AAIB initial report out on BA B777 crash at LHR

[Tediek]

interesting all these speculations, however, maybe the engines were running but not at the required power settings, you will go down too.

[alistairbailes]

interesting all these speculations, however, maybe the engines were running but not at the required power settings, you will go down too.


Sure. Only one engine was running! See post 267.

[Wader2]

They would be rotating even if not producing power.

I didn't say it was producing power, simply that it was rotating.

The previous post seemed to suggest that no evidence of damage was evidence of not running.

It both engines were rotating then is it not possible that both engines were similarly vulnerable to blade damage - powered or not - but that blade damage would depend on the nature of the damage instrument.

One engine has evidence of soil spread around its fan; the other has a heap of soil piled in the lower fan segment.

I am simply making observations from the photographs not drawing any conclusions that it for you experts.

[OVERTALK]

FAA AD AD 99-27-15 of 11 Jan 2000 (link (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/b51bf59705afd3e4862568820061cbea)) a situation applicable to GE engines on the 777 addressed a known fault


"....applicable to certain General Electric Company GE90 series turbofan engines. This action requires visually inspecting Ps3 and P3B sense lines and full authority digital engine control (FADEC) Ps3 and P3B sensing ports and fittings, cleaning Ps3 and P3B fittings and sensing ports, purging the Ps3 and P3B systems of moisture, and, if necessary, blending of high metal, nicks, burrs, or scratches on Ps3 and P3B fitting threads. This amendment is prompted by seven reports of loss of thrust control due to corruption of the signals to the FADEC caused by water freezing in the Ps3 sensing system. The actions specified in this AD are intended to prevent loss of thrust control due to corruption of the Ps3 and P3B signals to the FADEC which if it occurs in a critical phase of flight, could result in loss of aircraft control."

.

It's not beyond credibility to see that the same situation could apply to the air and fuel pressure reference lines in the FADEC(s) attached to an RR Trent engine - as pointed out at:
.
http://tinyurl.com/2nx3ym
.

[meekmok]

Has anyone commented on this? I haven't noticed it. In today's Daily Telegraph there is a letter suggesting exactly this and that all cell phone logs and laptops should be recalled and checked to see if they were operating.

And that will prove exactly .... nothing. If you were to take a look at all the phone and laptop logs of all the passengers going into Heathrow for a given day/week/month, you'd probably find anywhere from 0.1%-10% were in use at landing? And funny enough a plane doesn't crash every day/week/month at Heathrow....

[VnV2178B]

The problem with P30 icing on R-R engines has been known and compensated for at least since the RB211 FAFC equipped units. I can see no reason why Trents are not similarly fitted.

Even if P30 is lost the FADEC will fail to reversionary mode using speed and temperature rather then EPR as the main control parameters.

I am not allowed to speculate further.

VnV

[Contacttower]

c.40 seconds is the figure that is appearing most...

or more precisely if they were doing 140kts at 2 miles it would have been 51 seconds to the runway.

[awair]

As a current 777 pilot, I am obviously concerned about any UNEXPLAINED accident, and believe that for the most part this and the previous thread has produced a useful discussion.

Its been difficult to assimilate all the unanswered, misleading and incorrect quotes before my reply so apologies if this duplicates earlier posts.

FACTS
AAIB reports that the engines 'did not respond' - this does not imply they were still running OR that they had failed, that will be answered in a later report. [The AAIB report into Kegworth gave detailed engine parameters at all relevant stages of flight.]

The RAT is visible in the post 'landing' photos. From these I am not able to determine whether it had been deployed or not. Discussions with a 777 engineer result in speculation that it was deployed [it would have been contained in the fuselage otherwise. The right wing/engine geometry may have prevented a deployed RAT from being torn away during impact].

The APU door is open, this does not imply that the APU was running at any stage that may have been relevant.

The Captain is reported to have stated that all power and avionics were lost.

No passengers reported any loss of lighting/facilities prior to landing [- is this a fact or a lack of one?]

Passengers reported increased engine noise.

PROCEDURE
Recall actions for Dual Eng Fail/Stall are applicable when "engine speed for both engines is below idle"
These actions include manually deploying the RAT and starting the APU.

In flight, the RAT will deploy automatically if:
-both engines are failed and center hydraulic pressure is low
-both AC transfer buses are unpowered or
-all three hydraulic system pressures are low.

