BA B777 Incident @ Heathrow (merged)
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I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK?
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Boeing rebuild
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
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
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JenCluse
This lad's approach seems a fairly similar example of such a technique. Comments?
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.
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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.
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.
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It has been registered as "destroyed" on www.atdb.org which has proved fairly reliable in the 2 years I have used it.
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Alerting Cabin Crew
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.
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.
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Stretching the glide
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.
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.
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Bumpy landing?
By all accounts the pax thought it was a normal bumpy landing.
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.
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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.
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%!
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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
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
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Hands up
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.
The silent heroes.
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?
Does TAT probe icing ring any bells for anyone?
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I wonder if Boeing will pay to patch her up as opposed to writing her off, as with the QF 747 in BKK?
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paulthornton -- stretching the glide
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.
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BBC Article
This from the BBC site makes more sense than the pages of drivel I've read here. Go figure!
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:
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.
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:
- [*]
- [*]
- [*]
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.
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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.
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.
Last edited by nigegilb; 19th Jan 2008 at 15:34.
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Pilot Talks
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
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
Last edited by sandbank; 19th Jan 2008 at 15:43.
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More (unsubstantiated) speculation
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.
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.
