BA B777 Incident @ Heathrow (merged)
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To helldog, that is exactly my point. If you loose all power the only thing you have left is to trade speed for lift and you squeeze it out as skillfully as you can by pulling on the elevator and keeping those wings as level as possible, hopefully running out of lift just as you touch down. If that was the case and nobody knows yet, they did an awesome job as you never parctice that in the sim, just seat of your pants flying!
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Not a clue !
As an ATPL & Maintenance engineers licence holder I have seen the news reports and 14 pages above.
At the moment I could not say with any reliability what the cause of this incident was, about the only thing written above that I would agree with 100% is that we should wait for the AAIB report before speculating further.
However nothing that I say will stop the rubbish that is being spouted by the so called avition experts.
At the moment I could not say with any reliability what the cause of this incident was, about the only thing written above that I would agree with 100% is that we should wait for the AAIB report before speculating further.
However nothing that I say will stop the rubbish that is being spouted by the so called avition experts.
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10%: "I think all this speculation is disgraceful, everyone please shut up."
10%: "Cud it be maybe the pilut fell asleep and the wheels fell off ?"
TV News: "We are getting reports that the pilut fell asleep allowing the wings to fall off"
80%: "I think all this speculation is disgraceful, but.... <huge amount of speculation>"
This place never changes.
10%: "Cud it be maybe the pilut fell asleep and the wheels fell off ?"
TV News: "We are getting reports that the pilut fell asleep allowing the wings to fall off"
80%: "I think all this speculation is disgraceful, but.... <huge amount of speculation>"
This place never changes.
Firstly, congratulations to the crew for making such a successful forced landing that everyone survived with only a few minor injuries reported. Indeed, some passengers didn’t even know they’d been in a crash. The evacuation appears to have been copybook; perhaps that alone fully vindicates the airline’s policy of cabin crew salary scales which encourage ‘career’, highly professional, cabin crew?
Regrettably, there has been a lot of nonsense posted on this website and sifting through the garbage has taken quite a time. Thanks to those who provided factual description of the forced landing, that alone has narrowed the possibilities. Drunken aussie pranskters and off-the-wall wild-ass-guesses haven’t helped.
PJ2, I think your line of investigation is very probably close to the mark. Has it yet been established whether the engines were at idle thrust – or had flamed out. In very gusty conditions, if the automatic throttle system (sorry, I don’t know the Boeing term) detects – for whatever reason – a significant excursion well above the target speed, how much authority does the system have and is the gain rate sufficient to command both engines to idle thrust at a rate which might be difficult for the crew to react to in the last few moments of a very long flight? If the engines were commanded to idle thrust at 400 ft in an unusual weather situation, how long does it take to take over manually and recover the situation in unpredictable, gusty conditions?
These are questions, NOT speculation.
Again, very many congratulations to the crew for their highly professional actions.
Regrettably, there has been a lot of nonsense posted on this website and sifting through the garbage has taken quite a time. Thanks to those who provided factual description of the forced landing, that alone has narrowed the possibilities. Drunken aussie pranskters and off-the-wall wild-ass-guesses haven’t helped.
PJ2, I think your line of investigation is very probably close to the mark. Has it yet been established whether the engines were at idle thrust – or had flamed out. In very gusty conditions, if the automatic throttle system (sorry, I don’t know the Boeing term) detects – for whatever reason – a significant excursion well above the target speed, how much authority does the system have and is the gain rate sufficient to command both engines to idle thrust at a rate which might be difficult for the crew to react to in the last few moments of a very long flight? If the engines were commanded to idle thrust at 400 ft in an unusual weather situation, how long does it take to take over manually and recover the situation in unpredictable, gusty conditions?
These are questions, NOT speculation.
Again, very many congratulations to the crew for their highly professional actions.
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Beagle:
B777's Thrustlevers move! Thank god for that.
As the PF's hand will be on the throttles, he/she will know if the autothrottle is powering back without looking at the instruments.
Muscle memory will give him/her ample warning. After that it is just a matter of stopping the levers coming back to idle and as thrust is allways relevant to powerlever angle it will stop decaying. If you need more thrust just push them back up. No big deal.
B777's Thrustlevers move! Thank god for that.
As the PF's hand will be on the throttles, he/she will know if the autothrottle is powering back without looking at the instruments.
Muscle memory will give him/her ample warning. After that it is just a matter of stopping the levers coming back to idle and as thrust is allways relevant to powerlever angle it will stop decaying. If you need more thrust just push them back up. No big deal.
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Dont worry, it's just management pilots having a crack at their minimum fuel policy. Note to self, continue to disregard company minimum fuel policy!
Not so much of a speed bird as a stuffed duck
Not so much of a speed bird as a stuffed duck
ENTREPPRUNEUR
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At least two witnesses - one a passenger - report the engines were racing or sounding like take-off. Why is everyone ignoring this?
Also:
As is most of these cases the flight crew didn't (couldn't) do anything that wasn't utterly straightforward ie choose a speed, keep flying and pray.
Also:
Prime Minister Gordon Brown, who is on a visit to China, has praised 43-year-old pilot Peter Burkill's "professionalism" for managing to avert a major disaster.
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Annex 14, CAP 168 and aerodrome safety design
Lots of speculation, it's a rumour site, after all!
However, one aspect is apparent already; the design of the various protected slope surfaces, runway Strip and Cleared and Graded Area (CGA), Runway End Safety Area (RESA) and other aerodrome criteria has in this case proven to be entirely adequate. These distances/dimensions have been arrived at over the years by expeience with other accidents and incidents (I personally recall the Continental B747 getting rather too close to the South Terminal roof at LGW). Have a look in CAP168 for a lovely diagram bringing all the surfaces together; it looks a bit like a sports stadium with the runway on the pitch.
Recently, ICAO recommended that RESA be increased from 90M to 240M, good call!
Although the CGA has a 'neck' 75M either side of the Centreline at the runway ends, the Strip is still 150M and the closest holding point must be 90M from the Centreline. These figures for a Code 4 Instrument runway, which is what 27L is, of course. In this case the a/c slewed as it changed from one surface to another but a vehicle or aircraft holding at NB1 would have been OK.
Another aspect of aerodrome design that no-one ever sees is protection for undercarriage running in the soft, encountering the edge of a runway or taxiway. An underground ramp is constructed at all transitions to allow wheels to ride up onto the hard, instead of the gear being wiped off by a vertical surface. Unfortunately the main gear in this case was already destroyed but it does appear that the noseleg, although compressed into the fuselage, might well have ridden up the ramp. This safety provision is known as 'Delethalisation'.
Now, Public Safety Zones, there's a whole new topic!!
TheOddOne
However, one aspect is apparent already; the design of the various protected slope surfaces, runway Strip and Cleared and Graded Area (CGA), Runway End Safety Area (RESA) and other aerodrome criteria has in this case proven to be entirely adequate. These distances/dimensions have been arrived at over the years by expeience with other accidents and incidents (I personally recall the Continental B747 getting rather too close to the South Terminal roof at LGW). Have a look in CAP168 for a lovely diagram bringing all the surfaces together; it looks a bit like a sports stadium with the runway on the pitch.
Recently, ICAO recommended that RESA be increased from 90M to 240M, good call!
Although the CGA has a 'neck' 75M either side of the Centreline at the runway ends, the Strip is still 150M and the closest holding point must be 90M from the Centreline. These figures for a Code 4 Instrument runway, which is what 27L is, of course. In this case the a/c slewed as it changed from one surface to another but a vehicle or aircraft holding at NB1 would have been OK.
Another aspect of aerodrome design that no-one ever sees is protection for undercarriage running in the soft, encountering the edge of a runway or taxiway. An underground ramp is constructed at all transitions to allow wheels to ride up onto the hard, instead of the gear being wiped off by a vertical surface. Unfortunately the main gear in this case was already destroyed but it does appear that the noseleg, although compressed into the fuselage, might well have ridden up the ramp. This safety provision is known as 'Delethalisation'.
Now, Public Safety Zones, there's a whole new topic!!
TheOddOne
Fly Conventional Gear
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At least two witnesses - one a passenger - report the engines were racing or sounding like take-off. Why is everyone ignoring this?
It would explain both the 'roaring' and the 'loss of power'.
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Once again, in order to try and quell some of the uninformed specualtors, engines losing thrust do not necessarily have to be "silent" or shut down! As long as they are unable to provide the commanded thrust or the necessary thrust to overcome the drag to maintain the flight profile then you have a significant problem.
So, would the speculators who have very little obvious idea of what is involved, please sit back and read rather than postulate with obvious lack of understanding! We need all the bandwidth we can get at the moment!
A Trent engine, even at idle power will sound like it is "roaring" if you are standing close enough!
So, would the speculators who have very little obvious idea of what is involved, please sit back and read rather than postulate with obvious lack of understanding! We need all the bandwidth we can get at the moment!
A Trent engine, even at idle power will sound like it is "roaring" if you are standing close enough!
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The RAT is deployed automatically if both AC transfer busses lose power in flight. The RAT can be manually deployed by pushing the RAM AIR TURBINE switch on the overhead panel.
RAT deployment logic includes airspeed or groundspeed, air-ground, engine below idle, time delays. etc. Loss of power to the Left and Right Transfer (Electrical) Busses also autostarts the Auxilliary Power Unit.
The RAT deploys in 2 seconds after the logic has been satisfied, but will obviously take a few seconds to get up to full operating speed.
The 777 is most definitely Fly-By-Wire. Don't be fooled by the traditional-looking control wheels.
Re the flickering of lights.. If AC power changes sources in the air, there is a "break power transfer", so the lights might flicker. There may also be automatical loadshedding disturbing the electrical system.
Regards.
NSEU
P.S. I think a Malaysian Airlines 777 had an uncommanded thrust reduction (but I thought the manufacturer fixed that problem with new software).