In flight the APU will start automatically when both transfer buses are unpowered.

At 190 tons Vref30 is approximately 132 & Vref25 is 138. [With nil wind 2nm will be covered in approximately 50 sec at these speeds].

CAUSE - OPTIONS
1.Flown into ground (mishandled)
2.Thrown into ground (eg windshear)
3.'Knocked' to ground (eg birds)
4.Fell to ground (loss of thrust etc)

CONCLUSIONS
IF the rate of descent was allowed to double [due to loss of thrust] the crew would have about 25 seconds until contact.

'Dual Engine Failure' (as defined above) will result in loss of thrust and most flightdeck displays until electrical power is restored. This fits the description attributed to the Captain. Apparent position of RAT/APU door lends support to this theory.

IF recall actions had been completed promptly, it is possible that one or both engines may have restarted prior to impact.

PURE SPECULATION
I believe that only option 4 above is feasible, obviously 'WHY?' is going to take a while. The crew had an indication of a dual loss of thrust, probably dual engine fail, resulting in numerous EICAS alerts, loss of flight displays AND very little time to effect a recovery.

They were very lucky to walk away [not disputing the skill involved].

CONCERN
My last 4 approaches [from 1500' - 300'] we would not have had a chance at making any clear area.

Until a prime cause of the loss of thrust is determined there is a probability of a re-occurrence. Still no AD issued on this?

QUESTIONS
Was flap setting changed prior to touchdown - any simulations to indicate effectiveness at prolonging the glide?

Confirm BA SOP is F25 @ LHR?

Confirm BA/777 fleet stabilisation criteria, and usual method of handling '160 til 4' [On the -300 with Vref 149, we start reducing at about 6 miles and are normally within a couple of knots of the assignment.]

[Please fell free to PM me if you are concerned about confidentiality.]

[Tediek]

awair (http://www.pprune.org/forums/member.php?u=103213) , i can only say, great feedback that makes sense. The outcome will shine light on the accident but it great outline of possibilities and options.:ok:

[Machaca]

Stitched together from vid-caps of footage taken from helicopter that was moving forward and then up. I adjusted perspective of each as best I could:

http://img527.imageshack.us/img527/9215/ba38impacttrailtv2.th.jpg (http://img527.imageshack.us/my.php?image=ba38impacttrailtv2.jpg)


-=MachacA=-

[gordonroxburgh]

Great overhead image.

Some deductions from this:

Landed on all 3 gear legs and bounced

Port gear went straight up though the wing pretty much on first contact, the starboard gear failed.

On 2nd "landing" the main contact was with engines and nose gear.

The aircraft stayed on the ground this time, the engines plouging through the grass, tearing off the failed starboard gear.


Looking at this picture, it was fortunately that they did not hit the concrete with their vertical velocity, the structural damage and passenger injuries could have been far worse. The soft grass obviously absorbed a lot of kinetic engery.

[SaturnV]

Awair, the initial AAIB report was based on a preliminary readout of the FDR (and crew interviews). The AAIB report states the analysis covered the final phase of the flight. As the FDR covers approximately 700 parameters, if there had been an engine shutdown and/or loss of avionics, one can rightly presume note would be made of such in the initial AAIB report. The only anomaly cited was the non response of the engines to commands for increased thrust.

There is both video and still photography of the plane just before it reached the grass at Heathrow. The RAT is not out.

With respect to this particular incident, the AAIB is fortunate to have data from the FDR and the QAR, covering several thousand parameters. That is an extremely rich data set. It also has a largely intact aircraft, with an undamaged cockpit and quite probably undamaged avionics. If the data points to a potential hardware failure, the suspect equipment can be examined and tested.

In my opinion, the more days that pass without the issuance of an AD or SB related to this accident, the less likely that the cause will be a hardware failure or a software error, at least a failure or error that might be replicated or present in the systems of other 777's.

[OVERTALK]

In response to the post by OVERTALK at #268 (http://www.pprune.org/forums/showpost.php?p=3855375&postcount=268) of this thread,

VNV2178B said:
The problem with P30 icing on R-R engines has been known and compensated for at least since the RB211 FAFC equipped units. I can see no reason why Trents are not similarly fitted.

Even if P30 is lost the FADEC will fail to reversionary mode using speed and temperature rather then EPR as the main control parameters.

I am not allowed to speculate further.

