Thursday, 17 January 2008
A British Airways plane crash-landed at Heathrow Airport on Thursday afternoon. Media reports say the pilot lost all power late in his approach and had to glide down to the runway. He failed to reach the runway by several hundred metres, narrowly skimming over the airport's perimeter road. No souls lost!!!
An airport worker told the BBC the Boeing 777 pilot, named later as Peter Burkill, 43, said he had lost all power and had to glide the plane in to land. The worker also said the pilot had told him all the electronics had also failed. "He said he had no warning - it just went," the worker added. "It's a miracle. The man deserves a medal as big as a frying pan."
http://news.bbc.co.uk/2/hi/uk_news/engl ... 194086.stm
BA plane 'lost power' before crash landing at Heathrow
Airplanes systems today have multiple levels of redundancy; however, some electronics going offline could be the result of engine driven generators going offline (there are often multiple gens per engine, APU driven gens, batteries, backup batteries, airflow driven emergency gens etc). Hydraulics are typically engine driven also with electric backup pumps, and ultimately manual reversion which means you command the control surfaces without hydraulic assist. Throttles in older birds are quite different from modern designs that are often use Fly-by-wire and/or Full Authority Digital Engine/Electronic Control (or FADEC) input. Again, an electrical emergency wouldn't cause an engine failure or vice versa; an engine failure wouldn't directly cause an electrical failure. For aircraft equipped with FADECs, each engine has multiple electronic control units that need to agree with each other. One unit is in charge, the other in standby mode/monitoring mode and generally speaking, the engine wouldn't shut down unless there's a complete loss of FADEC signal(s) from all units. Each engine is also independent from other engine's FADECs. This gives you a slim insight into the levels of redundancy today's aircraft have, so this accident (as described in the news media) is quite "unheard of"...
What happened at Heathrow - who knows? Each airplane is unique in its design, but they when it comes to this accident one thing in common: What happened here is baffling (!), unless it's a chain event of things (always the case) and/or pilot error (!)... and I'm not trying to point one way or the other, still given the results, the crew did an amazing job keeping the plane intact and saving the lives of over a hundred people. The investigation will surely look into every aspect, not just mechanical, but human factors as well.
What happened at Heathrow - who knows? Each airplane is unique in its design, but they when it comes to this accident one thing in common: What happened here is baffling (!), unless it's a chain event of things (always the case) and/or pilot error (!)... and I'm not trying to point one way or the other, still given the results, the crew did an amazing job keeping the plane intact and saving the lives of over a hundred people. The investigation will surely look into every aspect, not just mechanical, but human factors as well.
A dual engine failure? When's the last time that happened? I'm gonna guess (and the authorities are free to prove me wrong) that it was fuel starvation or contanimation. The odds of accidently shutting down both engines are like a billion to one. The odds of failure in one engine is long (but it happens), twice really long, and both at once is... impossible?
There is a third possibility. Bird strike. But let's just say that both engines got FODed out by birds. Would they spool down that fast?
DISCLAIMER: I dunno why, but I'm breaking my "We don't have all the facts" rule. I shouldn't, but I am.
There is a third possibility. Bird strike. But let's just say that both engines got FODed out by birds. Would they spool down that fast?
DISCLAIMER: I dunno why, but I'm breaking my "We don't have all the facts" rule. I shouldn't, but I am.
Speculation on a forum like this is harmless.
My two cents.
Fuel Contamination in Beijing.
Known facts:
*The flight was uneventful until 600 feet on approach when both engines lost power. No Mayday or Low fuel advisory was issued before this point so this indicates the crew thought they had sufficient fuel to land safely with reserves. BA pilots are well-trained and if they thought they were runnng out of fuel they would have told someone or diverted long before this point.
*The aircraft autopilot and autothrust system were coupled to the ILS when the power loss occurred. A youtube video taken just after that point shows the aircraft in a high nose attitude consistent with the autoflight system attempting to stay on the glideslope after the engines failed. (How close did this aircraft come to a stall at that point?)
* At this point the pilot flying disconnected the autopilot and lowered the nose to attempt to glide to the field. There is some evidence that one of the engines autostarted prior to the aircraft coming to a halt just short of the runway.
As pointed out before, simultaneous dual engine failures just don't happen. On the 777, the ONLY common factor is the fuel. The engines operate independantly with different FADEC's and FADEC batteries. The 777 even has separate autothrust systems for each engine. There is also evidence of a large amout of fuel leaking from the wings after landing.
Ergo, they had fuel.
This really only leaves fuel contamination as the likely culprit. On a side note here we have already seen the CEO of BA publicly thanking and applauding his crew. Airline managements are not stupid, they know pretty quickly if the crew has screwed up and that simply would not have happened if the crew had run the aircraft dry.
I would wager we are going to see a flurry of activity in the next day or so about checks on the quality of fuel out of China.
My two cents.
Fuel Contamination in Beijing.
Known facts:
*The flight was uneventful until 600 feet on approach when both engines lost power. No Mayday or Low fuel advisory was issued before this point so this indicates the crew thought they had sufficient fuel to land safely with reserves. BA pilots are well-trained and if they thought they were runnng out of fuel they would have told someone or diverted long before this point.
