BA B777 Incident @ Heathrow (merged)

[Lost in Saigon]

contactower makes a good point.

it would seem that at 600feet the crew tried to get more power...and it didn't happen.

if they had tried at 1500 feet there would have been more time to react

Tried WHAT at 1500'? Over-riding the auto throttles to add more power when there was no need to add more power?

Both you (sevenstrokeroll) and "contactower" make no sense at all.

The auto throttles are very precise and add or subtract just enough power to maintain a stabilized approach (descent) while responding to different wind conditions during the approach.

At 600' the conditions changed and that required more thrust to maintain a proper descent. No additional power was available and THAT is why they landed short.

[r011ingthunder]

I have to agree with Lost in Saigon, why override the autothrottle, if it seemed to be working at 1500'. When it displayed a problem at 600' they tried to override, and at that point the throttle control malfunctioned.
At least that's what I gather from AAIB.
r011in

[BuzzBox]

TAT Probe Icing??

TAT probe icing has caused problems for RR-powered 777s in the past - inability to achieve max rated thrust, thrust lever stagger, weird engine responses to thrust lever movement, etc. This problem was highlighted some time ago by a Boeing Bulletin, and later a procedure for TAT probe icing was incorporated in the QRH. The 'cure' was to put the engine EECs into ALTN mode, forcing them to use N1 as the thrust setting reference, rather than EPR.

Could this accident have been caused by a similar type of failure?

Anyone...???

[Elastoboy]

Please help the lower class!!!

As Danny "suggests" there is too much BS being offered that requires the "del" key being hit!
Please let us learn from this event!
When as a pilot (crew) the situation/information/fact/data is being thrust at you at an unusual and unexpected rate (e.g. big engines don't respond when asked) how should we react and process the priorities (sp)?
There is no question that experience is essential, but what was actually going through the flight decks heads? Instinict, training, self preservasion, or possibly all the above.
I have never been the the crews shoes and also many of us here have neither.
I hope that we can have an environment where all pilots can read, understand, inwardly digest and ultimately learn from the thought processes that were happening.

[grimmrad]

Simple question from a non-initiated

If I may ask a simple question: How do you (i.e. the experts) explain that some passenger(s) claim to have heard the engines go to full thrust similar to take of if the actual situation seems to be that the engines did not respond to any input. Seems to be a disconnect.

Also seems that the crew on board did everything they could to obtain the lucky outcome we got. Obviously (or at least according to the BBC) not necessarily the BA ground staff afterwards...

[FrequentSLF]

According to AIIB the engines failed to respond. Being a SLF I have a question, is there any logic that controls the T/L? Manual override is real a manual override or there is a logic on it?

[alph2z]

What is a power panel ?

......One area of specific interest will be the electrical system after it emerged yesterday that there had been at least 12 serious incidents of overheating, causing "major damage" to power panels on at least four occasions.

The initial findings of investigators are based on interviews with the pilots and analysis of the black box flight recorder and cockpit voice recorder. .....

http://www.dailymail.co.uk/pages/liv...e_id=1770&ct=5

.

[sevenstrokeroll]

dear lost in saigon

if the engines were at idle at 600 feet, were they at idle at 1500 feet? 3000 feet?

I know our company indicates that after a long idle descent, we should make sure the engines respond at 3000'. or be spooled up at 1500 feet.

now, we don't have trent engines...but are they so very different?

just wondering, have you ever heard of the above? you seem to think that it is very foreign.

now if the engines were at normal approach setting at 1500', and they didn't respond (change) when throttles were advanced, there might have been a better chance of making the runway.

we all come from different backgrounds in flying...and we should try to understand the other fellow.

[grimmrad]

if physicians had a forum

To bnt: No, there are no such fora to my knowledge. In fact, if you want to get some info regarding drugs or contrast agents some countries require that you are registered with proof of your license. Or before you enter the website some specific questions are asked, e.g. they show a CT image of the abdomen and ask where the pancreas is (A, B, C or D? Easy for me, I am a radiologist. probably tough for you). Hey - you guys could show a photo of the cockpit and ask where the autopilot is sitting (just kidding, but with a grain of truth in there. Easy for you but tough for me).

Patient confidentially also forbids discussion in the public, although there are several layman's webpages where you can ask questions.

[Farrell]

Grimmrad

Witnesses to any major incident will invariably have different opinions and testimony to what happened.

To give you an example... during a training course that I ran a while ago, in the middle of the class we arranged for two armed assailants to enter the class and snatch a course member, taking them "hostage" outside.

The operation from start to finish took less than twenty seconds.

With 29 people still left in the class, I asked for each one to give me a detailed written description of what they saw - paying particular attention to what the "kidnappers" said and what they wore.

The results were wide and varied - just like the descriptions of those involved in the Heathrow event.

I hope that this answers your question.

[EFHF]

Originally Posted by reventor

1) Did the pilots deliberately put the plane down on the grass?

If with "deliberately" you mean that they had a choice of touchdown somewhere else and still took the first patch of green after the perimeter fence:
Not known, like answers to all of these questions, but probably not.

Originally Posted by reventor

2) Would the outcome, in retrospect, likely have been as fortunate had they landed (with same force) on the runway?

Probably not, but landing with the same sink rate on the runway would not have been a reasonable option.
We don't know what the vertical velocity was at the time of impact with the grass, but probably it was in the region of survivable even as an impact with a harder surface (much below 2000 fpm). Disruption of the fuselage and fire has been a common result in impacts worse than which can just barely destroy the undercarriage.

Originally Posted by reventor

3) Was the stall-like nose up movement at the very end as seen in the video intentional or an unwanted consequence of whatever failures the aircraft suffered?

Probably intentional. The official AAIB initial information has revealed only failures with the engine response to throttle input, but does not yet rule out other problems. By Occam's they are extremely unlikely though, because the already very unlikely throttle problem fully explains the whole event.

Originally Posted by reventor

4) If intentional, what was the purpose of it, assuming the angle of attack was higher than it should have been for a smooth landing, as appeared to be the case to my untrained eyes?

The logical purpose was to reach the RESA or in other words the airport proper and avoid crashing in inhospitable terrain before it.

The crew probably traded momentum (speed) for lift to clear the boundary obstacles. It's a dangerous manouvre, but clearly justified by the results. Generally you would not want to slow down because this actually increases the sink rate, since you will be flying at a lower than optimal lift to drag ratio, resulting in an impact closer to the point of upset. But that scenario assumes you will be touching down at Vl/d, and not trading speed for more lift and more distance.

I think the main idea behind your questions is the assumption that the crew had a choice of landing on the runway, but I think the circumstances of the crash indicate that they didn't. If they had even a little bit of more thrust or speed while crossing the airport perimeter, they most likely would not have landed much further, but instead with less sink rate and less damage, still ending quite near where they did. It would not have made any sense to try to reach the asphalt with a presumably dangerously low energy state, but instead to try to arrest the excess sink rate which resulted in quite heavy structural damage and some injuries to the passengers and crew.

Originally Posted by reventor

5) It is generally not entirely unreasonable to assume that the timing of the failure was crucial? A little shift in time and they either fall down in the residential area or make a reasonably normal landing.

I think it's a good assumption. It has been speculated that the approach may not have been properly stabilised, having support mainly from eyewitness accounts, which would explain the throttle demand at that specific point of failure. However, it was a relatively gusty day and some (larger than average) throttle adjustment was necessary for even a perfect approach.

[Intruder]

Just received this exclusive transcript of the last couple of minutes on the CVR.

Outstanding, corsair! You had me going for the first 5 lines! The giveaway was when you omitted the obligatory trouser cleanup...

[Gipsy Queen]

"If you compare a pilot to a surgeon, there are certain similarities: they both perform a very technical task, sometimes over long hours, and if they cock it up, people die. I wonder if surgeons go on medical forums, and moan at GPs or patients for discussing medical procedures? "You're not a cardiac surgeon, so stop speculating about failed pacemakers!"

I say, steady on! If these professions are in any way analogous, I'm going by sea.

Don't know about elsewhere but the National Academy of Science's Institute of Medicine cites avoidable medical mistakes as the eighth leading cause of death in the US; ahead of car smashes, breast cancer and AIDS. Furthermore, there is no legal limit placed on the number of hours a physician may work in a given period and 70% of surgeons do not believe that fatigue affects their performance in the operating room. Since there are no Federal laws requiring hospitals to report deaths and injuries to patients caused in error, the picture could well be bleaker and probably is.

If these statistics (or anything like them) were applied to our business, we really would have a problem.

[RiversInAustin]

L'dOL

Thanks very much corsair for a classic pprune post that made me LOL several times. After 28 pages it was very welcome.

Rivers

[misd-agin]

EFHF - thank you for a reasoned response.

simfly - you get it. So does MikeAlphaTangoTango.

Power was at X. They asked for X+. "Engines did not respond."

No one here knows what X was.

The AAIB report mentions -

Following further demands for increased thrust from the Autothrottle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond. The aircraft speed reduced and the aircraft descended onto the grass short of the paved runway surface.

They're at 600'. They should be very close to stabilized Vref. So why did the AAIB include that statement? We'll have to see what the facts are when the AAIB releases them.

[Crankhandle]

Professional Press V Professional Pilots

If only the Worlds press corp, and I mean all of them, could show the professionalism in their articles, that an airline pilot shows in conducting a standard, run-of-the-mill approach to land, then some of their articles may be worth reading. I don't believe it possible for a "journalist" to even remotely understand the professionalism required to do what this crew has achieved, whatever the cause.
This may be a rumour network, I think rumours are healthy, don't get me wrong, but oh boy, are there some doozies here today, some of the weirder ones are great for feeding to the press sharks, they show them up for the idiots they are. There is some very informative debate here as well but lets remember that until the official version comes out we are only guessing.
To the crew of the triple seven, congratulations, to the hungry press, butt out.

[archae86]

Times article

The Times (casually referred to by many of us outsiders as the London Times) has posted an article here:

Times article

Ignoring the sensational title and such, it has a few factual claims which I've not seen before.

1. the aircraft slowed enough to enter stick shaker early in the incident.

2. a mayday was issued "the moment that they hit the grass".

3. the pilots first observation of abnormality was directly of reduced speed, possibly because some warnings were inhibited at low altitude.

I'm not a pilot--please remove this post if my extract is misleading or the link not possibly useful or interesting.

[Teal]

I'm an ex-ATC, non-pilot, with a couple of questions for the experts:

1. Given the reportedly gusty wind conditions, is it possible that the two engines may have flamed out/stalled at that critical moment - 600' up and 2nm out?

2. Assuming there were no fuel problems, with the aircraft's multitude of electronic and digital systems controlling almost all aspects of the plane's operations, how uncommon or unlikely is it for both engines not to respond to throttle commands?

[misd-agin]

Teal -

1. It's gusty all around the world, in different places, all the time. The engines are designed for these conditions.

The engines did not stall. They stayed at the power setting they were at. We don't know what that power setting was but obviously it was lower than was needed.

2. Ah, this might be the heart and soul of the investigation. What happened? We don't know.

It's not common at all. That's why this is such an interesting event for professional pilots.

Years ago RR engines on 757's had what we, on the sunny side of the pond, call 'deep idle stalls'. What were the symptoms? Push the power up and the engines just stayed at idle. Obviously it never developed into an incident. Is that related to this event? It's waaaaaay to premature to suggest any link between the two.

[TwinJock]

Facts - or as close as can be:

Fuel - NO Problem

Weather - NO problem

Pilot Error - NO Problem

If I am MR or Mrs Rolls Royce, I would be worried at this stage. More and more fingers pointing in their direction.

Great Job by the CREW!!!