However to quote further (below) from the AD itself, it would appear that the FAA had genuine concerns about the possibility of LOTC (Loss of Thrust Control) on the Triple 7 - which is exactly what happened to Flight BA038 after an extended period of cruise in very cold temperatures at height - during a 12 hour trans-polar operation. In addition, any prolonged CDA descent at near idle power has the potential to:
a. Allow greater than normal cooling within the nacelles

b. Disguise the fact that the engines are "locked at/near idle" due to the FADEC's reference pressure sensing lines becoming obstructed by waxy ice crystals.

I'm not aware whether or not the FADECS are just similar (or the same) on GE, Trents and P&W, however the possibility remains that the problem is replicable across the GE's and Trents. I doubt that it is just a mere coincidence.

QUOTE FROM the Airworthiness Directive: (link at http://tinyurl.com/2nx3ym)

Simultaneous LOTC Events

The FAA is especially concerned about the possibility of simultaneous LOTC events on both engines installed on the Boeing 777 series aircraft due to common mode threats, such as certain atmospheric conditions that may result in ice in the Ps3 or P3B pressure sensing system and causing corrupted signals to the FADEC in both engines.

SUMMARY: This amendment adopts a new airworthiness directive (AD) that is applicable to certain General Electric Company GE90 series turbofan engines. This action requires visually inspecting Ps3 and P3B sense lines and full authority digital engine control (FADEC) Ps3 and P3B sensing ports and fittings, cleaning Ps3 and P3B fittings and sensing ports, purging the Ps3 and P3B systems of moisture, and, if necessary, blending of high metal, nicks, burrs, or scratches on Ps3 and P3B fitting threads. This amendment is prompted by seven reports of loss of thrust control due to corruption of the signals to the FADEC caused by water freezing in the Ps3 sensing system. The actions specified in this AD are intended to prevent loss of thrust control due to corruption of the Ps3 and P3B signals to the FADEC which if it occurs in a critical phase of flight, could result in loss of aircraft control.

Interim Action

Both Ps3 and P3B pressure systems incorporate weep holes that allows drainage of water in the lines that may accumulate from condensation or ingested water; however, the field events and the investigation have determined that these design features may not always be effective in eliminating water from these systems. GE is assessing design changes that will prevent water from freezing in these systems and causing corruption of the signals to the FADEC. The requirements of this AD may change based on the ongoing investigation of the root cause and field inspection results, and future rule-making may be necessary.

[ACMS]

OVERTALK: I understand that BA38 held at LAM? If so they WOULD have spooled up power more than once and your theory above might not hold water.

[Ian W]

:
Therefore I do not see that CDA per-se would have any bearing on this although it is possible that the BA or NATS procedures for flying them at LHR might have some impact.That wasn't the point I was making. It was that a continuous descent at idle (if that is what occurred in this case) might have masked the problem whereas a step down to a platform altitude would have required a power-up and so revealed the problem at an earlier point in the approach. The crew would then have had the option of delaying gear/flap which might have enabled the aircraft to reach the runway. I fully agree with your point.
If you read my original post I said that CDAs were poorly defined, and that the flavour of CDAs used by LHR were a long final approach intercepting the glide path several thousand feet earlier than normal. I also stated that NATS and BA had agreed procedures that were particular to the approach at LHR.

In this case the procedure was the 160 to 4 as it appears to be known. This does not seem to have been assessed for the risk of a double engine failure to spool up after the slow down from 4 to ~2 miles. In fairness this has not happened before on this approach. However, in safety research a risk greater than '10 to the minus 9' is (supposedly) unacceptable - and that would mean (roughly) something that happens once a second cannot go wrong more than once in 32 years. The acceptance rate of LHR is only around once every 40 seconds at best and the procedure has only been in place around 2 - 3 years (?). So although it is a rare event it may still unacceptable in 'pure' safety terms - but then practice and theory are often different. (Before the anal mathematicians start probability theory on me - I know that probability does not mean it can't happen immediately but that is not the point - it was not considered)

So after all that - NATS and BA may well change the procedures a little - I read in an earlier post that some operators prefer to be stabilized on the approach a lot earlier - I think that this is justified. There comes a time when you have to balance noise nuisance with safety.