*The aircraft autopilot and autothrust system were coupled to the ILS when the power loss occurred. A youtube video taken just after that point shows the aircraft in a high nose attitude consistent with the autoflight system attempting to stay on the glideslope after the engines failed. (How close did this aircraft come to a stall at that point?)
* At this point the pilot flying disconnected the autopilot and lowered the nose to attempt to glide to the field. There is some evidence that one of the engines autostarted prior to the aircraft coming to a halt just short of the runway.
As pointed out before, simultaneous dual engine failures just don't happen. On the 777, the ONLY common factor is the fuel. The engines operate independantly with different FADEC's and FADEC batteries. The 777 even has separate autothrust systems for each engine. There is also evidence of a large amout of fuel leaking from the wings after landing.
Ergo, they had fuel.
This really only leaves fuel contamination as the likely culprit. On a side note here we have already seen the CEO of BA publicly thanking and applauding his crew. Airline managements are not stupid, they know pretty quickly if the crew has screwed up and that simply would not have happened if the crew had run the aircraft dry.
I would wager we are going to see a flurry of activity in the next day or so about checks on the quality of fuel out of China.
Got a link?TWC_Cobra wrote:A youtube video taken just after that point shows the aircraft in a high nose attitude consistent with the autoflight system attempting to stay on the glideslope after the engines failed. (How close did this aircraft come to a stall at that point?)
There are dozens of news coverage clips, press conf. with the flight crew on YouTube, but finding anything showing the final moments seems a bit harder.
Youtube has taken off all videos of that approach, dunno why
...and after a lot of time of searching, the longest one I could find of it was 7 seconds, but better than nothing...
http://www.megavideo.com/?v=0KHTNGHS
...and after a lot of time of searching, the longest one I could find of it was 7 seconds, but better than nothing...
http://www.megavideo.com/?v=0KHTNGHS
If it had been fuel contamination though, I am sure they would have known about it well before they were on short final? Something doesn't quite add up here.
I'd throw the bird speculation out the window as well, most major airports do a good job of keeping the bird populations quelled around the airport. Plus, if there had been bird damage, there would have been fire coming out of the engines and we would have heard of it by now.
I'd throw the bird speculation out the window as well, most major airports do a good job of keeping the bird populations quelled around the airport. Plus, if there had been bird damage, there would have been fire coming out of the engines and we would have heard of it by now.
Phantoms Phorever!
Despite what the guy is saying, the nose is actually a lot higher than what it should have been at that stage, particularly with the reported headwind.
Rhino, jet engines can actually take a bit of water in the fuel with no ill effects. At the end of the flight however, with the fuel temperature at around -30C and only a fraction of the normal fuel remaining, it is possible that they had a normal fuel feed until enough ice formed to cause a problem, or it may have been that the fuel was contaminated by something else that wasn't supposed to be in there; something that wasn't ingested into the fuel system till the level in the tank reached below a certain figure.
The aircraft landed with 5 tonnes of fuel in each tank, about normal for a 777.
I have no doubt the investigators will find whatever the culprit was.
Thanks for the link(s). Gotta love the reporter insisting the plane looks low in relation to the lights and then the "expert" trying to explain "optical projection" to her in his nicest way; unless you know the relative angle and location between the observer and the plane it really doesn't tell you anything there reporter lady! 
(Of course, most around here would understand "optical hits" given their frequent utilization in air shows).
Looked to me like the nose was really high in the final frames they showed and if I had to guess, fuel additives/contamination sounds like a highly likely cause. It also reminds me of the A320 "Fly-by" crash several years back when the engines wouldn't give the pilots the commanded thrust for the go-around....
P.S. It will be interesting to see what the investigation reveals. Had they missed the clearway about 100ft short, this story would have been headline news coverage on the "Fireball at Heathrow", now seems as if any causes to this accident won't even make the 6 o'clock news.
...and Cobra, those ALS lights are priceless!
(Of course, most around here would understand "optical hits" given their frequent utilization in air shows).Looked to me like the nose was really high in the final frames they showed and if I had to guess, fuel additives/contamination sounds like a highly likely cause. It also reminds me of the A320 "Fly-by" crash several years back when the engines wouldn't give the pilots the commanded thrust for the go-around....
P.S. It will be interesting to see what the investigation reveals. Had they missed the clearway about 100ft short, this story would have been headline news coverage on the "Fireball at Heathrow", now seems as if any causes to this accident won't even make the 6 o'clock news.
...and Cobra, those ALS lights are priceless!
I tend to avoid early comments not because of liability (none of us have inside information), none of us (to my knowledge) work for BA, and none of us speak for anyone other then ourselves. I try to refrain from comment on the principal that there are MANY potential factors. The Wing commander of my CAP Wing crashed into Mt Potosi in November and I have not made any speculation because there are MANY possible causes. In this case, however, I feel that there is minimal potential for numerous causes and all the evidence so far does really only point to one logical cause, that of fuel contamination.
Watching that liveleak video, that is WAY nose high. I'm sure angle has something to do with it, but it looks to me like the APU tailpipe may actually be below the MLG. That's obscenely nose high!
Cobra, that picture is HILARIOUS!
Watching that liveleak video, that is WAY nose high. I'm sure angle has something to do with it, but it looks to me like the APU tailpipe may actually be below the MLG. That's obscenely nose high!
Cobra, that picture is HILARIOUS!
