BA B777 Incident @ Heathrow (merged) [Archive] - Page 3

TURIN

19th Jan 2008, 00:39

Many, many years go, when I was a young pilot, there was an incident in where I live, with Airbus A300's. Company was Karair, at that time a charter subsidiary of Finnair, they had two A300's, with highest utilisation of the type then, basically flying non-stop between Finland and the Canary Islands. About 18 hours airborne per day per aircraft, if I recall correctly. At some point, it was discovered that there was a huge chunk of ice floating in the fuel tank of one of the aircraft, as the condenced water never had time to melt, and thus had never been drained from the system between the flights. The aircraft had actually been very close to fuel starvation because of this. Of course, about 20 years have passed, lessons have been learnt, and this could not happen again, couldn't it...?

Now this rings a bell.

I think about 10 years ago Continental had an issue with their early 777s in that during winter ops from NWK the fuel temp never dropped sufficiently to allow any suspended/solid water to thaw and therefore be drained during normal routine checks. Result was a very large, thick sheet of ice in the base of the fuel tanks which would often give erroneous tank qty readings.

I have no idea if this has anything to do with recent events. I just wanted to comment on the above quote. :ok:

BTW. I heard Danny on BBC R2 today. Excellent. Kept to the facts as known and refrained from speculation. However, as soon as Danny had signed off the R2 DJ, Jeremy Vine, then asked the listeners to "ring in with tales of any near miss experiences they had". :mad::*

bnt

19th Jan 2008, 00:39

First time poster, followed link from Wikipedia.
OK, I have nothing to offer to this already "hot" debate, but I do have one or two things to ask:
(snip)

1) This specific forum is called "Rumours & News", too. There are other forums that are airline-specific, including some locked to staff only.
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!" :8

2) Self-Loading Freight. The implication is that airline passengers are dead weight, and should not be seen or heard from. As an insult, it's not working, so you'll see it used by passengers in a way Alanis Morissette would appreciate.

3) I thought two had mentioned it? ;) My SLF opinion is on that is somewhere between a) probably not, it would surely have been noticed, or b) could have had an effect on other components, but premature to speculate e.g. a lot of talk in this thread about possible FADEC problems, but it's not been reported that there were any such problems, so it's pointless to worry about an indirect cause like lightning at this early stage in investigation.

4) Deities have sod-all to do with it: thank the pilots, and Boeing engineers. :}

sevenstrokeroll

19th Jan 2008, 00:40

flutter

19th Jan 2008, 00:43

Reading some of the posts regarding this awful incident which I hope never happens to me in my flying career, respect that the crew are in massive shock at this stage. They did a great job!

Nobody has an idea what happened apart from the crew, AAIB and flight safety in BA.

flipperb

19th Jan 2008, 01:11

As I noted in my last post, I'm not a pilot, so feel free to take this with a grain of salt...

IMHO, the evidence doesn't seem to point to any sort of fuel or other engine problem. For both engines to stop responding to throttle input sounds much more like a problem somewhere in the FBW path.

So here's my theory/question... If the computer thinks that the a/c is in an overspeed situation, would advancing the throttles be "ignored"? I haven't heard anything about alarms (such as overspeed) in the cockpit, but what would happen if somewhere in the electronics, an overspeed sensor/algorithm malfunctioned? Is it possible that this would interrupt the throttle commands from both a/t and manually advancing the levers?

safetypee

19th Jan 2008, 01:12

Certain types of engine icing might lead to an unresponsive engine, and this could affect both simultaneously; or with decreased efficiency on one, the other engine struggles which might make it more susceptible to the effects of ice, so shortly after both are affected.
Although most engines are anti-iced, some of the big fans rely on fan-ice shedding (centrifugal action) at higher rpm. Thus during an approach with relatively lower rpm and in unusual conditions of a lengthy exposure to the ‘exact’ icing conditions (and possibly without engine anti icing) problems might be encountered.

IIRC the smaller fan F100 and 146 engines suffered fan icing in freezing conditions when taxiing – low engine speed. Some aircraft types also suffered from this in-flight (exceptional atmospheric conditions) where the situation was usually indicated with a Vib warning and cleared with an increase of thrust (within the temp limits).

Ice can affect the efficiency of the engine (mainly fan thrust); autothrust seeks to adjust thrust to maintain desired airspeed, the engine is reluctant to respond / insufficient thrust (due to the effect of ice), more thrust lever input, mismatch in fuel/air/engine speed ratios; - bad situation turning worse.
At what engine speed does a Gen come off line during an in-flight shutdown (normal shutdown – ice free windmill characteristics) or in a sub idle condition?

Lost in Saigon

19th Jan 2008, 01:44

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

19th Jan 2008, 01:52

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

19th Jan 2008, 01:55

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

19th Jan 2008, 01:57

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

19th Jan 2008, 02:12

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

19th Jan 2008, 02:17

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

19th Jan 2008, 02:38

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/live/articles/news/news.html?in_article_id=509163&in_page_id=1770&ct=5

.

sevenstrokeroll

19th Jan 2008, 02:39

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

19th Jan 2008, 02:42

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

19th Jan 2008, 02:43

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

19th Jan 2008, 03:04

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.

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.

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.

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.

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

19th Jan 2008, 03:09

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

19th Jan 2008, 03:17

"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!" :8

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

19th Jan 2008, 03:24

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

19th Jan 2008, 03:31

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

19th Jan 2008, 03:39

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

19th Jan 2008, 03:40

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

Times article (http://www.timesonline.co.uk/tol/news/uk/article3213335.ece)

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

19th Jan 2008, 04:01

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

19th Jan 2008, 04:15

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

19th Jan 2008, 04:19

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!!!

Teal

19th Jan 2008, 04:28

Misd-agin -

Another question if you don't mind: could contaminated fuel nozzles be another possibility? The fuel was uploaded in China and a sustained period of engine idle on descent may have led to some build-up or coking. It has happened before. Just a thought.

misd-agin

19th Jan 2008, 04:38

Teal,

Beyond my technical ability to respond. Planes have been flying into, and out of, China for decades.

To say it could been this, or could have been that, is pointless IMO.
It could have been a zillion things.

No one's brought up the chance that it could have been two expert rifle shots at the same time to both hit the fuel control units in the exact same spot. :ugh:

No one's brought the chance that it could have been a meteor that broke up in space and two small pieces hit the engines in the exact same spot. :ugh:

Patience. They're working on it.

Lost in Saigon

19th Jan 2008, 04:39

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

Nobody said they were at idle at 600'. They would have been at approach power or close to it.

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.

That is very foreign to me. I currently fly B767's with both P&W, and GE engines. I used to fly F28's with Rolls Royce Spey's. I have never heard of anyone doing anything remotely like what you describe. On a piston engine sure, but not a turbine engine. On what engines do you use that procedure?

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.

uniuniunium

19th Jan 2008, 04:40

There has been much discussion of the T7's APU and RAT and their respective abilities to provide power during a dual engine failure, but no one has brought up the ability of the two windmilling engines to provide limited power/hydraulics. I really have no sense of how effective the Trents might be in this situation (airspeed and given spooldown time, assuming a flameout), but my remembrance is that the donks on a 74' can provide sufficient power to operate the aircraft while windmilling in a four-out situation. It seems unlikely based on the initial reports that the APU could've autostarted fast enough to be useful, and the same seems true for the RAT (might've deployed but unlikely to have had time to spool up). Would the windmilling engines be effective in powering the essential systems for the 30 seconds or so between the loss of power and impact with the ground? I'm thinking this might also explain the pax reports of flickering lights, e.g. load shedding occurred as the engines were unable to sustain full bus load.

pasoundman

19th Jan 2008, 04:45

" OK, we know the 2 engines failed to respond simultaneously.
This is very strange, they are totally independent: only a couple of bits are shared, either fuel or throttle. "

The 2 FADECS for the engines are indeed independent but how about the autothrottle itself ? Is that perhaps a possible single point of failure ? Just asking.

Incidentally didn't early A320s have a software bug where the engines sometimes failed to respond to the throttles ? To fix it you had to close the throttles and then open them again.

Graham

Lost in Saigon

19th Jan 2008, 04:46

no one has brought up the ability of the two windmilling engines to provide limited power/hydraulics.

uniuniunium,

The engines weren't windmilling. They were producing power. It is very normal for a jet aircraft to need an additional power adjustment as it approaches the runway. For some unknown reason the extra power called for was not able to be delivered.

uniuniunium

19th Jan 2008, 04:58

The engines weren't windmilling. They were producing power. It is very normal for a jet aircraft to need an additional power adjustment as it approaches the runway. For some unknown reason the extra power called for was not able to be delivered.

Well, I suppose my question is slightly outdated, now that the working theory seems to indicate lack of throttle response from two otherwise running engines, I'm quite aware that under normal operating conditions, the engines would've been spooled up on finals. I should've phrased my query in more general terms, rather than asking about "the" pair of engines in question. I'm still curious to know if they would've been able to provide enough power to fly the aircraft (without the hydro/mechanical backups) in the event that they were windmilling.

Lost in Saigon

19th Jan 2008, 05:05

I doubt a windmilling Trent would provide any electrical or hydraulic power.

But it is a three-shaft engine so it would depend on which shaft each accessory is attached to.

expat400

19th Jan 2008, 05:09

What do we learn from this?

Forget the "Stabilized Approach"!

Had they had 20+ knots above Vref they would have made it to the runway;)

"No, i'm not going around. I'm not unstabilized... I'm just preparing for non responsive engines" :ok:

acmi48

19th Jan 2008, 05:13

most airline personal are not allowed to discuss any issues with the media,by virtue of their contracts ,in case of any incident/accident this is drilled home on every page of the EM. the engineer quoted after the incident altho well meaning is actually on dangerous territory.

the press have a job to do- so leave the speculation to them and bite the bullet when it comes to reported inaccuracies,the story is off the main headlines now and the real business of finding out what went wrong can start

ExSimGuy

19th Jan 2008, 05:31

(I'm 30 years non-current, so bin this if totally irrelevant)

Engines vs fuel

Way back in the distant past of 707s,747s etc,SOP was to feed tank-to-engine for T/O and APP, Crossfeed was only used for "non-critical" parts of the flight. Is this still so?

I'd feel far more likely to suspect some engine condition triggered by simultaneous throttle movement than the simultaneous problem condition occurring on both tanks (ice,water,whatever) on opposite sides of the wing.

Is it still tank-to-engine during approach these days?

soggy_cabbage

19th Jan 2008, 05:32

Yes The aircraft didn't want to die a horrible screaming death!.

Just wondering how much the "landing" was due to the pilots and how much was done by the computers. The 777 is after all fly by wire.

The final report will be very interesting to read. What did the aircraft systems do automatically in response to the lack of the command to the engines to increase power.

Really happy no one was seriously injured and the aircraft can be examined in depth. This will be a real life test flight.

puff

19th Jan 2008, 05:44

After so long without a 777 hull loss i'm sure Boeing is going to be very interesting to see how their 'latest' held together, must say under the impact it didn't break in any of the usual 'joins' used in manfacture and stayed pretty well intact. I'm sure the 'structure' engineer is sleeping a little sounder than the electrical one!

pasoundman

19th Jan 2008, 05:57

" Certain types of engine icing might lead to an unresponsive engine, and this could affect both simultaneously; or with decreased efficiency on one, the other engine struggles which might make it more susceptible to the effects of ice, so shortly after both are affected.
Although most engines are anti-iced, some of the big fans rely on fan-ice shedding (centrifugal action) at higher rpm. "

I don't see anyone other than you suggesting that the engines themselves were 'iced up' !

B A Lert

19th Jan 2008, 05:58

Let us all give thanks and praise, not only to the boys and girls on the aircraft, but also to those who train and maintain their standards. In a time of great cost-cutting and reduction in standards, it is most reassuring to know that when the sh!t hits the fan, the professionalism and training of the crew came to the fore. Well done to all concerned and good luck. :D:D:D

ankh

19th Jan 2008, 05:59

Having started flying hang gliders in 1978, just at the end of the 'full luff dive' era when they'd started building them with a bit of an airfoil and dive recovery instead of loose flapping Rogallo fabric, a lot of us learned a great deal from other pilots' stories, the "there I was, though I was gonna die" recitals -- honesty being the core of these knowing some bit might save another pilot's life another day.

Only question I feel might be askable at this point is -- for those of you who fly real airplanes -- will you approach your flying any differently knowing no more than you know now, that there have been several of these power failure events recently, for whatever reason?

They told me 'altitude, airspeed, and ideas' -- two out of three ain't bad.
So I'm wondering if knowing this has happened to several aircraft is going to change y'all's ....er ... approach, or flying, in any way?

Got anything y'all care to say about how you'll fly, with just this bit of knowledge that this can happen? Is it news enough to make any difference, before we know specifics, just to say, this too can happen?

ext332

19th Jan 2008, 06:04

I've been thinking about this event over the last few days......

One question, does anyone else share my unease about heaping praise on the crew until the full results are in, I seem to remember something similar regarding Kegworth for the first three days after that incident.

I wonder if there is any hint at a late stabilisation and subsequent slow spool-up after 500 ft

Might explain why Boeing haven't grounded the fleet.

Hope I'm wrong

ExT

rogerg

19th Jan 2008, 06:05

Just wondering how much the "landing" was due to the pilots and how much was done by the computers. The 777 is after all fly by wire.

Fly by wire, fly by cable, fly by rod, or whatever, I am sure the pilot was operating the controls, as the autopilot would not be connected under those conditions. I suspect that inertia was in control with a panic pull at the last few seconds. A bit like some of my landings!!

HotDog

19th Jan 2008, 06:05

Wouldn't need to as the RAT would deploy for the loss of either. I have on a few occasions, observed hydraulic pressure indication from a windmilling RB211

pasoundman

19th Jan 2008, 06:06

" I believe that the engines problems may have been caused by electomagnetic interference caused by electrical jamming of the electrical components of the engine controls. Perhaps a strong signal emanating from a device on the ground. "

Al Qaeda ? (I'm not being terrribly serious but wondering if that's what you meant).

Seriously I don't think that's very likely. Not IMPOSSIBLE I dare say, just very very unlikely.

Kapitanleutnant

19th Jan 2008, 06:19

PaSoundMan

If I'm not mistaken, the 777 has an automatic icing detection and activation system on it. Been a few years since I flew it at my airline as FO, but it was essentially a no brainer system and whenever the system detected icing, it atuomatically turned the anti ice system on for the engines. No real input needed by the flight crew. Can someone confirm?

Not to say that system was inoperative, though.

K

Halfnut

19th Jan 2008, 06:24

ankh,

With three recorders taking a constant pulse of this plane I would think the AAIB will be able to narrow down the cause of this accident real quick. The AAIB has already said they will be coming out with an initial report in thirty days so I’m confident a “fix” will be out well before the final report which can take as long as two years.

I fly a “Cable Car” plane so I try to stay out of these kinds of discussions but giving the excellent safety record of the triple seven (and all others), the length of service the triple seven has been operating i.e. how many approaches/landings it has done successfully, I don’t see this happening again.

The landing profile that is currently flown by all operators has been honed over many years by other accidents so to compensate because of this accident will only off set the curve somewhere else. I’ll stick to flying the plane the way we’re trained (for now).

cwatters

19th Jan 2008, 06:31

The spokesman (AAIB?) I saw on TV last night said the plane was at 600 foot when it dropped very slightly below glide slope (journalists - note he didn't say that in itself was abnormal) the auto throttle commanded more power as it is designed to do but engines didn't respond, (can't quite recall exact words but something like) pilot then switched to manual and advanced the throttle but the engines still did not respond. Presumably they continued to drop below glide slope (which obviously was abnormal!).