However, I do not think that CDAs will go away as the potential financial savings are huge. Research I did for Atlanta showed that savings of 45 flying hours per day were possible. Added to the research from SAS with savings of up to 1000Kg of fuel per approach and the argument for a full CDA is difficult to refute. But late spooling up of engines may be seen as too much risk - and this may result in stabilized approaches from say 5 miles.

This is where safety meets environmental impact (read political problems) - and who knows which way the decision will go?

[mocoman]

NATS and BA may well change the procedures a little

c.f
suggestions made recently regarding the modification of the EGLL ILS to instruct inbounds to land further down the runway for noise/environmental reasons.

These proposals would have made the incident far more serious; landing on hard standing rather than soft turf would have exacerbated the problems already present within the aircrafts' final approach profile as well as exposing the passenger terminal, and aircraft taxiing, areas to more direct exposure to the incident.

Additions:
I gather that BAW038 held for one circuit at LAM.
Added 'EGLL'

[pasoundman]

Oldlae
My concern is that whatever caused this incident may not have been recorded in the FDR because the relevant parameters have not been included


There was also a quick access recorder on this a/c. It will have been recording more data than the DFDR does.

[kuningan]

Great overhead image Some deductions from this:

It also appears that the disturbance of the ground differs between the right and left engine tracks - that could be because of different soil subsurface - or it could be because of differing power outputs - the Mail photograph suggests a lot of sandy soil being blown up on the lhs - reverse thrust?

[Dak Man]

Is it conceivable that the RH engine had already shut down and the approach was continued and subsequently the LH engine shuts down at 600' AGL and is still windmilling at impact.

The pictures of the turbo machinery seem to indicate such a scenario, i.e little or no fan damge to the RH engine and a contained fan blade separation of the LH engine.

So, the "failure" of both engine control systems may not have been a simultaneous event as previously speculated. Does this, once more, indicate a fuel starvation / contamination issue.

[OscarLimaIndia]

QAR's record less data, that's why they are QAR's

[Profit Max]

QAR's record less data, that's why they are QAR's:ugh:
Suggested reading (good description of a QAR):
http://www.tsb.gc.ca/en/reports/air/1998/a98h0003/01report/01factual/rep1_11_05.asp

[VnV2178B]

Overtalk,

I won't deny the possibility of a P30 problem, at this stage anything could be true, just wanted to point out that it is known and there is a mitigation strategy for it. Maybe the strategy doesn't work...

VnV

[Hand Solo]

QAR's record less data, that's why they are QAR's

Errrrr, no. QARs record much more data. They are QARs because they are not crash protected so you can get to the data Q.

[NSEU]

QAR's may have access to more data, but does that mean they necessarily record more data onto the PC card?

I thought the idea behind QAR's is that they could record bursts of selected information at selected points throughout the flight. i.e. stuff that maintenance/ops needed to know.

Of course, they can also be programmed to record additional data by unusual events (but will this be brief snapshots... or more useful continuous data?).

Does the QAR, DFDR and CVR run on the same elec (power) busses as the nose landing lights :confused: If so, we might get some pretty good info from one of these boxes :) .... Although, having said that, the AIM's system might not have been operating at 100% (considering the report that cockpit displays failed).

[r011ingthunder]

@NSEU who said, "Does the QAR, DFDR and CVR run on the same elec (power) busses as the nose landing lights"

I don't know, but I would assume that these devices would run on battery in the event of power outtages, after all what use would they be otherwise in recording data if the power went down?

[CargoOne]

I don't know what data is recorded on 777 QAR, but on our a bit older aircraft type where QAR was installed only through post-production SBs, QAR is basically recording 100% same data what is recorded on FDR. In fact both FDR and QAR are connected in parallel to the same data supply bus.
May be on a newer types where QAR is a standard equipment installed on production line, there are more options on what data you can record.

[SaturnV]

From a post by P2 earlier in this thread:
The QAR (for SESMA/FDM/FOQA work) will record as many parameters as the installed data frame is designed for, (QAR software) and at sample rates that the frame is similarly designed for. The DFDR is capable of this as well but typically DFDR data frames are smaller and at less frequent sample rates for many parameters. Sample rates of 16 frames per second are possible but are expensive in terms of storage and recording capability. Sample rates from once every fourth second to eight times per second are common in both DFDR and QAR dataframes.

All this is by way of clarifying that "700 parameters" and "2000 parameters" is not a fixed, determined number. Our own 777 QARS are taking in more than 2600 parameters (Bolding mine)

[hetfield]

17:1, which is about the same as the L/D of a modern airliner.