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The next rumor from The Sun suggests some autopilot/autothrottle glitch and also alledges that a mayday was broadcast:
It appears an alledgedly similar incident has happened to a B777 before in 1995 (summary, full report) due to false accelerometers readings and failure detection logic.
This incident ending in a successful landing is not the "multiple-death crash 15 years ago" referenced by The Sun.
Just offering this to discussion, not in any way supporting or endorsing the theory. Instead I think at least the claim that emergency comms were initiated is not credible, because we should have heard this from a lot of other sources if it was true.
Originally Posted by By NICK PARKER, JAMIE PYATT, ALEX PEAKE and VIRGINIA WHEELER of The Sun
Insiders said inquiries were focusing on an unexplained “involuntary flight control command” initiated by the jet’s computer.
The on-board system is thought to have pulled the plane’s nose skywards as it began its descent.
At the same time, it is said to have throttled BACK the engines.
Only one other similar fault has ever been recorded - and resulted in a multiple-death crash 15 years ago.
The on-board system is thought to have pulled the plane’s nose skywards as it began its descent.
At the same time, it is said to have throttled BACK the engines.
Only one other similar fault has ever been recorded - and resulted in a multiple-death crash 15 years ago.
This incident ending in a successful landing is not the "multiple-death crash 15 years ago" referenced by The Sun.
Just offering this to discussion, not in any way supporting or endorsing the theory. Instead I think at least the claim that emergency comms were initiated is not credible, because we should have heard this from a lot of other sources if it was true.
Last edited by EFHF; 18th Jan 2008 at 10:12. Reason: Adding links
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I know I really shouldn't post, SLF sorry, but a few people have said about the supposed eye witness reports of engine roaring.
Seems people have said if the RAT was out (does not seem clear if it was or was not) it is bloody noisy. Could that account for the noise they may have heard?
Seems people have said if the RAT was out (does not seem clear if it was or was not) it is bloody noisy. Could that account for the noise they may have heard?
I Have Control
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Single-engine failure? Low down, low thrust, gusty cross-wind, down-draught/windshear.....could be tricky for the A/THR and PF to handle. Might explain steep bank angle and noise from one engine. I know, I know, this shouldn't cause an undershoot of such proportions, and this is mere speculation. Hope fully all will be revealed from the FDR and CVR.
Well done, BA crew and emergency services. Quick and positive response.
Well done, BA crew and emergency services. Quick and positive response.
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Inset thresholds/aiming points
A couple of years ago it was proposed that the 27L/27R thresholds and aiming points be inset by around 500M to raise the approach slightly and reduce noise impact. 27R in particular has excess landing distance available over requirement for all types.
Perhaps the time has arrived to review this idea from a safety case point of view rather than an environmental one?
TheOddOne
Perhaps the time has arrived to review this idea from a safety case point of view rather than an environmental one?
TheOddOne
Single-engine failure? Low down, low thrust, gusty cross-wind, down-draught/windshear.....could be tricky for the A/THR and PF to handle. Might explain steep bank angle and noise from one engine. I know, I know, this shouldn't cause an undershoot of such proportions, and this is mere speculation. Hope fully all will be revealed from the FDR and CVR.
A single engine failure at that stage of flight is irrelevant. Even from a autopilot/autothrottle point of view.
I specifically remember being in the simulator for my conversion training to the B777, and the instructor gave me an engine failure at 500 feet, on short final. The autothrottle and autopilot were engaged, because the weather was Cat III. result? uneventful landing, autoland.
Conclusion: a single engine failure at 500 feet is more or less irrelevant, and will not make a whole lot of difference.
Also, a single engine failure will not any handling difficulties. The 777 is always in trim. As long as the airspeed remains the same before/after the single engine fails, the airplane is still in trim. there is an automatic trrim system installed. so no handling problems there. Furthermore, the autothrotlle is very "agressive" and will react firmly to the single engine not providing any thrust. It only needs to add about 7% N1 to compensate anyway on a 3 degree glidepath.
Last edited by fox niner; 18th Jan 2008 at 09:46.
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Trouble at the end of a long flight...
The comment about Vref and adding extra for the conditions reminds me of my "hoary" old Lanc pilot who said that after a long flight into enemy territory - and don't forget only one pilot on the Lanc - if the weather was even slightly unstable it was "add 5 knots for the wife and 5 for each child"
He said he thanked himself for that reminder on several occasions. (I am not suggesting anybody does this and ignores the manual!)
What concerns me quite a little about this incident is that a PPL reported a steep rate of bank on late finals. That does not suggest engine failure but abnormal airflow i.e. shear, violent gusting etc. Any comments?
He said he thanked himself for that reminder on several occasions. (I am not suggesting anybody does this and ignores the manual!)
What concerns me quite a little about this incident is that a PPL reported a steep rate of bank on late finals. That does not suggest engine failure but abnormal airflow i.e. shear, violent gusting etc. Any comments?