Ex Cargo Clown

19th Jan 2008, 06:43

Ok, I'll bite.

Some of the speculation on here is just insane. We've had ridiculous, unfounded suggestions, including and Electro-Magnetic "weapon" fired at the aircraft, lightning etc, I'm only suprised Aliens haven't had fingers pointed at them yet....

It also seems people are either completely oblivious, or just ignoring the facts.

As far as I know the facts are.

1) The engines did NOT "stop", they just ceased to produce commanded thrust.

2) The aircraft did NOT run out of fuel (see 1)

3) Wx was NOT an issue

As for those "barrack-room" pilots criticising the pilot for not been stabilised at 1500ft :ugh::ugh::ugh: Ever heard of the 160 to 4 requirement at LHR ?

I'm not going to speculate anymore on this, applying Occams Razor to this is clearly a difficult exercise.

Earl

19th Jan 2008, 06:44

On the RR 524 I seem to remember a switch that could be placed in over ride that would reset the fuel control in sub idle conditions.
Did something to the fuel control amplifier.
Over speed protection was out the window then and had to be watched.

Ian W

19th Jan 2008, 06:53

"It is unlikely that the pilot would lower the undercarriage at such a low altitude (approaching 400ft), unless he was already aware that he had to stretch the glide slope by keeping the aeroplane in a clean configuration, and there is no evidence of that (yet)."

It is more likely that full flap was selected at around 2 miles and as the drag increased there would/should be a demand for more thrust from the engines. If they then remained frozen at the previous percentage the perception would be loss of power.
Does anyone know: (1) the flap settings and speeds/altitudes in a B777 on finals? (2) if there is a possible common mode failure with FMC thrust demand control?

Skydrol Leak

19th Jan 2008, 06:54

I am not sure about that 600 feet on 2 mile final???????
That seems really low from the get go.No?

Kapitanleutnant

19th Jan 2008, 06:57

Skydrol...

That's the perfect 3 degree Glide Slope and is the standard around the world. There are some a bit more and some a bit less, but that 3 degree glide slope is standard.

3 Degrees at 2 miles (3x2 and add the zero's) is 600 ft!!

K

Ex Cargo Clown

19th Jan 2008, 07:00

Nope it is the correct altitude on a 3 degree slope.

Do the trig

2 miles is approx 10560 feet

10560 * tan 3 = 552 ft

Little bit more complicated than this, but that is the idea.

sevenstrokeroll

19th Jan 2008, 07:06

lost in saigon...

there is no indication published that the engines were at "approach setting" at six hundred feet.

pratt and whitney jt8d, cfm 56 among others, it is a company wide procedure.

try it, you'll like it.

NSEU

19th Jan 2008, 07:08

...and if we're talking two Nautical Miles along the surface of the earth (using tan as an operator), on a 3 degree glidepath, it puts the aircraft at about 637feet.

HEATHROW DIRECTOR

19th Jan 2008, 07:19

I was always taught 318 feet per mile on a 3 degree glidepath..

NSEU

19th Jan 2008, 07:23

Wouldn't need to as the RAT would deploy for the loss of either. I have on a few occasions, observed hydraulic pressure indication from a windmilling RB211

Engineers are warned that hydraulic pressure will move control surfaces even when dry spinning an engine using the starter motor.

A 747-400 pilot has even reported getting full electrics from a windmilling engine (but that was at cruise speeds). The crew of the BA 747 which flew through volcanic ash were also getting intermittent electrics (not just Battery/Standby power). You wouldn't be getting electrics from unpowered engines windmilling at 140kts, however (assuming the 777 was approaching at around this speed)....and you would be probably getting close to losing hydraulics for flight control. However, as repeated ad nauseum... no one is saying that the engines were windmilling.

Ian W

19th Jan 2008, 07:26

"I was always taught 318 feet per mile on a 3 degree glidepath.."

If you are going to use that level of precision - then which part of the aircraft are you measuring from? :)

I always found that 300ft per mile was good enough for most purposes (and far easier to work with)

GotTheTshirt

19th Jan 2008, 07:26

The basic ( serious:)) speculation semms to point to both engines failing to respond to Autothrottle Command.
We have some technical input on the forum into the fact that both FADEC, are totally independant and with alternate sources.
The Autothrottle will vary power according to some input that is trying to maintain a specified flight path from some parameter(s). The power is constantly changing to maintain this flight path
2 questions.
1 Where is the source for the A/T and is it duplicated
2.If the A/T fails to command the crew will get a visual indication from F/D that all is not well. How long from when the A/T failed to repond and the aircraft deviates from the prescibed path would the crew realise?

FullWings

19th Jan 2008, 07:32

It was a moderately gusty day, by all reports, so as the A/P and A/T were both engaged (AAIB) the 777 would have been tracking the LOC & G/S with the engines spooling up during lulls and spooling down during gusts. Unfortunately it seems the engines "froze" at a point when they were producing less than the datum power needed to complete the approach safely in the configuration they were in (gear down, F25 or F30), leading to an inevitable undershoot.

Another factor is that as the wind backed off and reduced with decreasing height, it would lead to an effective loss of airspeed that would need to be countered by a period of above datum thrust to bring it back to near the approach reference speed. This effect is more noticeable between 1,000'AGL and the ground, e.g. at 600'.

Max Tout

19th Jan 2008, 07:35

NSEU

19th Jan 2008, 07:43

"The 2 FADECS for the engines are indeed independent but how about the autothrottle itself ? Is that perhaps a possible single point of failure ? Just asking."

The A/T really isn't an issue here. All the 777 Autothrottle does is physically move the thrust levers in the cockpit using little electric motors. The thrust levers then indepedently send electric (thrust lever angle position) signals directly to the EEC's (or "FADEC's" as you call them). As stated before, the pilots manually advanced the throttles with the same effect (none).

Hope this makes sense :}

francophile69

19th Jan 2008, 07:48

Apologies for yet another bonehead question from the SLF.
We are continually told to turn off mobile phones and laptops on landing as these can effect the aircraft systems. What systems are at risk? Presumably nothing that could have this consequence?

OverRun

19th Jan 2008, 07:50

The investigation is looking closely at the thronomister which failed when electrical power was lost, and excessive aft C of G due to waste tank overflowing on the long flight, leading to low speed handling problems and a stall.

Thronomister
The engine is managed by a dual channel FADEC system. The EEC is part of this system (the heart). The EEC controls engine systems, starts and autostarts, and T/R operation. Interruption of electrical power to either channel of the EEC causes a reset of the EEC. Interruption of power to the FADEC activates the EEC inhibit reset circuit and is intended to control spurious commands in the event of circuitry over-voltage such as lightening strikes. The fuel supply to this engine is from airplane fuel system through the engine fuel pump (two stage) to the carburettor. The pump supplies fuel to Fuel Metering Unit and servo fuel for actuators. Fuel flow transmitter and thermocouples supply fuel flow and temperature readings to cockpit via EEC. The power to the fuel pump circuit is via an independent bus. Loss of the thronomister due to electrical power loss causes the fuel pump to revert to one of four fixed settings. At low engine speed the fuel pump revert setting is idle. The electrical power loss affects many systems in the 777:

_115VAC STANDBY BUS-MAIN_
ADC LEFT POWER (34-12-01)
NAV RADIO RMI (Optional)
NAV RADIO MKR VOR LEFT (34-51-01)
NAV RADIO ADF RIGHT (can also be found on 115AC Bus #1 on some airlines)
NAV RADIO ATC LEFT (34-53-01) Optionally found on 115VAC Main Bus #3
STANDBY IGN ENG 1 (74-31-01)
STANDBY IGN ENG 2 (74-31-02)
STANDBY INSTR LIGHTS (33-11-04)
FLIGHT CONTROL ELEC 1L AC (Also known as FCE Power Supply or PSM. NAV RADIO MLS-L (Optional)
EFIS CONT LEFT (31-61-01)
UPPER EICAS (31-61-01)
THRONOMISTER FUEL ENG 1 (79-31-01)
THRONOMISTER FUEL ENG 2 (79-31-02)
EIU LEFT (31-61-01)
FLIGHT CONTROL ELEC 2L AC (Also known as FCE Power Supply or PSM. One of four. See Notes)
MAWEA POWER A (31-51-01) Modularized Avionics Warning Electronics Assembly power supply A.
FMCS CDU-LEFT (34-61-01)
MAIN AC STBY BUS VOLTAGE (24-34-02)
MMR LEFT (MULTI MODE RECEIVER) 34-31-01

_115VAC STANDBY BUS- APU_
PFD-LEFT
ND-LEFT
FMCS FMC-LEFT

_28VDC APU BATTERY BUS_ (Normally supplied with DC power from TRU #3 unless forced to use APU Battery Charger or APU Battery)
ENG START AIR CONT (Provides elec power to Start Switches and Pneumatic Start Valve solenoids. Valves are electrically controlled, but pneumatically driven... They won't open without bleed air). Power for light in Start Switches comes from the #1 DC Bus.
APU DC FUEL PUMP (Required if #2 AFT MAIN BOOST PUMP is not providing pressure. APU switch must be in ON or START and the following CB's must be set: APU PRIME CONTROL (or APU ALT CTRL) and APU START)
THRONOMISTER FIRE WARN HORN (Horn located in RH Body Gear Well)
NACELLE LE ANTI-ICE 1 (30-21-01) Also known as NAI. Provides power to VALVE solenoid). Auto Anti-Ice Systems appear to use Main Bus power however
NACELLE LE ANTI-ICE 2
LOOP A FIRE 1 OVERHEAT 2
LOOP A FIRE 2 OVERHEAT 1
LOOP B FIRE 1 OVERHEAT 2
LOOP B FIRE 2 OVERHEAT 1
FIRE DET APU LOOP A
FIRE DET APU LOOP B
ENG 1 SPEED SENSOR 1 (77-12-05) Provides power to engine #1 "N2 speed card" Channel 1. N2 > 50%, N2 > 52%, N2>83% data is used for airplane system logic.)
ENG 1 SPEED SENSOR 2 (As above, Channel 2))
ENG 2 SPEED SENSOR 1
ENG 2 SPEED SENSOR 2
EEC CH A RESET/INHIBIT 1 (73-21-15) EEC Hardware reset
EEC CH A RESET/INHIBIT 2

Excessive aft CofG

The original design of the 777 was for the A market: 7,200 to 9,630 km range. When the longer range versions were introduced, the potable water system and lavatory waste system capacities were increased by an additional 383 litres of potable water, and 513 litres of waste-tank capacity. The larger tanks are located in the rear cargo compartment area and have reduced the available rearmost cargo area to 9.77 m3. This is offset by increases in forward and aft cargo compartment capacity. The original tank was 33 metres aft of the nose. With the extended range 777, the new toilet tank is 55 metres aft of the nose. The effect of this larger tank and more rear location on the centre of gravity is significant.

On very long flights (such as China-London), as the toilet is used over time, the tank overfills and spills, and the CofG can go outside the aft limit. In cruise, operating near the aft CG limit, the download on the tail is minimized and angles of attack and drag are reduced which improves performance. However, moving the CG aft reduces the longitudinal static stability of the airplane. At low speeds, at the end of a very long flight when the waste tank is over full, waste has spilt into the rear cargo area, and the CofG is outside aft limits, the aircraft is difficult to control and is tail heavy; it is more likely to stall at very low speeds.

This had been a problem before, and the incident affecting Boeing 777-236, G-VIIC, in the cruise between Barbados and London. Approximately ten and a half hours into a scheduled flight from Barbados to London, a crew member noticed an unusual odour in the cabin. Two minutes later a toilet smoke warning sounded and smoke was seen emanating from beneath the door of toilet 'N'; located by the R4 door. Fire fighting equipment was gathered and the toilet door was partially opened revealing flames and smoke. A BCF fire extinguisher was discharged into the toilet compartment and the door closed. When the fire was confirmed as extinguished, the area was investigated. The source of the fire was found to be overflowing of the waste transfer pump due to the waste tank being too full and an electrical short circuit causing the fire.

Boeing have just issued a service letter 777-SL-38-009 which requires that for Boeing 777s after 8 hours flight duration, all the economy toilets except one for emergency use should be closed off to prevent overflowing until changes to the waste tankage system can be made.

alph2z

19th Jan 2008, 07:52

Transcribed the following from Jay Leno's Friday night monologue and closed caption: Not my errors.

And yesterday they had a big crash landing in London with a 747, lucky nobody was killed but, you know I heard a guy from the FDA say that's not good enough for us, we're not gonna rest until we've reached our goal of 0 plane crashes, that's our goal 0 plane crashes, and everybody applauds......

Well of course 0 is the goal.

What are you gonna say ?? We just want 1 big crash a year, that's all we want, give us 1 huge crash and were fine.

.

pasoundman

19th Jan 2008, 07:57

" "The 2 FADECS for the engines are indeed independent but how about the autothrottle itself ? Is that perhaps a possible single point of failure ? Just asking."

The A/T really isn't an issue here. All the 777 Autothrottle does is physically move the thrust levers in the cockpit using little electric motors. The thrust levers then indepedently send electric (thrust lever angle position) signals directly to the EEC's (or "FADEC's" as you call them). As stated before, the pilots manually advanced the throttles with the same effect (none).

Hope this makes sense "

Yes that makes perfect sense (I understand what you say exactly) but that then means TWO independent engines with independent FADEC controllers and independent power sources failed to respond correctly simultaneously.

That's DEEPLY worrying.

So the A/T's control over the thrust levers is purely mechanical ONLY ? Like the cruise control in some cars where it physically 'presses the accelerator' for you.

pasoundman

19th Jan 2008, 08:02

" Apologies for yet another bonehead question from the SLF.
We are continually told to turn off mobile phones and laptops on landing as these can effect the aircraft systems. "

More to the point, it affects the profitability of existing in-flight telephones.

The idea that cellphones interfere with the avionics is AFAIK totally unproven. However it's never been totally proven that they couldn't either.

However plans to introduce 'approved' systems for inflight cellphone use suggest that it's largely not a real concern.

straightfeed

19th Jan 2008, 08:03

You know what-

Despite the possibility of crew error (they are a team after all), design fault,build fault, operational issues, training error or maintenance issues what the pilots did was just what good ole' Bob Hoover said-

They flew her all the way into the crash and walked away from it. Thats great skill.

That Boeing lump sure is strong!

Mr HF

19th Jan 2008, 08:04

:DGood thinking! If they didn't monitor the approach and sloppy respond to disconnect and execute manual go-around,well time will tell!

2.Total power loss due to birdstrikes at final,may be a neutral way of closing the case,but if they really had engine computer problems..and were unable to disconnect and execute a manual go-around.....well
BA and Boeing would come out with a statment of maybe CAT1 manual landings,but as that has not happen yet makes you think that maybe there was a technical error followed by humanerror.(like always)

NSEU

19th Jan 2008, 08:12

The investigation is looking closely at the thronomister

LMAO...

But wouldn't the piezo-electric dithermotor come askew on the threadle and offset this effect?

gas path

19th Jan 2008, 08:18

OverRun ....GET LOST:mad: You're wasting bandwidth with all that crap!

NSEU don't waste your time on him mate!

listria

19th Jan 2008, 08:22

I realise the flight crew must have been busy in the last few moments of the approach,but if they were 'expecting' a crash landing perhaps it would have been a good idea to suggest the pax get in the brace position.By all accounts the pax thought it was a normal bumpy landing.

FullWings

19th Jan 2008, 08:26

As someone who is due to fly today on a B777 (not BA) I am interested in the following:
The fact that the crew have been publicly exposed to the media would indicate that there is no question of operator error as an immediate cause of this accident. This means that, presumably, a system failure is still a possibility. In this case I am wondering why B777s are still being permitted to fly whilst there is any doubt as to the actual cause.
A good question. AFAIK, the "authorities" look at the severity of a failure but also the probability of it recurring. As the 777 has been flying for over a decade with nothing like this (simultaneous failure of two supposedly separate systems) being reported, they probably take the view that it is unlikely to happen again in the time it takes to do a more detailed investigation (a month, maybe).

There are inevitable commercial aspects: there is no such thing as complete safety, only a probability of success (or failure); grounding every 777 in the world (I believe 6-700 are flying now) might not produce a justifiable increase in flight safety, just major inconvenience and financial loss to airlines and their customers.

manrow

19th Jan 2008, 08:26

I sympathise with those posting how irritated they are by the non-technical speculating on these message boards; however to some extent it is an easy way for us to learn how the systems operate. For me, the 'need to know' philosophy for new aircraft types is inadequate and I have spent hours talking to engineers for explanations.

The real irritation for me though are the posts by journalists notably from the tabloids who blatantly advertise their publications on here with no interest in knowing the truth as that is not sufficiently news-worthy. What this incident has highlighted is how unreliable are most journalists, since exaggeration is preferable to delaying saying anything until true facts are known. That is different from pilots wanting clues on what happened to expand their knowledge of an incident which most of us have never had to face YET!

manrow

19th Jan 2008, 08:33

listria

I am sure your suggestion seems logical to you. But I would suggest that any deviation in attention by the flight crew from the absolute priority in getting the aircraft on the ground might have resulted in the brace position being necessary because they could have missed something vital to achieve their desire of a 'safe' arrival?

pasoundman

19th Jan 2008, 08:35

Just another little snippet.

Reading the AAIB press-release, I noticed they mentioned they also have the data from the Quick Access Recorder.

Is this fitted to ALL BA planes ? I know they started using them on the Trident way back. What data does it record ?

Joetom

19th Jan 2008, 08:36

Did the Fuel Metering Unit/Valve Resolvers on the Engine/s Respond to the Throttle Resolvers in the Flight Deck?

StopStart

19th Jan 2008, 08:38

Probably not much time, lots to do before that - remember the old adage:

Aviate, Ruminate, Cogitate, Altercate, Navigate, Deliberate, Anticipate, Prestidigitate, Communicate, Celebrate, Defenestrate.

I think thats how it goes.

:hmm:

Best theory I've heard so far is that ECM on the Prime Minister's motorcade interfered with the aircraft systems. I wonder though, is all this speculation just so that when the cause is revealed someone can say "I told you so!"?

Keep up the good work :ok:

Contacttower

19th Jan 2008, 08:39

There are inevitable commercial aspects: there is no such thing as complete safety, only a probability of success (or failure); grounding every 777 in the world (I believe 6-700 are flying now) might not produce a justifiable increase in flight safety, just major inconvenience and financial loss to airlines and their customers.

A lot of the 'experts' being interviewed on TV after the crash said that if there was any doubt about the 777's safety then it would have been grounded. But that isn't really true...I mean for a long time the FAA didn't ground the DC10 despite early problems (admittedly they did ground them eventually for a short period) and arguably the 737 should have been grounded after two instances of rudder hard over. So there could be a fault lurking in that plane....the engines are meant to be completely independent.

Going Boeing

19th Jan 2008, 08:40

pasoundman
The idea that cellphones interfere with the avionics is AFAIK totally unproven. However it's never been totally proven that they couldn't either.

Aircraft electrical systems are well shielded during manufacture, but the possibility of the shielding becoming degraded during airline operations/maintenance means that it is prudent to ensure that phones are not radiating during critical phases of flight.

However plans to introduce 'approved' systems for inflight cellphone use suggest that it's largely not a real concern.

There are systems being tested on some aircraft that will permit the use of mobile phones in flight. The key element of these systems is that they command all the mobiles on the aircraft to use their lowest power setting. Without this, the mobiles would step up to their highest power setting in an attempt to find a ground station and thus could get to the level where interference could become an issue - especially when there are many phones in operation. When I was in a holding pattern. I experienced autopilot fluctuations soon after advising the pax that there would be a delay of about 20 mins. Cabin Crew reported later that they had found several pax using their phones after that PA.

Apologies for the thread drift and I like many out there eagerly await the outcome of the investigation.

listria

19th Jan 2008, 08:42

Seems reasonable Manrow,it's impossible to put oneself in those guys position,no wonder the copilot looked so shocked at the press conference-they are probably stating to feel the effects of the high stress just about now-concentration must have been immense.

gas path

19th Jan 2008, 08:42

Did the Fuel Metering Unit/Valve Resolvers on the Engine/s Respond to the Throttle Resolvers in the Flight Deck?
Yes I believe they did.

Dropp the Pilot

19th Jan 2008, 08:47

China has a $2,000,000,0000 a year industry making fakes. Lest you think this is just the odd Rolex or Gucci bag for a laugh the China PLC inventory includes millions of fake parts not caring one whit how many people are killed thereby. More sinister is the the fake pharmaceuticals which often are not simply benign white chalk pills but random chemicals found out back in the garage, once again not caring one whit who or how many die.

In the case at hand the only other remotely possible explanations are a multiple bird strike of epic proportions or fuel exhaustion. Give credence to the former if you like, to the latter, well, you will need a lower opinion of BA aircrew than is common.

No, someone will have passed off a few million litres of doctored diesel fuel as jet fuel. This fake fuel of course is not tested for fuel freezing. Fuel freezing will then have occurred during the lengthy flight from China (not ice formation, but wax components of the fuel reverting to solid) and this slurry sank to the bottom of the tanks. On final with perhaps 4 tons or so sloshing around in near-as-empty tanks this fuel willl have been ingested.

Eh Voila

Have some faith in your hardware is what 10,000 hours on the 777 has taught me. There will be human skulduggery at root here somewhere.

BorderLine

19th Jan 2008, 08:56

Firstly, my apologies if this has already been covered.

To those not familiar with the 777, forget about previous Boeing product, this machine is vastly different in the way achieves the 'end result'.

From the pax reports i've seen, not one has said "the lights went out, then we hit the ground"....

Surely if there was an electrical system failure the cabin lighting would be one of the first things shed? The Pax notice that kind of thing...

The APU door is indeed open, but this doesn't mean it was running...

The RAT is shown still attached to the aircraft, surely if it had been deployed it would have been ripped clear of the fuselage on contact with the ground? The U/C was...

I know the multiple sources of electrical power availabe on the 777, Understand FADEC, AIMS and ELMS. Something is very strange here we are missing something, can't wait to hear the outcome

The fact that the 777 fleet is not grounded speaks volumes. I can't help but come back to a fuel related issue. Possibly there was more going on in flight than we know. Maybe the hero's might not be such in a few weeks time??? No offence intended to the pilots reading this.

Miraz

19th Jan 2008, 09:02

Some of the media stories and posts have been referring to electrical failure issues with the 777 - I'm guessing that they are referring to incidents like this http://www.aaib.dft.gov.uk/cms_resources/S2-2007%20N786UA.pdf

jmvives

19th Jan 2008, 09:03

Do you know another case like this, with lost all power and avionics? Thanks.

P.D.: Sorry for mi English.

lesthegringo

19th Jan 2008, 09:04

Gaspath, I am very interested to know how you believe the you know the engine FMU's responded to the throttle command. In my experience, you only can tell something like that by studying the QAR data.

As the FMU's
1) have no external moving parts and
2) would be covered by the engine fan cowls (and latterly by a few tons of earth) I'm sure that your ability to see the unviewable would be of service for many accidents.

To all those who are singling out the engines for sole fault on the basis that both failed simultaneously, I invite you to remember that the the item that links both engines and their control is the airframe and the flight control electronics.

When two engines 'fail' simultaneously, the cause is very likely to be external to the engine.

Cater

19th Jan 2008, 09:04

Has the aircraft now been moved saw the cranes around it last night but no pictures on any of the news sites this morning

Joetom

19th Jan 2008, 09:05

Quote:
Did the Fuel Metering Unit/Valve Resolvers on the Engine/s Respond to the Throttle Resolvers in the Flight Deck?

Yes I believe they did.

Thanks Gaspath.....

Any idea of Fuel Quality Checks carried out from Fuel on Aircraft?

NSEU

19th Jan 2008, 09:05

Reports seem to suggest that all electrical power was lost and the cockpit avionics went dead.

Most of these reports are based on idle speculation, hearsay.. and dare I say it.. PPRumour...

ALL electrical power would NOT be lost, even if the engines died, the RAT and APU did not start up... and the wings fell off. This is what Battery & Standby Power is for ... and generates sufficient power for dozens of systems to operate (including instruments)

The open APU inlet door suggested that the APU may have tried to autostart due to loss of main bus power, but with most of the fuselage fairly intact, it may have even tried to start AFTER crashing.

radiosutch

19th Jan 2008, 09:07

Slightly off subject, but having read comments from passengers on how they were treated by ground staff I want to ask what basis BA have for keeping passesngers virtually under arrest? Seems to me they want to stop passengers speaking to the media more than anything.
Accepted there is immigration and customs, but heard similar stories before on domestic.
If I were an uninjured survivor I suspect I would go and tell them to get the police and formally arrest me otherwise I'm off!!. What powers do they have to detain?

Good show in the air BA, less so on the ground.

212man

19th Jan 2008, 09:08

Prof overun, why don't you go back to your Flightsim forums?
http://nzff.org/forum/index.php?act=Search&CODE=show&searchid=6ba339ffc2cc90e98fe294a0c6d79548&search_in=posts&result_type=posts&highlite=%2Bthronomister

Carburettors? Give me a break:ugh::ugh::ugh::ugh:

Super VC-10

19th Jan 2008, 09:08

The AAIB report says "2 miles", can someone confirm this means 2 nautical miles (3.7km) and not 2 statute miles (3.2km)?

Well done to all involved. :D Aircraft are replaceable, people aren't.

WindSheer

19th Jan 2008, 09:10

Is anyone like me getting the hint that this sounds more like a complete loss of electrics and systems, rather than a dual failure?? Maybe the engines were indeed idling all the way in and were not responding to any demands.
If this was the case the residual thrust could have been a saver, and gave just enough to get it over the fence....:confused:

Anyway, what does my speculation matter...!!!

More to the point will the BBC PLEASE PLEASE PLEASE get someone who knows a slad tad of anything about aviation to head their broadcasts on this matter......."..apparently the Captains number 2 was flying the airplane in, something that is apparently quite normal.."..........:mad:

A310BCAL

19th Jan 2008, 09:10

Have been drawn to PPRuNe by the recent events at LHR. As so many other "authors" have said, it was so exasperating hearing the speculation and guesswork being bandied about by the media, not to mention poor interpretation of the facts when they were finally produced yesterday.

I think the most overiding thing is that Captain Burkill and his crew did a SUPERB job in what is surely a nightmare situation. All of us that fly whether it be a B747 or a light aircraft can imagine the gut feeling when you advance those thrust levers and get no response. The sight of the runway disappearing into the distance..... what a nightmare. So I think one has to remember the old saying... "if you can walk away from it, it was a good landing"!!!.....

Well done to the whole crew for a most professional outcome!!!!:D

doubtfire

19th Jan 2008, 09:11

For those non-pilots amongst our readers and the press that still bang on about engine failure......

Imagine your driving down a long straight road in your car and there are no other vehicles about. You approach a set of traffic lights ahead which are on red. You take your foot of the accelerator pedal in order to slow down. No brakes required as your some distance to go. Now the lights turn green and so you put your foot down on the accelerator pedal but you do not speed up or even maintain the same speed. The car slows down. The engine is still running `cos you can hear it, but the tacho shows your engine at idle. You press the pedal again but still the engine fails to respond. You coast to a stop 100ft short of the traffic lights. Other than getting out and pushing there is no way you can make it to the lights.
You call out the AA and he tells you your throttle cable has snapped.

THe AAIB said nothing about engine failure. Just a failure to respond.

Now I know bugger all about triple 7`s but if they`ve got the equivalant of a throttle cable thats common to to cruise control and the accelerator....then thats not a bad place to start looking.

Obviously my theory is blown apart if the supposition that they were cda all the way down to spooling up at config full, gear down and vref at 600ft is not the case.

Crromwellman

19th Jan 2008, 09:15

As an ex-PPL of very low hours I will not speculate on the cause of this incident. I will leave that to the experts of the AAIB and other competent organisations.

As to why there was no Mayday call or cabin PA announcements, I remember my CFI telling me that when confronted with an emergency the first thing was to FTFA (Fly The F:mad: Aeroplane). IMHO any emergency at 600 ft requires total concentration on flying the aeroplane and perhaps in dealing with the emergency in hand the lower priority matters of Mayday calls and cabin PA announcements got put on the back burner.

All I can say to the flight-deck crew is congratulations on the execution of a fine piece of that old-fashioned thing - Airmanship and to the cabin crew congratulations on a well organised and professional evacuation.

gas path

19th Jan 2008, 09:16

OK lesthegringo I'll rephrase that to 'I'm led to believe that the FMU's followed commanded position'
read into that what you will;) However it will all come out in the wash:ok:

wilsr

19th Jan 2008, 09:20

And how about if the engines never went up to flight idle, or were never signalled to spool up? It's all pure speculation until more facts come in - and it may be quite a while before they do, given the complexity of the modern systems.

The Messiah

19th Jan 2008, 09:22

wilsr do you mean approach idle?

Joetom

19th Jan 2008, 09:24

Sounds like too little time to tell the Cabin Crew.

Had the Cabin Crew and Passengers been aware of what was to come I would guess more people would have got hurt.

All in all, a super result to a big problem, well done to all....:ok::ok::ok:

WhoFlungDung

19th Jan 2008, 09:26

A modern long range twin engine ETOPS approved aircraft experiences an unexplained "situation" where thrust is suddenly not available from either engine.

Am I the only one that has some serious concerns? Wouldn't it be appropriate to ground or limit the type until a plausable explanation can be offered?

listria

19th Jan 2008, 09:29

Whoflung!Safety has its roots in the deep dung of cash....

patrick murphy 1

19th Jan 2008, 09:31

It's some time since I was operating LHR but I wonder - is the 777 that clean you can control speed at the '160 till 4' (160 kt till 4 nm) that someone raised earlier, with flap/gear selections only? I would have ASSUMED the engines would have been used somewhere, especially in the reported gusty conditions, and then throttled back to reduce to target threshold speed from 4 miles....

In direct comment on ILoadMyself's post - I do think you could have been just a leeetle bit kinder in your comment on the demeanour of the Cabin Services Director (..."with orders not to look the least bit happy" was how you put it) while on TV, shortly after a VERY fraught experience. Ever heard of Post Traumatic Stress??

Murphy's Law(yer) will be busy!

frangatang

19th Jan 2008, 09:31

The aircraft should have been fully configured at 1000 ft including power at approach setting and on the glideslope. At 500 ft they have to have been fully stable or gone around. So,if at 600 ft those thrust levers were at around approach setting and a little increase was demanded for whatever reason , then even if nothing happened they would surely have landed a lot deeper thanjust inside the perimeter fence. If the engines were at idle at 600 ft(and that is only an if),then the aircraft would not have been stable at 500ft in any sense.
Glad it was 27L as 27R has no luxury of plenty of grass inside the fence,and a multi storey car park just outside.

BorderLine

19th Jan 2008, 09:32

Lets face it, we are all speculating about WHAT HAPPENED, something the investigators already know. The DFDR etc will have shown that. Meanwhile they are teasing us, while they work out WHY. Soooooo unfair!

HerrFlick

19th Jan 2008, 09:46

Digitalsubstance what on earth makes you think this was pilot error with only speculation to go on?
However Frangatang you make a valid point. the aircraft I fly needs approx 1.3EPR on a normal approach, if it was at idle as you correctly say the approach was not stable.
we of course have to wait and see.

Teal

19th Jan 2008, 09:47

The Chinese fuel contamination suggested by Dropp the Pilot has to be high on the list of possible causes. (It also supports my earlier theory of contaminated or blocked fuel nozzles for the same reason...:)). It can and does sometimes happen - ask Mobil Oil Australia

http://www.aph.gov.au/library/pubs/chron/2000-01/01chr02.htm

Eboy

19th Jan 2008, 09:48

"Imagine if you would, a businessman or woman anxious to get their messages after a long transcontinental flight. To save a few minutes they turn on their cellphone while on final appraoch knowing that they will be able to get a signal at that point . . .."

This has been mentioned a couple of times recently in posts. I just want to add as SLF that I increasingly observe wireless devices being turned on during final approach. SLF may not be talking or texting but the devices are being turned on and transmitting control signals, I expect at high power to get a signal through those small windows to a base station antenna that is designed to have low gain above the horizontal (geometrical) plane.

Normally I expect this is not a problem. But (also suggested above) if some shielding comes loose from a cable, a filter breaks, etc. perhaps the system could become susceptible.

The SLF's wireless service providers store accurate, to the second, records of access that could be checked and matched to the sequence of events. Be aware, though, that it is possible a wireless device was attempting a contact at high power but did not succeed with the base station. In that case there would be no record.

120.4

19th Jan 2008, 09:49

Recently ex-LL approach ATCO here. I wonder if a B777 qualified person would give me a considered opinion on a hypothetical point.

I understand the aircraft had 151 people on board against a full load of about 320? I would estimate that another 150 or so people and their luggage would weigh in the order of 15 tonnes? Had the aircraft been operating at full load it would obviously have had a higher final approach speed. My question:

Is it likely that at such a weight it would still have been able to glide to the field? In other words, did it only just make the field because it was relatively light or would the higher final approach speed have carried it in at the heavier weight?

.4

NSEU

19th Jan 2008, 09:49

Forget about approach/flight idle.. The engines are not going to be at idle on a 3 degree glidepath with landing flaps and gear hanging out (The captain said it was a normal approach until 2 miles out). You need thrust to maintain a 3 degree glidepath.

If the engines were at any sort of idle, then something has failed...

arse

19th Jan 2008, 09:54

Would it be possible that the aircraft suffered a single engine failure at 600 FT and then the engine failure procedure was rushed and the incorrect engine shut down? If that was the case, then I doubt they would have had time to get it going again!

This has happened in other accidents/incidents!

Sorry if this has already been covered. I haven't read all 32 pages!

backofthedrag

19th Jan 2008, 09:54

Should the AAIB discover ( or in fact have already discovered ) fuel contamination or excess water in the fuel , attributable to the Chinese end of the operation , will there be political pressure to avoid a diplomatic faux pas during the Prime Minister's visit to China ?
All pure speculation and rumour .

Howard Hughes

19th Jan 2008, 09:54

Having finally read through the entire 32 pages of this thread (in between server crashes), the two following comments stand out to me above all others!
One question, does anyone else share my unease about heaping praise on the crew until the full results are in, I seem to remember something similar regarding Kegworth for the first three days after that incident.
I certainly do share your unease! I don't understand how we can be praising the crew (apart from the cabin crew who initiated the evacuation) unless we know all the factors that contributed to this accident! Sure the outcome was favourable on this occasion, but that could just as well have been 'in spite of' the crews actions', rather than 'because' of the crews actions'!

Now this is not to cast aspersions on the crew, but to say perhaps we should hold off on the praise until a little later.

At the moment all we have is speculation, albeit some well informed! I too have my own theory, but for the time being I will keep it to myself, let the investigators do there job people!
Have some faith in your hardware is what 10,000 hours on the 777 has taught me. There will be human skulduggery at root here somewhere.
I too have no doubt that there will be a human element involved, I just hope that it is neither a deliberate, nor negligent involvement...

Rick Studder

19th Jan 2008, 09:57

Higher speed/weight would make no difference. They cancel eatch other out, so to speak, and the gliding distance would be the same.

Danny

19th Jan 2008, 10:01

I'm in a hurry to get to LHR to go to work so apologies for the methodology of getting this message across but here goes:

Mods: PLEASE FEEL FREE TO ANNOTATE THOSE POSTS THAT ARE SO TOTALLY TIME WASTING FROM PRETENDERS WHO USE FLAWED TERMINOLOGY TO TRY AND PRETEND THAT THEY ACTUALLY KNOW WHAT THEY ARE ON ABOUT. I SUGGEST LARGE RED WRITING UNDERNEATH THEIR POSTS WITH ANALOGIES COMPARING THE POSTERS TO "WALTER MITTY", "FLIGHT SIM DIPSTICK" AND "BLITHERING IDIOT"!

IT IS ABSOLUTELY STAGGERING THAT SOME OF THE POSTERS ON THIS THREAD COME UP WITH IGNORANT, UNEDUCATED AND TIME WASTING COMMENTS THAT WE MODS THEN HAVE TO SIFT THROUGH IN ORDER TO TRY AND KEEP SOME SEMBLANCE OF REALITY TO THE CONTENT. THE MODS ARE FREE TO FIRE AT WILL AT THE REGULARS WHO ARE TRYING OUR PATIENCE AND FLOODING THIS THREAD WITH NINCOMPOOP THEORIES BASED ON THEIR LACK OF ANY RELEVANT EXPERIENCE APART FROM AN INTEREST IN AVIATION AND HAVING BEEN A PASSENGER ONCE OR TWICE!

THE TIME HAS COME TO NAME AND SHAME THESE TIME WASTERS WHO ARE TRYING OUR PATIENCE WITH THEIR ILL INFORMED BRAVADO AND NONSENSE. YOU HAVE BEEN WARNED!

TheChitterneFlyer

19th Jan 2008, 10:01

And the speculation continues...

I feel sure that everyone has read every sentence and paragraph within the media press reports and it's my hope that every professional flyer will agree that it's all been a huge pile of 'tosh'. The 'Chief Editor' of the Daily Mail drivelled on and on about how many holidays the captain took etc, and I'm very surprised that we didn't get his inside leg measurement included into the 'hogwash' of a press release.

We've had many speculators and so called 'professionals' putting in their two-penneth into this thread, which I feel has fuelled the rubbish that the press have fed into their press reports. PPrune is a fabulous tool, but there are many people who have added a comment here just because they can, but really don't have a clue about what they are talking about :ugh:. There's no point in having free speech from Joe Public about matters that they are clearly inadequately prepared for... it will only fuel the rubbish that the press will inevitably quote as being from a reliable source!

Wings have fallen off... no PA from the captain... APU door open... RAT deployment... lights still on in the cabin when power failure was reported, etc, etc, etc. Come on guys get real; it all happened in the final couple of miles and at around 600 feet; who in there right mind would think that a RAT is going to adequately spin-up at 140 kts or so? Who cares? Lights still on in the cabin... it's called Emergency Lighting! These guys didn't have any alternatives in their back pockets and they could do nothing more but stetch the glide and try and put the aeroplane into an open space... hence, very high 'Alpha' and low over the fence at low speed; vis-a-vie, huge carrumph and shove the gear up through the wing root. John Coward did a good job; as did the Captain and the cabin crew :D... it's called a team! Let's leave the investigation to the AAIB and wait for the real facts.

I've now had my two-penneth; without any speculation! I prefer to leave that sort of thing to the professional guys who are trained to do that very job; Robin Tydeman... former Test Pilot, Airline Captain and now Accident Investigation Officer.

For those who want to 'have a go' at me from behind the cover of their laptops... please feel free to do so; I'll reply to the professionals, but to those who have reported wings falling off and why the lights were on in the cabin; captains holidays and inside leg measurements... I have an ignore button!

TCF

Edit
Well said Danny... you got yours in whilst I was being tested by the loss of bandwidth.

jet999

19th Jan 2008, 10:06

Well what a lot has been said. True the APU may have attempted to start as both transfer busses became unpowered during the ground run. LHR regularly requires 160 to 4 nm. When flap 30 bites, engines will auto spool up to maintain speed. However the 20 knot difference on a light -200 means that there will be some time before engines are commanded back from towards idle. 777 autothottle is somewhat slower to respond than the 747-400. BA require stabilised approach from 1000ft AAL, but this is not always possible with 160kts to 4nm unless you anticipate the 4nm point. If you decelrate at 4nm, then you won't be stable at 1000 feet. Just perhaps the stabilisation was later...it may have saved the day.

Quite how BA persuaded the pilots to be paraded on TV is beyond me, I would never do this. You can be sure they are certain there is no pilot error if they do this. A very good job done by all faced with this nightmare.

I too have some deep concerns of how an apparant double power down short finals ahs not grabbed more airlines deep attention. There have been a few reported cases of relay/ electronic control panels overheating in the last 5 months, all on the ground.
Looking forward to final report. Meantime well done chaps, and don't talk to the press remember the rules....
Rule 1 Never talk to the press- it NEVER works in your favour.
Rule 2 If tempted to talk to the press, see rule 1.
:ok:

Howard Hughes

19th Jan 2008, 10:12

You can be sure they are certain there is no pilot error if they do this.
All you can be sure of, is that the BA public relations team are in full swing!:rolleyes:

DISCOKID

19th Jan 2008, 10:13

today's guardian today is quoting the following 'facts' from an unnamed source on the investigation...

- engine pressure ratio gauge had failed
- APU was deployed
- Thrust levers were on maximum setting

http://www.guardian.co.uk/transport/Story/0,,2243357,00.html

rubik101

19th Jan 2008, 10:23

If, as many posters have postulated, there was a major lack of response to the demand for power at or around 600', then pray tell me just what input the pilots had on the eventual outcome? They were as much passengers as the rest of the people on board.
If throttles/power levers fully forward and full aft elevator are not found to be the position at impact, I will be most surprised.
The pilot of the Iberia bounced landing in Bilbao is reviled and ridiculed with scorn, described as an amateur and badly trained. Now, in a far worse outcome, we have posters heaping praise on the crew of BA038. How silly will you all feel if the AAIB find the crew cocked up the whole thing?
While I am not suggesting this is the case here, please, until we know exactly what happened, can we try to refrain from handing out medals and signing off on the subsequent board of inquiry?

mocoman

19th Jan 2008, 10:33

today's guardian

Not sure how much I trust the Grauniad; well at least their copy-editors and proof-readers.

Those same articles contain the following statement:

"...there has not been a single fatality on a 'major' airline for more than seven years. The last such crash was....in November 2001"

Better get those adding machines out there guys. :hmm:

pb365

19th Jan 2008, 10:33

Discokid,
I would be very wary of most if not all newspaper items. All too often they are written in general terms by people who little or no knowledge of the subject at hand.

I am a non-aviation person but here's my two-pence worth and I emphasize it is a guess so perhaps a professional will be kind enough to comment.
I wonder if this could point to a software failure? All software has bugs and one worrying statement I have heard is that sometimes a bug will take years to materialize.

For the present we do not know and and inquiries may even reveal an event that has not happened before. Such a situation or situations are one reason to maintain a human presence on the flight deck.

I suggest we all stay patient and wait until facts are established, too many here and elsewhere are believing rumours and theories, the facts are much less entertaining.

stickyb

19th Jan 2008, 10:34

There have been suggestions that cellphones could contribute towards electrical systems upset. I have no idea if that is true or not, but one area I have a lot of experience (much more than any of you professional pilots) is flying in the back as SLF, especially around Asia and in China.

The point I would make (without wishing to be xenophobic) is that on many many flights I hear cell phones beeping or ringing on the last stages of approach, and some pax even carry on conversations. Some arlines make no attempt to stop this at all, and it is difficult for the CC to monitor as they are by that stage of the flight usually strapped in themselves.

Again, not putting this forward as any suggestion of cause. just noting the occurrence on Asian flights

anotherthing

19th Jan 2008, 10:34

Rubik101

I agree with you, but as I am sure you are aware, although the Moderators detest speculation from 'timewasters' et al, if that speculation 'states' that the crew were heroic and averted a disaster, it is accepted.

I personally doubt it was aircrew error, but at the same time, I doubt very much whether the flight crew had much input to the outcome. People on these forums (the professionals), decry newspapers for writing the usual "fought heroically with the controls, narrowly avoiding a nunnery/school/orphanage" whenever there is an incident, but then sit back and do it themselves on this forum!

Some of the 'professionals' who post on here speculate as much as the media :ugh:

allan908

19th Jan 2008, 10:38

Well, a huge number of posts causing the server to crash almost as badly as the subject. The themes seem to be:

1. “I’m only SLF but it seems to me……”

2. “What about the digital whatsit thingummyjig which is on the doolally whosit which COULD have failed….”

3. “I’m a fully qualified 777 capt and we should not be commenting on this until the AAIB report is in”

4. “Stop the weenies commenting. Wait for the report. Full praise to the crew”

5. “Fuel”

6. ”Crew error”

7.“RR must be worried”

8. “The mods are not happy”

For new viewers this represents the previous 365 pages……now read on….!

PS. Don’t speculate, wait for the report, well done the crew (flight deck and cabin)! {No 4} :E

Locked door

19th Jan 2008, 10:39

rubik101

I suspect you don't fly.

The flight crew were way more than just passengers. The only reason all on board survived is that the aircraft reached the ground wings level. If you want to see what happens when the wings aren't level at touchdown watch the video of the hijacked Ethiopian 767 that ditches.

From finding out they had no thrust the handling pilot used all the knietic and potential energy they had to reach the field, maintaining good forward speed until well into ground effect whilst not allowing the aircraft to stall until very very close to terra firms (if indeed it stalled at all). Had a wing been allowed to drop (ie stall due to low speed) even at 100ft the results would have been very different.

Awesome job well done

LD

aviate1138

19th Jan 2008, 10:42

We can relax now as I see in the Mail that the Captain's wife is negotiating with Max Clifford to sell the Captain's story to the Media!

I would hope that was not a joint family decision?

Where is that old 'stiff upper lip' going to?

Clandestino

19th Jan 2008, 10:43

Well, if you're too lazy to read the whole AAIB initial report, here's the most salient part of it:

Initial indications from the interviews and Flight Recorder analyses show the flight and approach to have progressed normally until the aircraft was established on late finals for Runway 27L. At approximately 600 ft and 2 miles from touch down, the Autothrottle demanded an increase in thrust from the two engines but the engines did not respond. 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.

So can we please put all speculations about this being another Kegworth to rest, pleeeeeease.

Also anyone who suggests that approach should be stabilized by 1000 AGL, with power and speed IAW final approach settings, or that you need engine out of approach idle to fly 3° glidepath, has not actually flown into Heathrow, or for that matter any other major European airport for at least last seven years (and probably more). Due to noise abaitment and traffic sequencing requirements, approaches at LHR are flown with intermediate flaps, gear retracted and 160 kt untill four DME. At 4 miles out, gear goes down, flaps goes towards landing setting and as you need to decelarete towards Vapp, engines go to flight idle. Depending on your weight and prevailing wind, you'll be fully established (speed, power, config) between 900 and 500 ft AGL and it seems that this was the point where first signs of trouble became apparent. Less than a minute later, airplane hit the dirt. Congrats to the crew, whatever they did, they've kept the airplane upright untill the ground contact and that's not a small thing.

ILS27LEFT

19th Jan 2008, 10:48

...contaminated fuel, maybe just water left: this could explain why the ultrasonic sensors signalled sufficient fuel in tank?
I cannot think of anything else for now.

A lesson: all runways should be like 27Left from now on. This incident could happen again. Same incident on 27 right at EGLL and the 777 would have found the VS Car Park. Slightly harder than the wet grass. RESA needed.
Let's move these car parks.
:mad:

Well done to the crew, and maybe to the 777 autolanding system(!). Just kidding.

tbaylx

19th Jan 2008, 10:54

To those who suggested an engine failure and the crew shutting down the wrong engine.

First the B777 EICAS and company SOP's makes that pretty difficult, second no proffesional airline crew is going to do anything with an engine 600' above the ground on short final except continue the approach and deal with it on the ground.

For anyone suggesting that the crew had time to transfer control, troubleshoot the issue or generally do anything other than fly the aircraft obviously doesn't appreciate just how little time you'd have to recognize and respond to an abnormal situation that close to ground. The crew did exactly what they should have in that situation, jam the thrust forward, say WTF? and maintain level wings and do whatever you can to make the field without stalling the aircraft and making it worse.

Lastly they are not going to ground the worldwide fleet of B777's that have completed millions of trouble free hours for an incident that they don't even know the cause of yet. Should it be proven to be an aircraft/engine/software issue then i'm sure we'll see the AD come out fairly quickly.

In the meantime lets let the investigation team do their jobs and figure out what happened. Best thing you can do in the meantime is close your mouth and not make yourself look any stupider by coming up with outrageous theories on a subject many of you apparently know little about.

Capt Groper

19th Jan 2008, 10:58

Sounds so far fetched it could be the answer?
:confused:

TheChitterneFlyer

19th Jan 2008, 11:06

Sandbank

It's been a while since I retired from BA but it used to be that if the FO is handling the aircraft (i.e. his sector) he will act as PIC throughout the whole flight (PICUS); Pilot In Command Under Supervision.

The Captain does indeed have every right to assume control of the aeroplane and would do so if needs be. In an incident such as this, it's my guess that it would be mighty tempting for the Captain to take over the controls; however, the ability of the FO is usually known and unless he's making a real mess of things it's best to leave him handling the aeroplane... it takes a significant period to hand-over and adjust yourself to how the aircraft is responding, so it might actually make things worse when within the final stage of the approach to assume control.

This would always be a 'command' decision. Command comes with both training and experience and you cannot always put everything into neat little boxes; therefore, the 'commander' has a huge responsibilty in making those decisions. I believe that in this particular scenario that we will discover that the FO in question isn't that far from achieving his own command; which the Captain would have known and taken into considderation at the time... that's what makes a good commander!

TCF

JenCluse

19th Jan 2008, 11:07

I'm a far too long ex-A320 P1, haven't had time to read all 33 pages (relaxing retirement? forget the idea), and really, should not comment, but a couple of questions nag at 3am.

This event recalls the fuel gauge malfunction double engine flameout in the 767 into the disused WW2 strip in Canada some years back, where both flight crew were current glider rated. They pulled off the classic out-landing beautifully, with only a bent nose oleo in the freshly dug ditch across the strip. BUT, their double failure was at height. (Cruise height rings a faint bell. Shear bluuddy lookshury.)

Q. Anyone know if these 777 lads are glider rated, or current light A/c instructors?

Reason I ask is that the reported low approach & hi alpha at touch so remind me of my ancient past, when, doing first practice forced landings onto home strip, I misjudged, and would have obviously worn the fence from an approx 80-100' undershoot. Boss said 'go round' but I said 'OK. But what if this was a real situation? What could I do?' He said 'mine' lowered the nose to gain maybe 5-6 kts from about 300', sat it (26' span Victa) in ground effect, & we watched as the speed very slowly bled off. He eased it up over the (sheep) fence and we dropped like a bag of the proverbial on the other side.

Not what I would have ever demonstrated when I got to instruct, but he made a point I never forgot, and which I at least passed on verbally.

When I went gliding, the hairy late afternoon 'I >will< get homer's' at my (flat land) club would tuck down into ground effect quite a way out, and proceed to make it.

This lad's approach seems a fairly similar example of such a technique. Comments?

The reason for the event will certainly surface, but some time in the future.

Let's be patient and kind, and especially congratulate the cabin crew on a fine following_of_procedures. Fire-ies also spot on. Excellent work all round. T.G.

HotDog

19th Jan 2008, 11:14

There was an AD issued for 777 FADEC problems , albeit with the GE90 power plant. Bears some resemblance to the subject.

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/07577b0b9213888985256930005117ca/0dd44fe2beb1f516862571f9006b5dad!OpenDocument

jet999

19th Jan 2008, 11:24

Sorry Clandestino that is not the case, whilst you may be gear up at 4nm due' noise abatement' big company regs require stabilised approach at 1000 feet AAL. Thats flap 30, landing checks done and gear locked with power stabilised. You cannot fly the profile you claim on a 777, it won't match company stabilisation criteria.
For the 777 which takes 400 feet to select gear down to locked on a 3 degree approach, and then 400 feet to go from flap 20 to flap 30, you need 800 feet minimum. You should not select flap 30 with gear still travelling as you get a config warning. So 2000 feet AAL is the BA (and other) recommended latest selection of gear and 1500 feet AAL latest flap 30 selection. Vref30 will be sigificantly below 160 kts, requiring power down and time to stabilise and then spool up for the 1000ft AAL gate.
777 autothrottle responds slowly to speed reduction commands but more quickly to speed up commands. If it needs 160kts to 4 nm, you either bust the 1000ft stabilisation point or you anticipate the speed reduction by a mile or so to achieve a decent satbilisation at 1000 ft AAL. Sesma will trigger unstable approaches and you will be called in.....

TDK mk2

19th Jan 2008, 11:24

My company SOP is to fly 160 knots to 4 miles at all airports, not just Heathrow, and then reduce thrust to flight idle in order to reduce speed below the full flap limiting speed, take full flap, then increase thrust to maintain the calculated approach speed (an increment on reference landing speed) minus 5 and plus 10 knots. This is to be stabilised at 1000 feet agl in instrument met conditions or 500 radio altimeter in visual met conditions.

So in my own operations it's quite normal to be increasing thrust to maintain that approach speed at 2 miles and if I found that there was nothing there at that point I would consider it highly unlikely that I would make the runway in most cases. And many other runways I land on do not have the clear undershoot area available that 27L at Heathrow does.

Gets you thinking about the what ifs doesn't it?! The sooner the experts at the AAIB can figure out why engine thrust didn't increase when demanded the better. But who knows, maybe they'll never know. Maybe the system of computers and wiring between those thrust levers and the engines will function perfectly when they test them. It's happened many times before with electrical systems, just have a look at the AAIB report released this week on the BA Airbus 319 over London in 2005. How many times have you powered something off and on to clear a fault?

groundfloor

19th Jan 2008, 11:30

What can we learn from this immediately? Flying the aircraft is still important....Looking out the most important instrument on the a/c (the window) is stil important. Owners, managers, trainers take note! Well done guys...Well done also to the couple of relevant posts...to the rest :uhoh:

Rick Studder

19th Jan 2008, 11:33

This lad's approach seems a fairly similar example of such a technique [gliding in ground effect]. Comments?

Whether he was consiously utilizing ground effect, who knows, but apparently the aircraft stalled about 10' above the ground. I wonder if this was what made the nose come down enough to avoid a tail strike (doesn't appear to have been one from the looks of the photos).

Whisky

19th Jan 2008, 11:33

http://i.a.cnn.net/cnn/2008/images/01/18/report.heathrow.pdf

sevenstrokeroll

19th Jan 2008, 11:47

your observations regarding the speed of the PR department are right on.

I hope the crew didn't screw up, I really do. But if so many demand we wait for the AAIB report instead of speculating, we must use the same discipline before eliminating human error.

Bronx

19th Jan 2008, 11:50

Captain Burkill is understood to have two children from a previous marriage. Last night, it emerged Mrs Burkill 34, who met her husband while she was a long-haul air hostess with BA had contacted publicist Max Clifford with plans to sell her husband's story. The publicist was understood to be in negotiations with Sunday newspapers.
:rolleyes:

reverserunlocked

19th Jan 2008, 12:00

I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK?

Launchpad McQuack

19th Jan 2008, 12:05

I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK?
Serious structual damage aside (write-off?), why would Boeing pay to repair the damage? As there has been no full AAIB report yet, we've no idea if Boeing is in any way responsible??

DX Wombat

19th Jan 2008, 12:07

I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK? I understood it was the other way round. Boeing recommended scrapping OJH but QF didn't want to lose their reputation for never having sustained a hull loss. I could be wrong.

tristar 500

19th Jan 2008, 12:09

Reverserunlocked asked

I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK?

That was a Qantas decision not Boeing. QF wanted to maintain the record of nof having had a hull loss.

Tristar 500

snowfalcon2

19th Jan 2008, 12:10

This lad's approach seems a fairly similar example of such a technique. Comments?

I would disagree. Ground effect basically starts at half a wingspan above ground, and to take a 777 THAT near the obstacles would be too close for comfort. Besides, you won't get much of a ground effect above trees and buildings, compared to a flat field.
Good observation that there apparently was no tailstrike. This may have saved the fuselage from breaking. As far as I can judge, the PF pulled up to arrest the sink rate and clear the fence, but we don't yet know if the plane came to the point of actual stall or was still steerable in pitch at the final stage. It may have been in a partial stall with high sinkrate, with AoA close or at stall angle, but deck angle small enough to avoid tailstrike. But the FDR data will tell soon.

Alwaysairbus

19th Jan 2008, 12:18

As an engineer i always found the 777 very reliable (last worked on it 8 yeras ago) other than a few software resets compared to the Airbus which throws a wobbly and can only be recovered by complete down powers, albeit on the ground.
The Trent engines other than a few sensors and thrust reverser defects are very reliable.
I would imagine the investigation will lean towards computer glitches rather than fuel contamination...for both wing tanks to be contaminated to exactly the same extent and cause simultaneous shutdowns seems vey unlikely or though a possibilty... the amount of water found in the 330 wings during weekly fuel/water drains shows exactly how much fuel/water the engines can deal with.
Well done to the pilots.

P.s the way i remember the 777, with no PFC's they were only flying on 2 spoilers and the stabiliser which if this was the case makes the landing even more remarkable.

Organic

19th Jan 2008, 12:18

It has been registered as "destroyed" on www.atdb.org which has proved fairly reliable in the 2 years I have used it.

ACARS

19th Jan 2008, 12:19

I'm just a C172 driver.

If this happened at 2nm/600ft, any pilot knows that loss of power will result in loss of speed and higher sink rate (power controls rate of decent right?)...............This means no time to alert the crew. Full credit to all. :D

paulthornton

19th Jan 2008, 12:21

There have been numerous references to them stretching the glide out in order to reach inside the field boundary in this thread - and I've been puzzling over this for the last couple of days. The site seems to be having a quieter moment so I can finally ask someone whose aerodynamic engineering is much better than mine to put me right...

I know full well that a swept-wing heavy jet is NOT a light aircraft and things handle differently, and I only have experience with the latter, but we're all taught when we do our PFLs or glide approaches in the circuit to maintain the best glide speed and emphatically told NOT to try and stretch out the glide.

Now I have no idea what the optimum glide speed is for a 777 with everything dangling out, at that weight, but isn't it fundamentally still true that you'll have the best glide ratio at the point where the induced and parasitic drag curves intersect on the speed vs drag graph? Once you get onto the back side of the curve you are surely reducing the distance you'll get to as you have more drag; so this alone wouldn't help you.

I get the whole "reduce the airspeed to reduce the kinetic energy at the time of touchdown" and that you'll want it to be stalling as it hits the ground thing, just not the glide stretching attempt. Someone put me right please!

Paul.

slink

19th Jan 2008, 12:33

By all accounts the pax thought it was a normal bumpy landing.
Which I think, that whatever the technical reasons for this accident, reflects very highly on the skill of the flight crew. With very little time to react, and sub-optimal thrust, the SFO appears to have still managed a reasonable flare to touchdown, resulting in the "heavy" landing as felt by the SLF, but not heavy enough for some to realise it was a crash!

I also think that this incident does not say very much about the strength of the 777, and comparisons to the A340 run-pen incident are meaningless. The 777 touched down in apparently the correct landing attitude (or close to it), taking the heavy landing on parts that were designed for it. One MLG punched into the wing, the other was ripped off - presumably by the additional drag afforded by the grass, which I suspect also contributed to the NLG collapse. The A340 accident was totally different.

Unless we have like-for-like data (please, no!) to compare, it is a dangerous precedent to set comparing fuselage strengths - yes, the 777 stood up well, but this is only a result of lots of factors, beginning with Boeing's design, and ending in the SFO's flare, touchdown, and rollout (although I imagine he didn't have a huge amount of options left during that phase!).

Thanks guys for the large number of factual posts - the others we can always skip over.

You Gimboid

19th Jan 2008, 12:35

For the 777 which takes 400 feet to select gear down to locked on a 3 degree approach, and then 400 feet to go from flap 20 to flap 30, you need 800 feet minimum. You should not select flap 30 with gear still travelling as you get a config warning. So 2000 feet AAL is the BA (and other) recommended latest selection of gear and 1500 feet AAL latest flap 30 selection. Vref30 will be sigificantly below 160 kts, requiring power down and time to stabilise and then spool up for the 1000ft AAL gate.

Well almost - if it helps to clarify matters, intermediate approach power settings are in the order of 55% N1 with Flap 5 selected, 180kt. With a 10kt headwind component, the 777 will happily fly a 3deg slope with Flap 15, 160kt to 4 DME. Power settings at this point will still be quite low (<40% N1 with speed stabilised). At about 2000ft RA the gear will be selected down (As jet999 correctly states, BA SOP is to have gear selected down by 2000ft RA (radio altitude=height above the ground), and configured in the stabilised approach BY 1000ft RA. The onboard flight data monitoring system (called SESMA) will trigger any significant divergence from these criteria.) Flap 20 will be the next called flap setting, and there will be a marked thrust increase to account for the large extra drag of gear and flaps to about 55% N1. At approximately 1500ft RA, selection of final flap 25 (BA standard landing flap setting, not 30) will result in a small thrust increase from gear down, Flap 20 (due to increased drag - the a/t absorbs the speed decrease of approx. 15kt using the extra drag to reduce thrust lever movement), so that final configuration is achieved and stabilised by 1000ft RA. The SOP trigger for a go-around would be the 500ft RA call - if not in the correct configuration, profile and speed a go-around must be flown.

My point is that by 600ft RA the aircraft should have been correctly configured and with approach power (~55% N1) set. A loss of thrust lever command authority at 600ft RA would only be significant if the thrust setting was towards idle to begin with, and didn't return to the normal 50-55% required with the aircraft in landing configuration.

Either the reporting is incorrect and the fault was identified earlier when the engines spooled up on final flap selection, or the approach was a bit too slick, with the thrust only commanded to come up from <30% N1 to approach power just before the 500ft gate.

The conclusion from the latter case would be that although they mitigated their unfortunate situation extremely well, they could have avoided it altogether by being correctly configured a bit earlier. Engines stuck at 55% N1 are a bit more useful in flight than stuck at 30%!

EGCA

19th Jan 2008, 12:37

Just a quick comment about how totally embarrassed the flight crew looked when they appeared in front of their assembled collegues and the TV and other press. I bet that was the last thing they wanted. They should have been away home to their families.

Maybe the crew of all people were thinking about the "what if" situation, what if whatever happened to the aircraft had happened a minute or two earlier?

Sorry BA, that press call was really not necessary. I feel sorry for the crew now.

EGCA

The Controlller

19th Jan 2008, 12:41

Hands up to all the crew and all involved in immediate action but please please please remember the ops staff who have to keep the operation going and co-ordinate the programme ie diversions/flt crew /cabin crew and looking forward to a normal day (if there is one these days) . Yes we are a team yes are fully aware safety and all that good stuff but the ops staff work all hours to get back on track no matter what happens.
The silent heroes.

BorderLine

19th Jan 2008, 12:41

AlwaysAirbus, remember each of the 3 flight control systems have their own batteries in case of power failure. :)

BuzzBox

19th Jan 2008, 12:47

If I'm not mistaken, the 777 has an automatic icing detection and activation system on it. Been a few years since I flew it at my airline as FO, but it was essentially a no brainer system and whenever the system detected icing, it atuomatically turned the anti ice system on for the engines. No real input needed by the flight crew. Can someone confirm?

Well that's the way the system was originally designed to work in flight, but in reality it didn't always work properly. As a result Boeing came out with a Bulletin some time ago stating that the engine anti-ice should always be selected ON in icing conditions. The contents of that bulletin are now in the Limitations section of the FCOM, ie "the engine anti-ice must be ON during all ground and flight operations when icing conditions exist or are anticipated, except when the temperature is below -40C OAT".

Does TAT probe icing ring any bells for anyone?

AVNBROKER

19th Jan 2008, 12:51

I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK?

The aircraft is totally knackered.....I understand it is going to be declared a constructive total loss with insurers paying out around £65 million to BA. If its found out to be a component/engine/whatever failure then the insurers will be having a rather long chat with those guys and possibly getting reimbursed.

Rick Studder

19th Jan 2008, 12:51

Yes you are right, you cannot stretch the glide by increasing AoA beyound best L/D ratio. Until you are in ground effec that is -- then it makes sense to keep increasing AoA to cash in height for speed. Induced drag is very much lower in ground effect and you can strech the glide quite a bit by such an extended flare. The continued reduction of airspeed until impact is an added positive in a forced landing.

5LY

19th Jan 2008, 13:14

This from the BBC site makes more sense than the pages of drivel I've read here. Go figure!

http://newsvote.bbc.co.uk/nol/shared/img/printer_friendly/news_logo.gif
What went wrong with BA flight?
Air accident investigators have released their first information about the events that led to the crash-landing of BA flight 038 at Heathrow.
The plane landed short of the runway but stayed largely intact, and all 152 passengers and crew on board escaped.
A final report will be released once a much more extensive inquiry has been carried out.

LOSS OF POWER
An initial assessment from the Air Accidents Investigation Branch (AAIB) said that the Boeing 777 failed to respond to demands for extra thrust during its final descent towards Heathrow.
"At approximately 600ft and two miles from touch down, the autothrottle demanded an increase in thrust from the two engines but the engines did not respond," the preliminary report said.
"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 lack of thrust meant the speed of the aircraft reduced, and it came down on the grass short of the runway, the report added.
The findings confirm early theories that the pilots were pitched into a struggle to control the crucial final moments of descent. Only hours after the crash, an airport worker had told the BBC that one of the pilots had described how the aircraft "just shut down".

What remains to be revealed is why both engines failed to respond.
A simultaneous failure of the highly-reliable engines seems unthinkable, so investigators will focus their attention on the plane's systems.
The initial report says that "the range of aircraft systems that could influence engine operation" will now be examined in greater detail. Information from various modules within the plane will be gathered and studied.
The plane's fuel supply, hydraulics, electrical and computer systems are all likely to be examined in this phase.
Theories floated earlier relating to a loss of power also included:
Fuel contamination or starvation - if water got into the system, or some blockage occurred, it would explain loss of power, although not why both engines were hit at the same time
Running out of fuel - although this continues to look unlikely in itself, as the AAIB report says that a "significant amount" of fuel leaked from the aircraft, and in any case that would not explain why no early warning of fuel shortage was apparently given to the crew.
Bird strike - if a flock of geese or other large birds had been hit, the damage could conceivably have been sufficient to knock out or seriously compromise both engines - although the engines are put through rigorous testing to ensure they can withstand this
Wind shear - rapidly-changing winds in very squally conditions can cause planes to stall - but no reports from the area at the time suggest significant wind shear conditions

PILOT ERROR
Key to any investigation is the action of pilots and co-pilots. In some cases, even if they were not responsible for an initial problem, their responses can avert or spark a tragedy.
The picture which has emerged so far from Heathrow suggests that the pilots did a heroic job in getting their stricken plane into the airport grounds and crash-landing without loss of life.
Senior First Officer John Coward was handling the plane at the time, and received warm praise from Captain Peter Burkill for the way the crisis was dealt with.
"We had an outstanding team on board," Capt Burkill said in a brief statement the day after the accident. "I am proud to say every member played their part expertly."
He said everyone had followed procedures as they had been trained to, and that First Officer Coward had done "the most remarkable job".
He added that it was not possible to make any public comment about the circumstances while the investigation was under way.
Air accident investigators will be able to listen to the cockpit conversations between the men, which will have been on one of the plane's two flight recorders. This will help them assess exactly how the crew handled the crisis.
DESIGN FLAW
Until the Heathrow incident, no Boeing 777 had ever crashed, in 10 years of service.
The plane quite simply is seen as one of the most reliable in the world.
Boeing, together with Rolls Royce, which makes the engines, will offer the investigation team any help needed.
From the initial accident report, it appears that the performance of the engines themselves is not in question, but the systems operating them are being closely examined.
The plane involved in the incident is relatively new, at about six years old, and is one of 43 in the BA fleet.
The fact that the plane withstood the crash-landing so well was also key to saving lives.
POOR MAINTENANCE
Some airlines are known to have question marks over their safety records and maintenance standards, but this is highly unlikely to be a factor in an incident involving a major European airline like BA.
An error by an individual technician can never be ruled out, and has sometimes been a key part in a chain of events which brought down a plane, but in this case the fact that the plane had almost completed its long flight from China seems to make it less likely to be a factor.
ATTACK
A major question after any airline crash is whether deliberate attack involving a device on a plane, or sabotage, is a factor. The authorities were quick to make clear there was no indication at Heathrow that any deliberate action was involved.
WEATHER
At the time, weather conditions were favourable and visibility good, although there was a gusty wind which could conceivably have played a role.
Wind shear has been a factor in previous tragedies. If a strong enough gust of wind catches the plane during the critical phase of final descent it can prove catastrophic. But no specific reports suggest conditions at Heathrow were severe enough to trigger this.
GETTING THE FULL PICTURE
The task of investigators from the Air Accidents Investigation Branch (AAIB) will be proving much easier than in many cases, as the flight recorders and wreckage have been easily accessible and not deep under water or damaged by fire.
As well as the recording of cockpit conversations, the inquiry team have accessed the plane's technical data from the second so-called "black box" recorder.
The fact that all crew and passengers survived will also help build up a detailed picture of exactly what happened and over what timescale.
Already it is clear that passengers were given no early warning of a problem with the plane.
Most accidents are caused by a chain of events rather a single catastrophic one, so investigators will be keen to explore all aspects of the incident before reaching their final conclusion.
A fuller report is due to be released within 30 days.

nigegilb

19th Jan 2008, 13:17

I am sure the pilots were thinking about all that theory on final approach whilst staring at the peri road. The only point is they reacted instinctively and calmly to a very nasty situation. That is no accident, it is a result of very good training from BA. Neither hitting the road nor stalling into a field are particularly attractive options, but what they did in the last 2 miles enabled the cabin crew to do their job and get everyone out safely. A truly remarkable feat. In particular, the final hop over the fence, when in all probability the stick shaker must have been permanently on, is the thing that clinches it for me.

Well done to everyone involved. I don't blame WW for the impromptu press conference, there would have been a media hunt on this weekend which would never have allowed these people to get back to their families and their homes. That is the nature of the demands of the modern media.

As for the speculation. Really it is just a competition to try and second guess the investigation. I suspect there is a very simple explanation, which may have far reaching implications; we will know soon enough, of that I am sure.

sandbank

19th Jan 2008, 13:28

John Coward has made some interesting comments to a Sky reporter on the phone.
He said he wasn't aware of anything being wrong until the very final stages of the approach when he suddenly realised there was going to be what he feared would be an almighty crash.

Far from yesterday's statement from the Captain that crew training took over automatically - Coward says there are absolutely no drills for handling a situation such as the one they faced. Whereas there are, of course, procedures for losing power at higher altitudes - there's nothing in the manual to prepare a pilot for what he should do when the power fails at 600 feet

pgomme

19th Jan 2008, 13:32

Hi all,

This is my first post, and I don't want to get flamed, but would just like to throw this into the discussion.

I worked on the CLAWS SHRID component of the 777 PFC at GEC-Marconi Avionics back in 1994, so like to think I have some sort of connection with the aircraft!!

One theory that I haven't yet seen voiced, is the possibly of EMI affecting the engine management system. I think this is highly unlikely, as EMI more often affects navigational and RF receiver devices. Nevertheless, the proximity of the aircraft to landing presents a scenario whereby there is a high likelihood of passengers activating PEDs during the final approach. As the article in September's 1996 IEEE Spectrum reminds, you don't need an intentional RF emitter such as a mobile phone, to cause interference, either in-band or out-of-band.

As I said earlier, I'm not proposing any theory on the cause of the incident, but just wanted to present another scenario for discussion.

787FOCAL

19th Jan 2008, 15:37

You could have a laptop running and a cell phone in every seat and you still would not affect anything on an airplane. :ok:

7times7

19th Jan 2008, 15:37

just a hunch from another angle, though not impossible. don't flame me.

aircraft correcting from low on glidepath to slot on FLCH SPD mode? correction left too late?

Capt handed control to Co-pilot on short finals. Why? Did Capt have to takeover and then hand over? Was co-pilot on training or a check? Did he goofed on FLCH SPD mode with throttle at idle. waiting for it to wake up to hold speed but did not, until a/c stall and too late to spool up manually.

just speculation at another angle.

Ian W

19th Jan 2008, 15:41

PB365: "I wonder if this could point to a software failure? All software has bugs and one worrying statement I have heard is that sometimes a bug will take years to materialize."

Software code tends not to have too many bugs these days, and remember the code in each of the numerous computers on this and other B777s would have been exercised considerably and is being at this moment in the remaining B777s - all apparently satisfactorily. However, the software design - that is the logic and algorithms for dealing with exceptions where inputs from other computers or sensors are timed or scaled in an unexpected way - can have faults that lead to similarly unexpected failures (see http://www.alexisparkinn.com/nwpilot's_tranatlantic_flight.htm (http://www.alexisparkinn.com/nwpilot%27s_tranatlantic_flight.htm) (day 2) http://www.freerepublic.com/focus/f-news/1791574/posts http://catless.ncl.ac.uk/Risks/3.44.html and probably many others). These exceptions are extremely difficult to test for as they may require a series of improbable events to happen in precise temporal sequence. Thus these faults can - as you say PB365 - take years to materialize.

This kind of 'fault' gives a particularly difficult problem to regulators. The chances of the event occurring is say 10 to minus 99 (that is it is less likely than an aircraft being hit by a meteorite on finals) -but in this case it has happened and made headlines so everyone knows it is possible. Do the regulators ground all the aircraft involved at huge impact to worldwide aviation; carry out modifications (that could well introduce similar logic faults); or, do they let the aircraft carry on flying while they carry out modifications or do nothing? Both of the latter options sets up the regulators to be vilified by the tabloid, and sometimes expert. press (not to mention experts on fora like this).

If the cause in this case is something more common then I would think that the AAIB would have already published an emergency alert to all affected operators especially considering the potential impact on transoceanic traffic with ETOPS.

El Grifo

19th Jan 2008, 15:42

Why in that case, is the use of mobiles prohibited in Airliners.

Do you have data to back up your statement.

is that it

19th Jan 2008, 15:44

you don't need an intentional RF emitter such as a mobile phone, to cause interference, either in-band or out-of-band

This is certainly true, but as I'm sure you know given your background, any kind of certified avionics (including FADECs, EECs and the like) is stringently tested for susceptability / immunity over a pretty wide band. This applies to both conducted and radiated EMI.

I would imagine the emissions would have to be at a pretty high level to cause any kind of non-recoverable glitch (latching).

TopBunk

19th Jan 2008, 15:48

Capt handed control to Co-pilot on short finals. Why? Did Capt have to takeover and then hand over? Was co-pilot on training or a check?

In BA it is standard for pilot who does the take off and landing to handover control for the approach to the other pilot (in this case the Captain) until the aircraft is configured for landing and visual with runway. Typically this happens around 1000 ft above airfield.

It therefore would be totally in line with that policy for the SFO to take control from the Captain at about 1000 ft.

All mode selections would have been monitored and verbalised, so FLCH remaining engaged is highly unlikely.

dazdaz

19th Jan 2008, 15:48

Good thinking
Cops routinely use cellular jammers for motorcades.....i.e the PM at LHR maybe? Just a thought.

Daz

pb365

19th Jan 2008, 15:49

787Focal wrote:You could have a laptop running and a cell phone in every seat and you still would not affect anything on an airplane.

I don't know where you get that from, if that was true they wouldn't tell you not to use either. By the way I gather from a pilot mobile phones have been known to cause a plane to do an un-commanded turn in the approach. See:www.askcaptainlim.com

Shaka Zulu

19th Jan 2008, 15:50

@ 7times7

Ba procedures entail a monitored approach ai the p2 flies the STAR and approach for the p1 for the sector.
In this case it would have been the FO's sector and Cpt flying the approach for the FO's landing.
Typically control is handed over at a 1000' (Auto Call out by the RadAlt) by the words 'I have control' (can be done at different stages of the approach but this tends to be the place to do the handover).

No-one flies it at FLCH SPD at that stage on the approach
(2 reasons: if they were unstable they would be flying it manually to correct the path, so AFDS modes completely irrelevant. And: LHR is not a place to come in rushed with all the speed/gate control as appropriate for a CDA)

Enough speculation, just wait for the AAIB report when it comes.
I think you will find there is a very good explanation of what happened.
Why else would the CEO in front of a media frenzy tell the press the crew were heroes...
No company will shoot themselves in the foot.

Agaricus bisporus

19th Jan 2008, 15:54

Far from yesterday's statement from the Capitain that crew training took over automatically - Coward says there are absolutely no drills for handling a situation such as the one they faced. Whereas there are, of course, procedures for losing power at higher altitudes - there's nothing in the manual to prepare a pilot for what he should do when the power fails at 600 feet

Of course training took over automatically, what nonsense!

How could there be drills for total power loss at 600ft - what a ludicrous concept!

The training that took over was to fly the aeroplane so as to survive the landing if at all possible, what the hell else could they do? All they did was to fly the aeroplane, which is precisely what they are trained to do...

The implications of this being a technical failure do not bear thinking about. If this is confirmed we are going to see an awful lot of big twins (read, half of them - the Boeing half alone if we are lucky) lying idle on the ground, as well as hundreds of thousands of pax unable to travel until the matter is sorted. The implications for global aviation in this scenario could make Sept 11th look like a minor temporary glitch...

We rely enormously on ETOPS, any discrediting of the equipment or the concept would change the face of long-range aviation totally.

TwoOneFour

19th Jan 2008, 15:55

You could have a laptop running and a cell phone in every seat and you still would not affect anything on an airplane.

Really? Then how do you explain this (http://www.pprune.org/forums/showpost.php?p=3758275&postcount=3)?

eagle21

19th Jan 2008, 15:57

Forget about approach/flight idle.. The engines are not going to be at idle on a 3 degree glidepath with landing flaps and gear hanging out (The captain said it was a normal approach until 2 miles out). You need thrust to maintain a 3 degree glidepath.

Is this pure ignorance or what? I mean in most major airport we struggle to get the thrust back up by 500ft due to 160Kts to DME 4 so then yes iddle is very normal indeed.

colossus

19th Jan 2008, 15:57

As somebody involved in airport development one thing strikes me, I am not sure what the current ICAO recommendations are on RESA lengths without looking them up, nor how compliant the ones are at Heathow are by the latest standards, but they on this occasion by the narrowest of margins they proved to be enough.

I am sure at certain other airports a failure at the same point in late finals would have been horrendous, it’s certainly an area I will pay a lot more attention to.

It also was incredibly refreshing to see Willie Walsh leading from the front and endorsing the pilots and Crew’s actions without hesitation, I am aware that his background enables him to have better insight to this incident than most senior executives, but made a nice change from the distancing tactics than some employers have shown in previous incidents.

Lets only hope that the investigators at the AAIB are able to identify the causes and make recommendations, thankfully without for once any loss of life or major injuries.

Finrider

19th Jan 2008, 16:03

I believe the advice given to WW2 pilots by the original Pilot Officer Prune was "When a prang seems inevitable, endeavour to strike the softest, cheapest object in the viscinity as slowly and gently as possible...." A job well done by all the crew involved, not forgetting the airfield staff too.

Ian W

19th Jan 2008, 16:03

ILS27L "A lesson: all runways should be like 27Left from now on. This incident could happen again. Same incident on 27 right at EGLL and the 777 would have found the VS Car Park. Slightly harder than the wet grass. RESA needed.
Let's move these car parks."

I second that one. I have seen recent research designs for 'perfect airports' out of universities here in the U.S. (from non-ATC trained engineering professors) where to maintain acceptance rate without runway crossings, the idea of 'end-around' taxiways through overshoot and undershoot areas is recommended and pressed hard. Indeed ATL now has an 'end-around' on 08R but currently only on the undershoot of what is normally a departure runway. The Air France overrun at Toronto and the South West overrun at Midway are other cases that show that undershoot and overrun areas of active runways are not places to be without crossing clearance.

However, the airport operators are driven by the one or two runway operations an hour increase in capacity rather than the potential for collisions. Not to mention all that car parking space!

eagle21

19th Jan 2008, 16:05

You need thrust to maintain a 3 degree glidepath. Not always, not when you just lowered the gear and selected flaps and your plane needs to decelerate about 30 kts.

If I asked you : Can you climb without thrust? You would say off course not! thinking I was mad. But the correct answer is: yes, sacrificing speed.

This just comes to show your lack of experience/knowlegde.

I think is time pprune limits it's access to proffesionals only, this people have no idea what they are talking about.

787FOCAL

19th Jan 2008, 16:08

I have extensive flight test experience. The equipment we bring on board to monitor the aircraft systems, performance and navigation are off the shelf computers and electronics that are hand built.

I can't even count the amount of times I have used a cell phone on the flight deck of an aircraft, many times during approach to tell the wife what time I would be home for dinner. :\

How many of you pilots have used hand held GPS on the flight deck? (I know nobody will answer that)

As one poster pointed out, all the sensative electronics are tested and shielded for EMI.

The reall reason they don't want you using and electrical devices during takeoff and approach is because they don't want them flying into people if a crash happens. How do you think a cell phone would feel at 100 mph?
(I had a can of coke fly from the back of a 727 all the way to almost the front about 3 ft in the air when the pilot hit the brakes when we landed. There was no interior in the plane except a row for me to sit in to watch the wings and make sure nothing flew off during stalls) :ugh:

fyi - Isn't there an airline in the EU that is installing a system that will allow people to make and receive cell calls in flight?

Agaricus bisporus

19th Jan 2008, 16:11

I think is time pprune limits it;s access to proffesionals only, this people have mo idea what they are talking about.

Eagle, would you extend that ban to "proffesional" writers of too?

st7860

19th Jan 2008, 16:16

maybe a sort of check-ride before allowing first post, so to speak.

Waldo.P

19th Jan 2008, 16:17

Forget the computers and bring back the f/e the manual auto throttle!
Good job guys:D

eagle21

19th Jan 2008, 16:25

Agraricus bisporus , (mushroom, for non latin speakers...)
Quote:
I think is time pprune limits it;s access to proffesionals only, this people have mo idea what they are talking about.

Eagle, would you extend that ban to "proffesional" writers too?

Well you may have noticed I corrected the errors on my spelling before you actually posted a time wasting post.
By the way English is not my mother tongue so I do have a excuse...

You wouldn't happen to be the British pilot overflying Egypt 2 weeks ago saying on the radio:
Cairo , XXXX123 , we have tried to call Hurghada on the box , no reply, please give them a call on the landline fo us.

He never realized that it was his english that was causing the problem, what about:

Cairo , XXXX1123, no contact with Hurghada on frequency 123.455 , please call Hurghada by telephone for us.

I don't think that was up to ICAO level 4....:ugh:

L-38

19th Jan 2008, 16:30

In speculating from the peanut gallery, and also with classic B-742 experience, the engines did not spool up when commanded during approach. That statement appears to be fact.

In the B-742, that may point to flight idle not being activated (enabled with flap selection). Does the B-777 have such a system? I suspect that it has.

TheChitterneFlyer

19th Jan 2008, 16:30

What 'reliable witness' said that the engines had spooled up to Take-Off Thrust? And... who says that the RAT can be heard above all of that aerodynamic din? Absolute nonesense!

For heavens sake, this is getting like a circus ring :ugh:

Fenton Freddy

19th Jan 2008, 16:32

Link to B737-800 NASA incident Sep 05 provides excellent evidence of a laptop wireless connection causing false RAs on the TCAS.

We are all aware of the requirement to turn off electronic equipment in the cabin for take-off and landing, but not in the cruise. Do we therefore regard the chance of a false RA in the cruise as acceptable, or was this a one-off incident caused by a fault in the TCAS sensitivity or shielding?

fcom

19th Jan 2008, 16:33

A possible cause to the accident could have been a failure of the autothrust system if this was engaged at the time. If this occured at low altitude at a point of low thrust the engines may have gone to ground idle instead of flight idle therefore needing around 8 secs to wind up again. Factoring in the time to realise the failure and react to it whilst trying to control the A/C all wastes valuable seconds.

Any thoughts from 777 drivers?

It must have been developing some power because if the A/C had a total power failure at 2 miles it wouldn't have much extra speed to trade for height and I doubt whether it would have remained airborne for 40 seconds gliding from only 600 feet.

NigelOnDraft

19th Jan 2008, 16:35

ILS27L "A lesson: all runways should be like 27Left from now on. This incident could happen again. Same incident on 27 right at EGLL and the 777 would have found the VS Car Park. Slightly harder than the wet grass. RESA needed.
Let's move these car parks."Not sure that's needed ;)

Take a look at Google Maps Satellite pics or similar. 27L and R seem to have almost identical grass lead ins, and distances to the 09 LOC aerials. This approach on 27R, IMHO would have been almost identical...

09L/R from piano keys have considerably more distance available, since they are inset Thresholds. From end of concrete less...

NoD

Nigel_the_Normal

19th Jan 2008, 16:47

I can't believe (well I can) the amount of **** on this thread.

1. Why was the FO flying? Standard BA SOP's for his sector.
2. Use of FLCH. No when coupled to the ILS
3. No power until 600'. Not permitted under BA's ops. You have to be in the stable configuration normally by 1000' but ALWAYS at 500'. We have a call at 500 with a reply "stable" or "Go Around".

Stable= Gear and land flap down, approach power set and speed no more that touchdown speed +15kts. I can tell you for a fact they were stable. And I mean fact.

Caudillo

19th Jan 2008, 16:48

For what it's worth, my feeling is that internal and simultaneous (and presumably identical) failures causing this engine failure are almost impossible. I hope.

The initial report leaves some room for conjecture.

So I'm left with two lines of thought.

1. Either both engines had not failed or they were degraded to differing degrees.

2. Given what I suppose above about the chances of an internal and simultaneous failure, I'm led towards thinking the cause was external or environmental.

Again, just a hunch but I believe the stage of flight may prove to be a factor. It may prove to be that the cause of this failure could not have been possible in the cruise.

FWIW I'm going with ice, thermal shock or something temperature related. But I feel that the fact that they were on an approach may be important.

L-38

19th Jan 2008, 16:50

"If this occured at low altitude at a point of low thrust the engines may have gone to ground idle instead of flight idle therefore needing around 8 secs to wind up again."

I also believe that ground idle would contribute to this, however ground idle generally requires ground shift - ie - weight on the gear struts, wheel spinup, ect. . . . It's not unheard of however, for an in-flight aircraft to be in ground mode.

You Gimboid

19th Jan 2008, 16:55

3. No power until 600'. Not permitted under BA's ops. You have to be in the stable configuration normally by 1000' but ALWAYS at 500'. We have a call at 500 with a reply "stable" or "Go Around".

Stable= Gear and land flap down, approach power set and speed no more that touchdown speed +15kts. I can tell you for a fact they were stable. And I mean fact.

If that is the case then the engines must have lost power between 1000ft and 600ft. If the initial report is correct, the engines did not respond to A/T or pilot commanded changes at 600ft. If the thrust was already set at stable approach conditions, then the failure to respond to commands would have meant they remained at the selected thrust setting, no?

To land 300m short means they must have had significantly less thrust than that required to make a "normal" landing, so the power setting must have changed (degraded) in the interim.

Contacttower

19th Jan 2008, 17:00

Stable= Gear and land flap down, approach power set and speed no more that touchdown speed +15kts. I can tell you for a fact they were stable. And I mean fact.

So if they were stable, with approach power set one can assume that the autothrottle wasn't asking for that much power when the engines failed to respond, surely they must have had considerably less than 'approach power' on for this to happen...unless of course the engines actually lost power (which the AAIB didn't mention). What sort of N1 would a 777 have on for an approach like that?

Sorry You Gimboid you beat me to it!

Sallyann1234

19th Jan 2008, 17:01

How many of you pilots have used hand held GPS on the flight deck? (I know nobody will answer that)

GPS is a receiver only - it doesn't transmit.

As one poster pointed out, all the sensative electronics are tested and shielded for EMI.

EMC is not absolute.
Filtering components are no more reliable than any other electronics. They can and do fail.
Shielding can be damaged, left off or left unconnected after maintenance.

Nigel_the_Normal

19th Jan 2008, 17:02

The aircraft was stable but aproach power does not have to be absolutely set until 500'. It may be that spped was reducing to vref +5 (or whatever they were using) at 600'. However it is clear that at this point or at 500' things would have been normal. From there on the aircraft would have continued to lose speed. The A/T would then have demanded more power which it would appear never arrived for one reason or another.

Both auto and of course manual thrust is available. Neither gave the power required to maintain the speed. Then you have to sacrifice something, speed or height.

Their actions ensured that no-one was killed.

Lost in Saigon

19th Jan 2008, 17:03

So if they were stable, with approach power set one can assume that the autothrottle wasn't asking for that much power when the engines failed to respond, surely they must have had considerably less than 'approach power' on for this to happen...unless of course the engines actually lost power (which the AAIB didn't mention). What sort of N1 would a 777 have on for an approach like that?

Did you consider that maybe the wind conditions on final are not always constant?

andersoj

19th Jan 2008, 17:06

Why there aren't cameras trained on active runways by default? It would seem a simple measure, and if the local Kwik-Mart can afford it and thinks it worthwhile, it would seem that aviation safety would gain from it...

JA

You Gimboid

19th Jan 2008, 17:06

Do you mean Flap 20 Nige? they should have had Flap 25 set already (SOP for LHR)

That would mean they still had full hydraulic power available. Curiouser and curiouser!

Tercarley

19th Jan 2008, 17:08

Was involved in a major incident a few years ago and Flight Crew and family were all absolutely forbidden to speak to the press never mind about contacting a publicist!!

PJ2

19th Jan 2008, 17:09

One of my sources also tells me that the Captain quite instictively selected flap to 25 to reduce the drag. If this is the case I would suggest that this stopped them hitting the road or ILS bank, and almost certain death.
Although one does what one must in an emergency, I doubt the statement's veracity. It just doesn't make sense given the loss of lift and the increase in rate-of-descent at that stage of the approach, (last 400' or so) where recovery from loss of lift would not be possible - but...the data's not available to us so...

Hand Solo

19th Jan 2008, 17:09

They can't forbid your family. They don't work for BA.

Contacttower

19th Jan 2008, 17:09

Have you ever flown a real airplane?

Errr...yes. Of course wind is a factor (in fact I suggested earlier a combination of erratic autothrottle settings and changing wind speed could have combined). But it's good technique to keep the power reasonably constant on final (in fact especially in windy conditions) and while the autothrottle may have momentarily retarded the throttles back I find it difficult to believe that it took so much power off that they landed so short.

Greensky

19th Jan 2008, 17:13

Someone mentioned Flap 25 as standard landing flaps for BA. How lucky in this case...imagine the greater drag from a Flap 30 landing combined with the lower Vref +5 speed that they would have been at...wonder if they would have then cleared the fence if they had indeed lost thrust on both engines...scary thought.:eek:

Nigel_the_Normal

19th Jan 2008, 17:15

Lost

BA pilots are more than aware that conditions on final can vary. That is why we set an appropriate spped (ref +5,10 or 15). Approach power is set for these conditions initially but then has to react (or you do) appropriately.

The 1000 and 500' stable checks are to ensure you are not in a rushed approach situation.

If you are at 1000' you consider a G/A, if you are not stable at 500 you must G/A.

FrequentSLF

19th Jan 2008, 17:19

Filtering components are no more reliable than any other electronics. They can and do fail.
Shielding can be damaged, left off or left unconnected after maintenance.

Boeing is installing wifi transmitter/receivers on the new 787, this means tthat Boeing is not overly concerned about trasmitting devices.
http://www.pprune.org/forums/showthread.php?t=307849

787FOCAL

19th Jan 2008, 17:20

Well all I can say is out of hundreds of flights I have never seen any of it cause any problems on 100s of different aircraft.

Isn't engine out flap 20 on the 777?

Seggy

19th Jan 2008, 17:20

It is going to be interesting to see the FINAL accident investigation report. There is going to be a lot of 'politicing' going on behind the scenes with this one.

Great job to the flight and cabin crew.

Albert Driver

19th Jan 2008, 17:26

I say again.......the right engine fan blades are plainly visible and still intact. This means the engine was not delivering power when the aircraft and both nacelles hit the ground. Even at idle power one would expect to see the blades stripped by the sudden deformation of the nacelle, such as is plainly evident in the left engine. This suggests the engine may have run down between 600 feet and impact.

Nigel_the_Normal

19th Jan 2008, 17:29

In normal ops (CAT 1) the handover of control is at 1000' or lower, but nothing stops you taking it before if visual.

You can then leave the A/P and A/T in until aircraft limits which vary by type.

The A/T can be left in until the flare on most types but some BA fleets leave it in throughout I believe and an SOP. I don't fly the 777 so I'm not sure what their SOP is.

Flap 20 may well be the eng out flap. They didn't have an engine out for single engine ops. I'm told the flaps were set for a flap 30 landing but were moved last minute to 25 as the position of impact clearly would not be 27L

TRPL7

19th Jan 2008, 17:30

that's correct! The 777 APU autostarts incase of a dual engine failure.

AirwayBlocker

19th Jan 2008, 17:33

787FOCAL

Well all I can say is out of hundreds of flights I have never seen any of it cause any problems on 100s of different aircraft.

Just because you haven't seen it, doesn't mean it doesn't exist. A link has already been provided to an example where TCAS error's were experienced.

Although I haven't experienced anything myself I do have colleagues who have.

The biggest problem is isolating the exact cause. Often the person using the personal electronic device is never found. Their seating position and type of device used in combination can sometime cause a problem where other times nothing would occur. Even the frequencies that the aircrafts radios and nav-aids are tuned to can influence whether the PED has an effect on the flight.

M.Mouse

19th Jan 2008, 17:34

One of my sources also tells me that the Captain quite instictively selected flap to 25 to reduce the drag.

Sound like yet more daft supposition to me. If I have to explain why then you plainly now little about SOPs on BA 777s nor, it would seem, basic aerodynamic theory.

I read this thread for entertainment value. I have never read so much utter rubbish on one thread on Prune, ever.

In normal ops (CAT 1) the handover of control is at 1000' or lower, but nothing stops you taking it before if visual.

If you must quote BA SOPs then please be accurate, some of that statement is not.

snowfalcon2

19th Jan 2008, 17:39

Although one does what one must in an emergency, I doubt the statement's veracity. It just doesn't make sense given the loss of lift and the increase in rate-of-descent at that stage of the approach, (last 400' or so) where recovery from loss of lift would not be possible - but...the data's not available to us so...

This one I'd really like to see some details on. In theory, what you want in that situation is maximum glide rate regardless of the rate-of-descent, because that will bring you the farthest distance. But cleaning up the airplane to flaps 0 was clearly not an option in this case, when the plane had already slowed down to stick-shake speed. To me, one notch less flaps sounds like a not-too-bad compromise in the circumstances. It would be great if someone did the math as to what the optimum course of action would be in this kind of situation. :) Anyway, what the crew did in this respect turned out to be good enough, so kudos for that. :ok:

Contacttower

19th Jan 2008, 17:39

So if they were stable...and everything was normal until 600ft where on earth does the eye witness report that the plane was banking at 45 degrees come from? Assuming that they were lined up with the runway banking would be the last thing to do.

ribt4t

19th Jan 2008, 17:43

Boeing is installing wifi transmitter/receivers on the new 787, this means tthat Boeing is not overly concerned about trasmitting devices.
http://www.pprune.org/forums/showthread.php?t=307849

Aircraft manufacturers have long insisted that there is no risk to aircraft electronics from passenger carried devices. There are other reasons not to use them in the air however. The leading one for mobile phones being that the network behavior is unknown where large numbers of users are in range of large numbers of cells while traveling at hundreds of miles per hour. Something that was likely never designed into the network.

As another poster said use during takeoff/landing presents the risk of injury from flying devices. Not to mention at critical times it is extremely important that people aren't distracted from hearing important crew instructions.

787FOCAL

19th Jan 2008, 17:43

Just because you haven't seen it, doesn't mean it doesn't exist. A link has already been provided to an example where TCAS error's were experienced.

Although I haven't experienced anything myself I do have colleagues who have.

The biggest problem is isolating the exact cause. Often the person using the personal electronic device is never found. Their seating position and type of device used in combination can sometime cause a problem where other times nothing would occur. Even the frequencies that the aircrafts radios and nav-aids are tuned to can influence whether the PED has an effect on the flight.

Well I suppose anything is possible.

RatherBeFlying

19th Jan 2008, 17:44

Pending definitive information, I would assume that that the 777 was stabilised on glideslope and on speed by 600' when it went through a windshear transition that presented it with an airspeed decay. The a/t would then be asking for more thrust which was not obtained.

Without added thrust, the only reasonable way to regain airspeed is to lower the nose and that's going to cost you a significant altitude loss.

But if you look out the window and see that regaining all that airspeed will leave you short of the fence with the power available, you then get to work out a pitch attitude that will hopefully get you over the fence. As long as the resultant speed is over the stall, you have something to work with.

What you will not have at touchdown at an airspeed close to the stall is enough energy to flare; so, the gear may be overloaded and come up through the wings.

2 nm out is about 12000' and it looks like they landed 2000' short of the glideslope; so that gives them a glide of some 10000' from the 600' point.

The 3 degree ILS glideslope is ~ 20:1.

Remember that before the windshear, the 777 was achieving 20:1 against the ground and that once restabilised, it would achieve a bit better than 20:1 at the same airspeed and power because of the decreased headwind. The problem would be the inability to regain the ILS.

If we apply the 20:1 slope for 10000', we obtain 500'; so it looks like the lack of additional thrust to counter the windshear engendered an altitude loss of ~ 100'. Given the high AOA shown crossing the roadway, I suspect they lost more than that and resorted to a lower airspeed to shallow out their glide.

bealine

19th Jan 2008, 17:45

Well said M.Mouse!

I'm sick and tired of all the speculation - perhaps people feel an irresistible urge to see their pet theories in the press as, no doubt, a reporter or two will pen some tripe gleaned from the pages of Pprune as a "verifiable source of pilot materiel!"

The AAIB will get to the bottom of this incident and when they make their report public, we shall find out exactly what has happened.

Until then, I thank God that all of our passengers and crew are safe and I take pride in the actions of my Flying colleagues - those at the sharp end who managed to avoid certain disaster, the cabin crew who acted swiftly to evacuate and my own ground staff colleagues who did a sterling job (although some of the idiots of the press might not think so!) :ok::ok::ok:

........oh, and some tw4t on Flyertalk suggested lack of maintenance might be to blame! Bo77ocks! Despite all the cost-saving initiatives, there have never been any cuts in BA that would compromise safety!

Our Engineers are first-rate and I'm bloody proud of them too!:ok::ok::ok:

ChristiaanJ

19th Jan 2008, 17:47

One theory that I haven't yet seen voiced, is the possibly of EMI affecting the engine management system.It has already been suggested, but with 700+ posts you may have missed it.
....a scenario whereby there is a high likelihood of passengers activating PEDs during the final approach. As the article in September's 1996 IEEE Spectrum reminds, you don't need an intentional RF emitter such as a mobile phone, to cause interference, either in-band or out-of-band."...passengers activating PEDs during the final approach.." does happen all the time. Both engines not spooling up when commanded to do so, doen't. I'm not dismissing it out of hand, mind you, but I don't think it's at the top of the list.

SLFJan

19th Jan 2008, 17:48

BBC website is reporting that they will try to move the plane tomorrow morning

http://news.bbc.co.uk/1/hi/england/london/7197506.stm

Contacttower

19th Jan 2008, 17:48

Does the fact that this accident involve British Airways (arguably the world's safest airline) have everyone automatically thinking that the crew were infalliable?

Simply a cocked up approach was the first thing a thought of when I saw the news for the first time...and at first I was suprised that no one mentioned pilot error (well I did actually but that was early on). It just seems unlikely that BA would let them read a statement out and that the captain would sound so confident in praising his crew if there was any suggestion that they might have done something wrong.

sandbank

19th Jan 2008, 17:50

John Coward has spoken on the phone to a Sky News reporter who was in his mother's house today. Therefore there seems no BA instruction on the crew not to talk.

captwilga

19th Jan 2008, 17:51

I spent 30 years flying jets for BA and only once had an engine problem, threw a blade on a Trident just after T/O at LHR.Modern jet engines just don't stop until the fuel supply is cut off and autothrottle/ engine management systems don't either. When was the last time your car engine quit!
Long flight, permanent jet lag, over familiarity, who knows, certainly not me. It is interesting that Willy paraded his pilots to the media and a little strange that the SFO didn't say a word. Didn't look too happy either.
Lets wait for the report-the CAA have everything they could possibly wish for so it shouldn't take them too long to find out what happened. They probably already know.

egbt

19th Jan 2008, 17:51

Nigel_the_Normal

19th Jan 2008, 17:52

My sources tell me that John was duped into making a statement as they had gained access to his Mothers house.

There is a standing instruction not to speak to the press.

blueoreas

19th Jan 2008, 17:53

I just found this interesting.

http://www.imp-detail.org/archive.php?apid=112

Aircraft: B767 Undifferentiated or Other Model
INSTRUMENT MALFUNCTION AUTOPLT ABNORMALITY. CLR OF CLOUDS, FL350, ECON CRUISE 'MACH .78,' SMOOTH AIR. THE FO WAS FLYING THIS LEG WHEN 30 NM NE OF LEFKO INTXN ON GREEN 26 PROCEEDING DIRECT TO REDFIN, JAX CENTER CLRED US DIRECT REMIS FOR A WARNING AREA HAD GONE ACTIVE. AT APPROX XA:44 ENE OF REMISS WE ENCOUNTERED THE EVENT. FIRST THING I NOTICED WAS THE AMBER AUTOPLT AND AUTO THROTTLE EICAS MSG AND AUDIBLE ALERT FOR A DISCONNECT. WE ALSO NOTICED SOLID YELLOW LINES THAT WENT THROUGH ALL FLT MGMNT CTL DATA ON BOTH CAPT AND FO ADI'S AND HSI'S. I LOOKED AT THE TOP EICAS ENG INSTRUMENT AND NOTED NO N1 OR EGT DIGITAL READOUTS, ONLY WHITE CIRCLES REMAINED. LOWER EICAS REFLECTED THE SAME. NO DIGITAL INFO FOR F2, FF, OIL PRESSURE, OIL TEMP, OIL QUANTITY, VIB. BOTH CDU'S WERE BLANK. AN IMMEDIATE CHK OF THE ELECTRICAL PANEL INDICATED NO MALFUNCTIONS, A TEST OF INDICATOR LIGHTS REVEALED NO BURNED OUT LIGHTS. CENTER AUTOPLT WAS ENGAGED AND SHOWING PANEL ACTIVE WITH NORMAL INDICATIONS. STANDBY ADI INDICATED WE WERE STARTING A LEFT BANK. WITH WARNING OF AUTOPLT AND AUTO THROTTLE DISCONNECT I GRABBED THE YOKE AND HIT THE AUTOPLT DISCONNECT SWITCH AND DIRECTED THE FO TO FLY. HE MAINTAINED LEVEL FLT AND STATED THAT THE AUTOPLT WAS STILL ENGAGED. I ATTEMPTED TO DISENGAGE THE AUTOPLT WITH THE DISENGAGE BAR BY PULLING IT DOWN AND WAITING. THE WHITE AUTOPLT CMD LIGHT REMAINED ON. I WENT BACK TO THE YOKE AND AGAIN HIT THE DISCONNECT AND FELT THE YOKE PRESSURE THE FO WAS HOLDING. [Brief synopsis: while flying, an alarm sounded indicating that the autopilot had disengaged itself. The following displays that indicate the status of the aircraft stopped functioning: ADI (Attitude Direction Indicator), HDI (Horizontal Situation Indicator), EICAS (Engine Indication and Crew Alerting System - the acronyms the pilot references on this system are N1 (compressor rotational speed), EGT (exhaust gas temperature), and FF (fuel flow)), CDU (cockpit display unit, a radar display). The pilot performed several system checks which all claimed that equipment was functioning normally. When the plane started making an uncommanded left turn, the pilot attempted to manually disengage the autopilot (which was still operating despite the warning saying it had stopped) but was unable to.] I CALLED ATC AND ADVISED WE WERE HAVING SOME KIND OF AN ELECTRICAL ANOMALY. JUST AFTER THE CALL TO ATC THE AUTOPLT DISENGAGED AND THE WHITE CMD LIGHT WENT OUT AND ALL SYSTEMS RETURNED TO NORMAL OPS. I DIRECTED THE FA 1 TO SEARCH THE ACFT FOR UNAUTHORIZED ELECTRONIC EQUIP BEING USED. I THEN RPTED TO ATC THAT OPS WERE NORMAL. THE EVENT LASTED APPROX 45 SECS. [...] FA 1 RPTED A CELL PHONE WAS IN USE BY PAX. I DIRECTED FA 1 TO HAVE IT TURNED OFF AND CONFISCATED TO ME. PAX STATED IT WAS A NEW PHONE BY AT&T, MODEL SIEMENS CEO168, HE WAS INSTALLING NEW PHONE NUMBERS IN DATA BANK AND NOT TALKING ON PHONE. MAINT WAS CALLED AND STATED THE ACFT HAD NO PREVIOUS HISTORY OF THIS TYPE OF EVENT. ONE AREA OF CONCERN WAS A POTABLE WATER TANK GAUGE QUANTITY PROB. THE FO AND I COMPLETED A COMPLETE SYSTEMS CHK CONCLUDING OPS NORMAL. WITH PASSENGER'S CELL PHONE OFF AND IN MY POSSESSION THE FO AND I AGREED WITH DISPATCHER TO CONTINUE THE FLT WITH CAVEAT THAT SHOULD ANY OTHER SIMILAR EVENT OCCUR WE WOULD LAND ASAP. [...] FROM NAVIGATION POINT REMISS WE PROCEEDED UNEVENTFULLY TO SFO. [...] THE CELL PHONE THAT WAS ON AT THE SAME TIME IS RPTED TO BE A POWERFUL NEW TYPE IN THE SEARCH MODE. THE LOCATION OF THE PHONE DURING THE INCIDENT WAS THE CABIN AT SEAT ROW X WHICH IS ROUGHLY ABOVE THE ELECTRONICS AREA. DURING THE FAILURE THE STANDBY ENG INSTRUMENTS ACTIVATED.

Hand Solo

19th Jan 2008, 17:55

Modern jet engines just don't stop until the fuel supply is cut off and autothrottle/ engine management systems don't either. When was the last time your car engine quit!

Not really a great example. My brother's modern engine managed German car has conked out three times with the same fault. When my different engine managed car went mental the mechanic knew what it was immediately. Just because the MBTF is much higher on an aircraft than a car it doesn't mean the failure won't happen eventually. Unless you can verify that absolutely nothing happened to affect the link between the flight deck and the FADECs I'd steer clear of allusions to fuel starvation.

Feathers McGraw

19th Jan 2008, 17:55

FrequentSLF (and others talking about this aspect)

It's one thing to install Wi-Fi transceivers in an aircraft, and quite another when a consumer-grade product such as a laptop Wi-Fi transceiver is used aboard.

The former kit will be individually tested and be very carefully designed to have very low spurious (i.e. out-of-Wi-Fi-band) emissions.

A laptop might have poor spurious emissions because of a fault in assembly or manufacture, but as this is not tested for 100% of the production runs (it relies on type-approval of a small sample of units) there is ample opportunity for a problem like this to be limited to a single laptop and perhaps to the combination of that faulty laptop and an aircraft with a small defect in screening or grounding of the avionics, perhaps due to wear and tear or a maintenance error.

Note that Wi-Fi is usually not designed with power control of its transmitters (it's short range, so fixed output power is OK) whereas cellular phones are designed to have power steps to maximise the capacity of each cell and to reduce the variation in signal levels at a base station (essential for CDMA systems such as 3G).

The latter suggests that allowing indiscriminate use of Wi-Fi devices is riskier than allowing the use of mobile phones in the air.

AmericanFlyer

19th Jan 2008, 18:00

There have been many remarks made about how independent the two engine control systems are:

Separate power supplies
Separate computers
Separate almost everythingHowever, I believe it is highly likely that both computers were running the same software. If the software were fed the same inputs, and there was an error in the software, they could both output the same erroneous controls to the engines. I'm not saying that this is what caused the crash. What I'm saying is that just because everything appears to be physically separate does not mean that they could not fail simultaneously from the same fault, if that fault is a software fault.

I have worked professionally in the software development business for thirty-eight years, and I have personally seen this very type of software fault cause the failure of many online banking systems. It is very difficult and expensive, but worthwhile, to avoid. Many persons do not realize how dependent their very lives have become on computer software and silicon today.

On the space shuttle, there are three main computers which handle operations and decision-making processes. NASA had them independently programmed in three different languages by three independent teams of software developers, but to the same specifications in terms on inputs and outputs to avoid this very issue. In case of disagreement, two of the three computers could vote to over-rule the third computer output.