But not with gear and flaps extended.:bored:

[NSEU]

I don't know, but I would assume that these devices would run on battery in the event of power outtages, after all what use would they be otherwise in recording data if the power went down?

Never assume.. ;) I haven't got the relevant data with me for the 777, but all the other Boeings have these devices on the main elec busses. I can only imagine that this is because the designers think the pilots need the backup electric power more than the recorders. A competely flat battery will increase your risk of crashing considerably.

Would a windmilling fan be able to generate electrical power?

Not at approach speeds. A 747-400 pilot tells me that during cruise, a dead engine remained windmilling fast enough to provide proper power. "N2" or "N3" engine rotor speed (depending on the engine), has to be over 50% or so for the generators to produce power of a quality which will be accepted by the airplane.

Rgds.
NSEU

(Edit) According to the Maintenance Manual D&O, 115Vac power comes from the Right AC Xfr Bus, DC control power comes from the 28Vdc Main Bus. The Left Nose Landing Light uses the Left Xfr Bus and the Left 28VAC Main Bus... but no data as yet for the Right Nose Landing Gear light... but I'm guessing it uses the opposite busses... so the FDR will probably be getting good power.... but.. we should never assume ;)

[r011ingthunder]

@NSEU
I stand corrected then:ok:
Although there is no harm in assuming once you admit that's what you're doing!

[Busbert]

Based on the fact that there has been no advice from Boeing to other B777/T800 operators, it would suggest that there was some finger trouble or non-engineering failure in play.

The DFDR, CVR, QAR and the BITE/TSD from every relevant box on the aircraft will have been analysed by now. If there was an issue with the aircraft, we would have had all All Operator Wire, and probably an emergency AD by now.

The longer the silence continues, the more it looks like an operational issue.

[Magplug]

Busbert.... I, like you am a believer in simple causes for accidents and you are quite right - we would normally have seen some AD by now instructing operators to examine x,y,or x component.

However it is equally possible that there are a bunch of very clever AAIB guys who are still scratching their heads with absolutely NO idea what happened.

[SaturnV]

Magplug, I would not rate as equally possible that the AAIB is scratching its collective head in bewilderment. I think thats a small possibility at this point, given the extensive data thats available, the opportunity to interview the crew, and the ability to examine a relatively intact aircraft.

[Mad (Flt) Scientist]

With regard to the discussion about AD and Advisory Wire timings and what if anything can be deduced from the absence of the former.

I agree that it is likely that with the mass of data available that the investigators have a pretty good idea WHAT happened. What may very well be in doubt is WHY. Since an AD has to actually contain actions for the operators to take in order to assure or restore airworthiness, in the absence of a known cause there's nothing an AD can achieve, short of a mandatory precautionary grounding, which does not seem warranted at this point, since 777's are not falling out of the sky like leaves in autumn.

Even if the cause has been narrowed down to a single suspect piece of equipment, without knowing how to test for a repeat problem, there's little an AD could do.

[Fg Off Max Stout]

God help us! Never before have I seen so much uninformed bull being spouted.

This is exactly the reason that these threads will never die:

Post 302
The three Daily Mail photographs were of the same aircraft, so there was on very short finals AC power available (APU or main generators) to power the landing/ nosewheel lights.

Post 303
It looks to me that one of the DM photos is not of said aircraft - the landing lights are on!. Not something you would expect to see with a power failure and running on emergency power.

People with limited or zero aviation knowledge keep posting uninformed twaddle without bothering to read previous post and see that their half-witted pet theory was dismissed as ridiculous by those more likely to know on thread 1 page 1.

I have a reasonable amount of professional piloting experience on twin turbine multi crew aircraft, but because it is not on passenger jets I have so far bitten my tongue. I have some opinions about the accident but because of my lack of directly relevent knowledge I do not consider it appropriate to start arguing the toss - a fact that should be considered by all the taxi drivers, flight simmers, school kids etc who are clogging up the website. It was laughable initially but now it's a pain in the arse and just the sort of thing that could make PPRUNE restrict its membership to Pro Pilots only, which would be a shame.

Amongst my favourites so far include:

B777 avionics run on Microsoft Windows so someone with a laptop used wifi to hack into the autopilot and cause the crash.
There was no avgas in the tanks.


