare... and I applaude them for an incredible landing.
They did not know what happened behind their door until they heard the pax evacuating....our brain is not as cold as a computer...plain traditional feelings and istinct have saved this plane and those on board and those on the road and houses nearby as well.
It seems like our beloved electronic and FBW concept has failed (!) again and the only bit of "human factor" left has actually saved the plane. Unless it is fuel related.

It is impossible to understand here what they went through in the cockpit, the mental shock is extreme and they were possibly all shaking. Normal. Nobody is prepared to land on the grass just missing cars and houses on a 777...nobody. Especially so suddenly and after 12+ hours of perfect flying..

They have all done an exceptional job.

The plane stalled, luckily, at the perfect stage, and in fact also stopped in an incredibly short distance. And this is exactly what the pilot should have been looking for and he made it.
Anything else is irrelevant to me.
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Old 20th Jan 2008, 09:35
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Ramrod2 is technically correct in his post as he did not mention the fuel tank quantity.
The reason this aircraft ended up as it did is most likely down to fuel in one way or other.
I point this out because if the engines at the time the crew demanded more power had been supplied more fuel, they would have produced more power.
The question that the AAIB has to answer is why did the engines not get this required fuel.
The point is that the FADEC along with all the other hardware and software did not supply that extra fuel when demanded.
I have read the following "The AAIB has identified that the problem seems to be connected with the avionics and and electrics which link the flight deck to the engines."
It is to early to point fingers or give praise as we do not know the facts.
The most likely to end up with some or all of the blame are going to be the following, Crew, BA, Boeing, RR or other component manufactures associated with engine controls.
Everyone has assumed that this aircraft was fully serviceable before the accident, we do not know what technical defects it was carrying prior to departure and don't know what defects it had on route.
This is why l put the crew and BA into the possible blame, as we know it sometime takes many independent items to combine to cause an accident.
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Old 20th Jan 2008, 09:36
  #34 (permalink)  
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777 Incident

AAIB quote: "the Autothrottle demanded an increase in thrust from the two engines but the engines did not respond".

An observation only: Occurring only 2 miles from touchdown at 600', is this not totally unique in commercial aviation?
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Old 20th Jan 2008, 09:37
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Reply to Giant Bird

I know you mean well GB but your reasoning and assumptions, as well as your suggestions are incredibly hindsighted and dare I suggest what I would expect from a desk pilot or civil servant who has an excellent grasp of theory but little of reality.

Two miles out and 600' agl, engines lose power over a residential area and it takes all the skill and concentration of an experienced crew to get the aircraft onto level ground rather than the nearest road embankment or house, and you expect the crew to take time out for a message??? To anyone??? To anywhere????

There may be valid points in your second part about the evacuation order control, but once again I say that they are from the point of view of an observer, not from someone who was there at the time. Perhaps if you could qualify your statements with a statement to the effect that you are an expert crash manager, and when you brought in such and such a plane to a successful crash landing against the odds, you had the ice cool ability to do everything by the book, to the letter and per every last regulation under the cloudy London skies.

Get my point?
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Old 20th Jan 2008, 09:40
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Only after this the CSD correctly and bravely decided to evacuate.
Where have you got the info that the CSD decided to evacuate I have seen no concrete info that this occurred, rather, than say the evacuation was initiated from the Flt Deck
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Old 20th Jan 2008, 09:42
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AAIB quote: "the Autothrottle demanded an increase in thrust from the two engines but the engines did not respond".

An observation only: Occurring only 2 miles from touchdown at 600', is this not totally unique in commercial aviation?
Do you mean is the requirement for thrust at this point in the approach "unique"? No.

If you mean 'Is it unique for the thrust not to be supplied when needed?'. Probably. I've not heard of any other crashes matching this scenario.
Old 20th Jan 2008, 09:42
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Report reads: F/O took time to address the pax to prepare for a ...........FDR/CVR stopped due stall at 300' and crashed and burned a whole suburb

Would rather not hear a thing and actually have an aircraft .....and the physical ability to get out of it.............

Stuff the PA's......I thought .Aviate, Navigate Communicate was pretty clear, and in that order.

Regardless if they stuffed up with fuel or something, they got that last bit right.

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Old 20th Jan 2008, 09:42
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The A/T will move the thrust levers if it's required to maintain selected airspeed. Most SOP's require the pilots hand to be on the thrust levers during the approach. If the approach is stable in a zero wind condition there will be little if any movement of the thrust levers by the auto throttles once the aircraft is established on final. In gusty conditions where thrust requirements change constantly the A/T will move the thrust levers quite a bit to maintain speed and movement is instantly noticable if your hand is on the thrust levers.

In CDA approach the thrust will remain near idle as the aircraft slows down to final approach speed and the aircraft is configured in the landing configuration. The thrust will then increase to maintain speed. Most airlines (BA included) have "gates"'in which the aircraft must meet certain stabilization criteria or a GA is performed. One of the last gates criteria is the aircraft is on speed and the engines are spooled up above idle. As i understand it BA's last gate is 500' so likely the thrust was coming up from an approach idle configuration to maintain speed and failed to respond at that time.

A crappy situation with very little time to recognize it and take any sort of action other than flying the aircraft. I highly doubt a PA was very likely given the amount of time they had to recognize and deal with the situation, especially considering the length of flight they had just done...you certainly aren't expecting an issue like that 600' above ground on final after a 12hr + flight.
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Old 20th Jan 2008, 09:47
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Re Giant Birds comments:

As I understand it the pilots didn't have time or were too busy even to issue a Mayday call before impact. They did that immediatly after coming to a stop and that was probabably simutaneously with the cabin crew ordering an evac. Presumably the pilots heard the cabin crew order the evac as well. Knowing that a call had been made perhaps making sure everything was shut down was higher priority. Anyway the CVR transcript will no doubt make it all clear.

I've not heard any passengers say they knew they were going to crash and they would have had a better view out of the windows. Can cabin crew even see the ground from their seats? Aren't they normally busy looking for pax standing up to retrieve hand luggage?
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