Sorry to be harsh but if you know virtually nothing about aviation then your opinion on this subject is worthless and simply a waste of bandwidth. Rant over!

My money is on a software snag and I have experienced numerous FADEC failures in the past that have resulted in OEI flight in a twin. However, in the poll I voted for alien intervention to illustrate the futility of these theads. I know nothing of significance about trains or ships, and next time there is a rail or shipping accident I will STFU. Others take heed.

[G-ZUZZ]

I fly the B777. I'm a little dismayed by the rot being posted here but since some people are focussing on the A/T system, here are a few facts:

The levers MOVE with power changes about as much as in a B737 or B757 or B767.
The pilot can feel (and see) the levers move.
If the aware pilot knows he needs more thrust and the levers aren't moving, it IS obvious by the lack of movement, among other indications.
If the A/T system is over-ridden by moving the levers and then the hand-pressure is removed, the levers will return toward their orginal positions and attempt to maintain the commanded speed but only when in a SPD mode.
In the HOLD mode the levers will stay wherever you leave them, with associated thrust levels.
During approach the A/T system is normally in SPD mode unless manual speed/thrust control is being employed by the pilot.
FADEC is a separate system for each engine and should not automatically be blamed here.
The Boeing operating manual for the 777 is very light on for detail and about 10% of the thickness of what I would probably need to offer a reasonable opinion on why both engines failed to do perform as advertised so, in an apparently unheard-of move around here, I will not put forward a half-arsed theory.
Nothing regarding thrust delivery can be determined with absolute certainty from the photos of the engines. The theories and postulations going around here are laughable.
With loss of electrical power to the Transfer Buses, the APU would attempt to start automatically even on the ground. This involves the intake door opening. Whether it achieved this successfully in the case of BA38 cannot be determined from the photographs.
The RAT door, if indeed it is open, may have opened due to damage sustained during the impact and subsequent ground "roll".
600ft/2NM is on glideslope but is not, in my opinion, enough time to recover from the overhelming surprise, remember the passengers, look down select a PA option and blurt a "Brace, brace" command to a bunch of people who will probably not understand the rapid-fire noise anyway. It would obviously be beneficial to have done so but I suspect many crew would've suddenly found themselves in a state of task-saturation and be focussing on the real job. Not much point in warning pople if it costs the opportunity to maintain control of the aircraft.
There is only one final approach per runway, therefore the aircraft was on short final, not finals.
Three final points:

1. Nothing conclusive about the cause of the event can be determined form the photographs.

2. The majority of idiotic posts here is something I try to laugh at but somehow I just can't quite.

3. And finally, may I add that ATC had runway 27L back in use for intersection departures within a very short space of time, considering - about 90min or so, possibly less. Meanwhile they dealt very successfully and professionally with a vast number of movements and only one runway at times, in addition to weather (more closures not long after re-opening the field) and the late discovery that the runway edge lighting was unserviceable, with last light not far away.

A big well-done to the ATC crowd at London Heathrow. Well done, guys...!! :D :ok:

[woodpecker]

Thanks "Fg Off Max Stout" for quoting my comments following your statement..

God help us! Never before have I seen so much uninformed bull being spouted.


If you know Heathrow you would know where the approach picture was taken from. Are you saying the second and third pictures of the touchdown and evacuation are not of "MM", of course not. So why with the "fortunate" photographer there at the time with his camera at the ready would he not "snap" a 777 far too low at a greater attitude than normal?

Of course the picture is correct.

If, however you were agreeing with my comments and disagreeing with those that followed then I apologise.

The six years that I flew the B777 never had a FADEC failure, but as you know FADEC as such doesn't exist so perhaps I should have said EEC failures!!

[Flap 5]

Having read through (most of) the thread there is some good information here as well as some rubbish. I am not 777 qualified being just a humble A330 / A320 / B737 pilot however there may be one item which has not been considered. If both engines had failed and were windmilling they would produce considerable drag (having large fans), increasing the glide angle and losing more energy than if the engines were under idle power.

[Fg Off Max Stout]

Woodpecker don't worry, your points seem undisputable. I merely juxtaposed your quote with a quote from the following post to illustrate the absurdity of these threads. Your post answered a question that was then asked by the following poster. Clearly he had launched in with his own opinions without reading any of the preceding thread, not even the post immediately before his own. This is why these threads will go around in circles until they implode, taking everyone's sanity with them.

Fortunately many of the less 'highbrow' posts in this thread have been, quite literally, pruned.

[sevenstrokeroll]

ok

there was fuel on the plane, in the plane, in the tanks. I don't doubt that.

No one has yet to use the word: starvation, instead of exhaustion.

I don't even believe that it was starvation or exhaustion...but we can have fuel leaking all over the place, and it might not have gotten to the engines.

again, I don't think that is what happened. But at least let us use the right terms.

exhaustion: no more fuel period (useable)

starvation: fuel on board, but not getting to the engines.

[skol]

I havre to say after all this time, considering the aircraft was parked intact almost outside the hangar that as above, speculation will become worse as time goes on and that investigators must know the cause of the accident now.
More knowledgable SLF, especially frequent flyers will be avoiding 777's.
Some have noted that there was fuel in the tanks but there will always be some unusable fuel. The procedures for the type I fly (744) states in the notes for EICAS msg Fuel Qty Low, "Avoid high nose up attitude and excessive acceleration and deceleration".

[Croqueteer]

I hate to bring this up as a mere Quadrapuff pilot, (Retired) and I admit to not having seen every entry to this thread, but when presumably the auto pilot tried to follow the G/S, a pretty quick speed decay would be seen, which I would react to by disconnecting the autopilot and lowering the nose. This would allow some alfa left to arrest the rate of sink, which must have been excessive to stuff the gear through the wing. It would also possibly give another couple of hundred yards to the touchdown point. I say this as over the years I have been close to some total engine failures which have had successful outcomes ( No fatalities) due to the crew keeping the aircraft under control and landing with flying speed.

[Lost in Saigon]

Surely the most probable cause that can be deduced from the available information is that the engines were on straight feed and whilst there was fuel remaining it was asymetric - all on one side. Thus one engine was starved and ran down at about 600 feet.

You now have a heavy twin, gear down, one engine out, landing flap already selected, approaching at Vref plus a bit and two miles to the threshold.

what on earth do you think is going to happen next?


What happens next? Easy......

You call "Go Around, Flap 20", followed by "Positive Rate", and then "Gear Up".

Then you monitor the autopilot while the B777 merrily starts climbing away on one BIG FAT ENGINE! (110,000 lbs thrust)

OR.....

Add just a little bit of thrust to the good engine and land.

[HarryMann]

1 degree nose down (less than you could detect in a picture) from the 600' where the problem starts = impact 1NM short... :{ They got to well less than 1/2NM short... so I am not sure your "they should have lowered the nose" is exactly what the AAIB will write about :ugh:

Wrong Nigel ...

Not only have you got your sums wrong (1 deg over 1nm is almost exactly 100 ft in altitude), you also have the theory wrong too, as the actual glide angle would like as not improve if you're already on the back of the drag curve... which again, like as not, they were by then.

Your 1001st post doesn't exactly augur well for the future of considered and knowledgeable comment here :=

[mbd]

Quote:
The investigation is now focussed.. ..examining the range of aircraft systems that could influence engine operation.

I'm sure B777 pilots are sleeping well tonight.

Quote:
Following further demands for increased thrust.. ..the engines similarly failed to respond.

Lack of fuel will do that. Like I said it is all speculation, but what is most likely?


Quote "The real answer to that question is why don't you become a pilot and find out? :ugh: "

Cheap shot, you really shouldn't jump to conclusions now should you?:)

[NSEU]

Just to show you how complex a system it is, I have included a description of the B777 EEC System with General Electric engines: (note: BA 777's have RR Trent engines, but they are probably similar)

Electronic Engine Control (EEC)

Each EEC has full authority over engine operation. The EEC uses thrust lever inputs to automatically control forward thrust and reverse thrust. The EEC has two control modes: normal and alternate. In both normal and alternate modes, the EEC uses N1 RPM as the parameter for setting thrust.

Probably similar, but not ;) Trents use EPR as the primary parameter.

Sorry, I couldn't read the rest.. the red print is too hard on the eyes.... :8

[Wayne Ker]

I think there has been enough chit chat about this incident, people are getting more and more extreme with wild ideas about what did or didnt happen. The AAIB have got an almost pristine aircraft to pick over, no fire etc to muddy the waters, I should think for them, it will be fairly straight forward to gather the facts.

I know it is asking the impossible but why don't we wait until the report is out and give the crew of the aircraft a bit of space to breath and recoup. We do not have the facts and wild speculation is no good for anybody.:ok:

[sky9]

Some interesting photographs from flightglobal
[URL="http://www.flightglobal.com/AirSpace/photos/baboeing777accident/ba_2D00_boeing_2D00_777_2D00_incident_2D00_at_2D00_heathrow-8122.aspx"]

[borghha]

Just a SLF here, but a long standing PPrune reader.

It struck me that the FAA report and AD on the 777 EPR sensing probes and - lines (GE engines, ok) almost predicted this crash. ('could lead to loss of control of the a/c in a critical flight phase') - Does anybody know whether RR engines are that different in this respect? Someone wrote that other engine manufacturers would 'look away' when such an AD goes out... I can hardly believe that, given the stakes. Wouldn't they have checked whether their probes/sensors were vulnerable (icing) in that respect too?

Fly safely.

[7x7]

Haven't read all 18 pages, so apologies if this point has been covered already, but can I have a quick show of hands to see how many captains out there would allow their FO - however experienced - to continue flying the approach and landing in a situation like this?

600' is 2 miles out. I don't think I'd be mentally capable of sitting back and continuing my PNF duties (or whatever it is BA with their rather unique system of PF/PNF call it). You're the captain, and if he doesn't do it exactly the way you want it done, in a no power situation like that, there's no recovering whatever his (in your mind) not quite appropriate actions might have lost you.

[flypy]

7x7 don't be a prat.

Proper CRM would involve both pilots working in the very very short time available to try and resolve the problem, not squabbling over who has official control over the aircraft. In these times, working to SOPs and working together are significantly more important than who has more bars on their shoulder.

600' and 2mls may not sound like much, but if you lost ALL power in a 777 you can bet your arse that 0' would be rushing up to meet you pretty bloody quickly.

[ACMS]

7X7: good question, I've thought about and I can honestly say it would depend who the F/O was. A high 777 time Senior F/O that was handling the aircraft ok in the situation I would let him continue and help if necessary.
With a low time inexperienced F/O on the 777 I would probably take over.


I'm certainly not going to sit there and watch anyone stuff it up.

Sticking to SOP's would be a good start.

[aviate1138]

AAIB has issued a report on an Airbus A319-131 which had electrical problems departing EGLL/LHR in 2005 - 22 Oct.

That aircraft [crew did their job within 90 seconds] continued its flight and presumably was examined as thoroughly as the BA 777 is being right now.

It seems with anything electrical as opposed to mechanical there are few electronic 'witness marks/structural damage' results when electrons are involved. Except in some cases burnt wires and boxes.

AAIB Report No: 2/2008 G-EUOB
There is a significant paragraph in that states in part,

"It was not possible to determine the cause of the incident due to a lack of suitable evidence..."

Will there be a similar result with the 777 as all the evidence is presumably at hand, FDR stuff etc?

Might be a long wait for a certain conclusion - if ever.

[Seloco]

So far the only thing that we know, FOR CERTAIN, is that, whenever we get the eventual outcome of the investigation, MANY PEOPLE on this thread should be eating humble pie and SOMEONE may be able to say "I told you so", PERHAPS!

[Bobbsy]

Dream Land, let me speculate as to why people are so annoyed by speculation:

First, I doubt many people are too worried about well-informed speculation; it's the contradictory rubbish that is getting on people's nerves, especially when it's stated as fact.

We've seen the same photos supposedly proving the engines WERE turning and WEREN'T turning, that the RAT was out and working or not extended at all, people who have never been on a 777 flight deck explaining (incorrectly) the working of the auto-throttle system and so on.

Second, it's well known that the media read this forum to feed their insatiable need for information, accurate or not.

Combine these two issues and I can see why all the speculation is a sore point.

Bobbsy

[Albert Square]

Has anybody noticed that the AAIB have issued a second report on this incident?

[NigelOnDraft]

Suggest Mods close this thread in light of "update to Initial" AAIB" report ;) And start a new one... Will shut some of the crack pots up :{

[Danny]

Please see new thread in light of updated AAIB interim report.

Some of the less informed speculation will hopefully die down. Anything deemed too lowbrow will be moved to the WAG's (Wives & Girlfriends) thread in Jet Blast where the pretenders can battle it out with the other assorted conspiracy theorists and anoraks. :ugh: