Asiana flight crash at San Francisco
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>> Autothrust
Please can a 777 driver explain the A/T. Only 777 please.
Why if the A/T is engaged would the speed decay below target speed. On the Bus with FD off the the AT will follow the speed bug. On Thrust Idle open des the throttles remain at idle.
Which mode would allow the AT to go below target speed.
AT is usually always engaged.
<<
Wow... just had a mini epiphany. It would be great for a 777 pilot to chime in on the following thought...
The 757/767 auto-throttles go into THR HLD and won't "wake up" till they capture the GS when APP is armed (as I recall... don't have the systems manual handy at the moment.) If the ILS is out of service and the pilot does not select SPD on the A/T panel, the thrust levers will remain in HLD waiting for the "capture". Perhaps this small bit of automation confusion led the Asiana pilots to falsely believe the speed would be protected when in fact the thrust levers will remain at idle (waiting for the capture.) I'm wondering if the 777 has a similar auto-throttle logic?
Where I've seen this occur most is a manual descent where the pilot flying shallows his rate of descent to 100-200 VVI and airspeed decays below target because ALT CAP has not occurred (till approximately 20-50 feet above level off.) I always warn new pilots (to the fleet) to remain vigilant whenever they see THR HLD, and always mentally confirm a capture and wake up of the auto-throttles.
Just thinking out loud why the airspeed decayed so significantly (according to an initial NTSB briefing.)
Please can a 777 driver explain the A/T. Only 777 please.
Why if the A/T is engaged would the speed decay below target speed. On the Bus with FD off the the AT will follow the speed bug. On Thrust Idle open des the throttles remain at idle.
Which mode would allow the AT to go below target speed.
AT is usually always engaged.
<<
Wow... just had a mini epiphany. It would be great for a 777 pilot to chime in on the following thought...
The 757/767 auto-throttles go into THR HLD and won't "wake up" till they capture the GS when APP is armed (as I recall... don't have the systems manual handy at the moment.) If the ILS is out of service and the pilot does not select SPD on the A/T panel, the thrust levers will remain in HLD waiting for the "capture". Perhaps this small bit of automation confusion led the Asiana pilots to falsely believe the speed would be protected when in fact the thrust levers will remain at idle (waiting for the capture.) I'm wondering if the 777 has a similar auto-throttle logic?
Where I've seen this occur most is a manual descent where the pilot flying shallows his rate of descent to 100-200 VVI and airspeed decays below target because ALT CAP has not occurred (till approximately 20-50 feet above level off.) I always warn new pilots (to the fleet) to remain vigilant whenever they see THR HLD, and always mentally confirm a capture and wake up of the auto-throttles.
Just thinking out loud why the airspeed decayed so significantly (according to an initial NTSB briefing.)
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ELAC post 651:
... some pilots just stop actively thinking and doing and become passive observers in the face of a problem they don't know how to control.
Q: Deer in the headlights?
... some pilots just stop actively thinking and doing and become passive observers in the face of a problem they don't know how to control.
Q: Deer in the headlights?
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Most of you are all so perfect
BenThere you say it well!
Quote: One thing occurs to me, that I can sit and pass judgment, aged 62 and never had an incident or violation, but who knows what will happen on the next flight?
When I'm retired and safely out of the arena I'll pass judgment mercilessly, I'm sure. Until then, I'm glad it wasn't me, I acknowledge I haven't always been perfect, and on an occasion or two I've been lucky. And I've been covered more than once by the other guy in the cockpit.
I've got some sympathy for the Korean crew going through this ordeal. The pilot flying, I think, is responsible, and to a lesser extent, the pilot not flying. They both have hell to pay, as they should. That's how the system works. But haven't we all screwed up from time to time, but just had the luck, common sense, or help to recover in time, before it became an incident?
I've been flying for 10 years and the majority of it in Papua New Guinea, I have many years of flying to go, at 35 I hope 30 at least. I haven't yet scratched anything and as time goes by and I gain more experience I feel I get better at what I do but I have had 1 or 2 close calls in the early years, I'm not perfect! I now know why I so rarely visit this site, many posters are infuriating with their narcissistic views of themselves. Yes this is a major screw up if initial reports are accurate but does that really make you (you know who you are) the worlds greatest aviators able to pass judgement on all others?
Quote: One thing occurs to me, that I can sit and pass judgment, aged 62 and never had an incident or violation, but who knows what will happen on the next flight?
When I'm retired and safely out of the arena I'll pass judgment mercilessly, I'm sure. Until then, I'm glad it wasn't me, I acknowledge I haven't always been perfect, and on an occasion or two I've been lucky. And I've been covered more than once by the other guy in the cockpit.
I've got some sympathy for the Korean crew going through this ordeal. The pilot flying, I think, is responsible, and to a lesser extent, the pilot not flying. They both have hell to pay, as they should. That's how the system works. But haven't we all screwed up from time to time, but just had the luck, common sense, or help to recover in time, before it became an incident?
I've been flying for 10 years and the majority of it in Papua New Guinea, I have many years of flying to go, at 35 I hope 30 at least. I haven't yet scratched anything and as time goes by and I gain more experience I feel I get better at what I do but I have had 1 or 2 close calls in the early years, I'm not perfect! I now know why I so rarely visit this site, many posters are infuriating with their narcissistic views of themselves. Yes this is a major screw up if initial reports are accurate but does that really make you (you know who you are) the worlds greatest aviators able to pass judgement on all others?
Summary of NTSB preliminary information.
"High points" of FDR from NTSB press conference.
Note NTSB said they need to validate some data, such as aircraft speed.
From cockpit voice recorder.
2 hours of voice recording.
24 hours of recorded data, 1400 parameters captured entire flight
Other
Tower controller didn't see anything wrong with approach until it hit the wall.
No reports of adverse weather.
PAPI lights were operational but damaged in crash so NOTAMed post crash.
1100 777s delivered.
169 with Pratt and Whitney
700 GE
223 with RR
Runway was 11380 in length.
Localiser was in operation
Glideslope was out of service and NOTAMed as such.
9 fire and rescue vehicles
NTSB looking at crew, cockpit and instrument configuration, passenger response, CRM, fire service response, passenger injury vis a v seat location relationship.
No similarities seen so far between this and LHR accident.
Investigators will be on scene for a week.
Too early to rule anything out as the cause.
This information are the facts and should not be reported or by media as an indication of NTSBs view of cause of accident.
Note NTSB said they need to validate some data, such as aircraft speed.
From cockpit voice recorder.
2 hours of voice recording.
Aircraft configured for approach, flaps 30, gear down and target speed called for 137 knots.
A call to increase speed 7 seconds before impact
Sound of stick shaker heard 4 seconds prior to impact
"Go around" called 1.5 seconds before impact
No discussion of aircraft anomalies by crew
From Flight data recorder24 hours of recorded data, 1400 parameters captured entire flight
Throttles set at idle and airspeed slowed below target airspeed to "significantly below 137 knots we are not talking a few knots"
Throttles advanced a few seconds before impact and engines appear to respond normally.
Other
Tower controller didn't see anything wrong with approach until it hit the wall.
No reports of adverse weather.
PAPI lights were operational but damaged in crash so NOTAMed post crash.
1100 777s delivered.
169 with Pratt and Whitney
700 GE
223 with RR
Runway was 11380 in length.
Localiser was in operation
Glideslope was out of service and NOTAMed as such.
9 fire and rescue vehicles
NTSB looking at crew, cockpit and instrument configuration, passenger response, CRM, fire service response, passenger injury vis a v seat location relationship.
No similarities seen so far between this and LHR accident.
Investigators will be on scene for a week.
Too early to rule anything out as the cause.
This information are the facts and should not be reported or by media as an indication of NTSBs view of cause of accident.
Last edited by mickjoebill; 8th Jul 2013 at 01:40.
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I read that Lion has an SOP to disengage the auto throttles when the autopilot is disconnected and am wondering is that the SOP for the Korean carriers? Why would the auto throttles not have been engaged? Many years of flying 74s and MD-11s always using the ATs even for visuals unless it is super gusty. I don't understand how you can let an airliner get that slow on an approach...
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RE HITTING WATER WITH TAIL PER VIDEO
I am not a pilot- and do not play one on TV. But I am a retired BA engineer who worked on 777 until shortly after first flight
Looking at the cnn video - and living in seattle area, the white cloud just before the hit looks more like a hydroplane roostertail of the good ole days. (** addition - IF the 777 had a tail skid that dropped with the gear, it would make a great roostertail ** )
IMHO that would explain the nose high- landing gear hitting on ground just after tail hits water, and the section aft of the pressure bulkhead being torn off by the seawall/rocks- along with some reports of debris in the water.
One photo of the landing gear shows the main landing gear beam still attached- further supporting gear slightly higher than seawall at time of impact of tail section.
I note that the break of the upper fuselage aft section on top does not appear to be at the normal production join of the aft pressure bulkhead, ((** correction most of the break of the tail cone/rudder DID occur at the production joint- and the junction of the rudder/vertical stabilizer and the fuselage may account for the tear **) to fuselage but a tear extending a few feet forward of the join between fuselage and the bulkead. The vertical split in the " middle " of the bulkhead ***may** indicate some significant sideways impact with the plane crabbing to the left.
All told, the impact loads well above ' hard landings" with most " all ?? " of the floor intact is but one indication of the amazing structural integrity of the 777 floor.
I'm sure there will be many lessons learned as to failure modes of structure.
Looking at the cnn video - and living in seattle area, the white cloud just before the hit looks more like a hydroplane roostertail of the good ole days. (** addition - IF the 777 had a tail skid that dropped with the gear, it would make a great roostertail ** )
IMHO that would explain the nose high- landing gear hitting on ground just after tail hits water, and the section aft of the pressure bulkhead being torn off by the seawall/rocks- along with some reports of debris in the water.
One photo of the landing gear shows the main landing gear beam still attached- further supporting gear slightly higher than seawall at time of impact of tail section.
I note that the break of the upper fuselage aft section on top does not appear to be at the normal production join of the aft pressure bulkhead, ((** correction most of the break of the tail cone/rudder DID occur at the production joint- and the junction of the rudder/vertical stabilizer and the fuselage may account for the tear **) to fuselage but a tear extending a few feet forward of the join between fuselage and the bulkead. The vertical split in the " middle " of the bulkhead ***may** indicate some significant sideways impact with the plane crabbing to the left.
All told, the impact loads well above ' hard landings" with most " all ?? " of the floor intact is but one indication of the amazing structural integrity of the 777 floor.
I'm sure there will be many lessons learned as to failure modes of structure.
Last edited by DWS; 8th Jul 2013 at 03:27. Reason: minor correction on bulkhead issue
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Suggest you re read Barit1 and Won2Go recent posts..very erudite and appropriate . As a long time ex bus driver and a recent convert to the 777, FLCH appears to be a real design trap that really after all this time, particularly with the ER models, should have been redisigned out of the auto system..I believe the 787 has something very similar to managed descent and open descent but in any event, a bus would have reverted to an alpha floor mode which may have salvaged the hull and pax, even at the later stage of GA application in this event.
Korean cultural dynamics MUST be scrutinised again and the whole issue of standardising, possibly via ICAO, the stabilised approach criteria, now has to be mandated. Asian carriers with large a/c do not fly visual approaches..the number 3 and 4 options never apply..it is always with an attempt to primarily 1L the RX and chinese G/s the approach via the FMS. Situational awareness is always via the "rose nav" and distance out, never by looking out of the obvious window. Traffic is always courtesy of TCAS and rarely through lookout. Min qualification Asian training is now the norm and type conversions are the thinnest courses that the bean counters sanction for the techs to design. Equally, minimum line training after minimum sims are also the norm. If the FO was handling Pilot, with 43 hours on type, i.e. less than 4 long haul sectors, it will be interesting to see what training experience the captain possessed.
SFO, particularly with arrivals from the west, is frequently a slam dunk approach with a visual over or close to the san Mateo Bridge. PAPI options are sometimes limited and in trail approaches with other aircraft close in parallel on the L or R runway, pretty much the norm. For those of us who employ old school skills and actually fly the a/c manually and visually, this is a straight forward exercise..to others, irrespective of where the cheese may be..its a challenge. I am drawn to reflect on what appears to be a cliche nowadays.."if you think training is expensive..try an accident"....
Korean cultural dynamics MUST be scrutinised again and the whole issue of standardising, possibly via ICAO, the stabilised approach criteria, now has to be mandated. Asian carriers with large a/c do not fly visual approaches..the number 3 and 4 options never apply..it is always with an attempt to primarily 1L the RX and chinese G/s the approach via the FMS. Situational awareness is always via the "rose nav" and distance out, never by looking out of the obvious window. Traffic is always courtesy of TCAS and rarely through lookout. Min qualification Asian training is now the norm and type conversions are the thinnest courses that the bean counters sanction for the techs to design. Equally, minimum line training after minimum sims are also the norm. If the FO was handling Pilot, with 43 hours on type, i.e. less than 4 long haul sectors, it will be interesting to see what training experience the captain possessed.
SFO, particularly with arrivals from the west, is frequently a slam dunk approach with a visual over or close to the san Mateo Bridge. PAPI options are sometimes limited and in trail approaches with other aircraft close in parallel on the L or R runway, pretty much the norm. For those of us who employ old school skills and actually fly the a/c manually and visually, this is a straight forward exercise..to others, irrespective of where the cheese may be..its a challenge. I am drawn to reflect on what appears to be a cliche nowadays.."if you think training is expensive..try an accident"....
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Lessons in error prevention from aviation - good and bad
I'm an emergency physician. I'm not a pilot.
Over the past several years in my profession, we have been looking to aviation for lessons about error prevention. This has been enormously valuable for us; we practice more safely now because of the things we have learned from pilots and other aviation professionals.
That's the good.
Although we in emergency medicine (and medicine generally) owe a great debt to pilots for their leadership in understanding how to make things safer, we have in my experience avoided - entirely - the racism that riddles this thread.
Yes, I know it's just a few posters, but I can't ever recall any post-mortem discussions of physician error - on anonymous online fora or otherwise - that explicitly cited the race or national origin of the doctor who screwed up as a contributing factor for the screw-up. Training systems, yes; amount of experience, yes; even "culture" in a practice environment, yes; but *race* of the doctor? Never.
If there really are a significant number of pilots who seriously think that Korean pilots as Koreans were more likely to make the errors it appears these pilots made, that's profoundly disappointing.
Over the past several years in my profession, we have been looking to aviation for lessons about error prevention. This has been enormously valuable for us; we practice more safely now because of the things we have learned from pilots and other aviation professionals.
That's the good.
Although we in emergency medicine (and medicine generally) owe a great debt to pilots for their leadership in understanding how to make things safer, we have in my experience avoided - entirely - the racism that riddles this thread.
Yes, I know it's just a few posters, but I can't ever recall any post-mortem discussions of physician error - on anonymous online fora or otherwise - that explicitly cited the race or national origin of the doctor who screwed up as a contributing factor for the screw-up. Training systems, yes; amount of experience, yes; even "culture" in a practice environment, yes; but *race* of the doctor? Never.
If there really are a significant number of pilots who seriously think that Korean pilots as Koreans were more likely to make the errors it appears these pilots made, that's profoundly disappointing.
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Having just watched the video footage of the accident, I can now understand how witnesses described the aircraft cartwheeling and am thoroughly astounded that there were not significantly more casualties. It is enormous testament to the quality of design that the fuselage stayed relatively intact following that sequence. The footage actually looks very similar to the crash sequence/progression at Sioux City, (obviously a far lower speed less inertia and different attitude at first impact) With regards to cause, I do not wish to, nor am I qualified to speculate, the NTSB will, in their own time provide us with a full sequence of events that led to a broken aircraft and sadly lives lost.
Good point pucka,
I'm fresh off 737 classic onto the Bus and visual approaches were flown AP/FD off, A/thrust off.
The bus is flown AP/FD off bird on but speed is still managed.
If this poor dude came off the bus he might have resorted to the 'Bus managed speed' mentality and neglected speed management which could have been manual thrust. Wouldn't excuse not monitoring the basics of flying.
In any case very sad for all involved.
I'm fresh off 737 classic onto the Bus and visual approaches were flown AP/FD off, A/thrust off.
The bus is flown AP/FD off bird on but speed is still managed.
If this poor dude came off the bus he might have resorted to the 'Bus managed speed' mentality and neglected speed management which could have been manual thrust. Wouldn't excuse not monitoring the basics of flying.
In any case very sad for all involved.
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It's pretty obvious at this point that there's nowhere near enough publicly available data to support a "why" analysis, even if the "how" seems fairly clear. That said, I think we should all be careful when comparing other accidents to this one.
That's not what happened. The "speed ref" switch was (incorrectly) left in a position appropriate for icing conditions when there were none - thus the Stall Warning was triggered well before the aircraft was actually approaching stall. The crew response to the warning was inappropriate and resulted in a crash, but the real devil in the detail there was that both pilots were considerably more fatigued in real terms than they would have appeared on paper, and on top of that the F/O was evidently sick.
Company policy at the time was clearly coercive in terms of putting crew in the flight deck who were clearly at risk of impaired ability and expecting them to, for want of a better phrase, "suck it up, dig deep and be glad you have a job".
Given that, us westerners might want to do a little soul-searching regarding our own business culture before making judgement calls on others. In aviation, poor decision-making and culture outside the flight deck can be just as dangerous as inside, if not more so!
Again, fatigue was considered a possible factor there - at least by some. That devil is lurking in the details again - namely that the Guam equipment was still broadcasting a partial signal on the ILS frequency, and the result was a false glideslope capture - which was at odds with the NOTAM. The crew did not clarify the situation with ATC, which was undoubtedly a mistake (though like Colgan forgetting to set "speed ref" properly, very much the kind of mistake that fatigue can make more likely). The last oversight was the assumption that the DME equipment was at the runway threshold when it was in fact offset some distance ahead.
One of the things I've noticed about the posts on Korean crew and airlines is that a lot of them indicate that their experience was some time ago. I can't speak of Asiana, but I do know that after KAL afflicted themselves with a woeful safety record about a decade ago they were supposed to have completely overhauled their crew training, operations and company culture. Their record has since shown a dramatic improvement as far as I know, and it'd be interesting to hear from those with experience in, say, the last 5 years.
Interesting - but two things occur to me. The AAIB spent an inordinate amount of time and effort trying to replicate the problem, and that was the only scenario that came close to doing so. Secondly, I don't know a great deal about fluid dynamics as they apply to water and kerosene - but unless you were to build a test rig that simulated the 777's fuel tanks at full size (do they even have a building large enough to do that?), then those that do know would probably have to adjust the water:fuel ratio accordingly given the smaller volume of the test rig's tank.
It's usually the nature of experiments that it's enough to demonstrate the principle of the hypothesis when it's not possible or practical to mimic the conditions precisely - especially when there are so many variables involved. This goes all the way back to when RAE Farnborough built the giant water tank to test a Comet 1 airframe to destruction (though it should be noted that it was the other team working on the wreckage reconstruction that determined the failure point and break-up sequence first).
Company policy at the time was clearly coercive in terms of putting crew in the flight deck who were clearly at risk of impaired ability and expecting them to, for want of a better phrase, "suck it up, dig deep and be glad you have a job".
Given that, us westerners might want to do a little soul-searching regarding our own business culture before making judgement calls on others. In aviation, poor decision-making and culture outside the flight deck can be just as dangerous as inside, if not more so!
Again, fatigue was considered a possible factor there - at least by some. That devil is lurking in the details again - namely that the Guam equipment was still broadcasting a partial signal on the ILS frequency, and the result was a false glideslope capture - which was at odds with the NOTAM. The crew did not clarify the situation with ATC, which was undoubtedly a mistake (though like Colgan forgetting to set "speed ref" properly, very much the kind of mistake that fatigue can make more likely). The last oversight was the assumption that the DME equipment was at the runway threshold when it was in fact offset some distance ahead.
One of the things I've noticed about the posts on Korean crew and airlines is that a lot of them indicate that their experience was some time ago. I can't speak of Asiana, but I do know that after KAL afflicted themselves with a woeful safety record about a decade ago they were supposed to have completely overhauled their crew training, operations and company culture. Their record has since shown a dramatic improvement as far as I know, and it'd be interesting to hear from those with experience in, say, the last 5 years.
It's usually the nature of experiments that it's enough to demonstrate the principle of the hypothesis when it's not possible or practical to mimic the conditions precisely - especially when there are so many variables involved. This goes all the way back to when RAE Farnborough built the giant water tank to test a Comet 1 airframe to destruction (though it should be noted that it was the other team working on the wreckage reconstruction that determined the failure point and break-up sequence first).
Last edited by DozyWannabe; 8th Jul 2013 at 02:55.
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Pilot Lee Kang-kook's maiden flight to SFO in 777
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Mr. Palmtree,
AFAIK, Boeing recommends that the auto throttles be disengaged while hand flying an approach.
At this level of ones career, we must be able to perform basic functions of flying. That includes a scan, interpretation of said indications and acting accordingly. If you can't maintain airspeed during a daylight straight-in visual approach, I would suggest that you need more training, or may want to wait a while until you master such basic skills. If you're that inexperienced, you should not be flying 290+ people in a wide body.
AFAIK, Boeing recommends that the auto throttles be disengaged while hand flying an approach.
At this level of ones career, we must be able to perform basic functions of flying. That includes a scan, interpretation of said indications and acting accordingly. If you can't maintain airspeed during a daylight straight-in visual approach, I would suggest that you need more training, or may want to wait a while until you master such basic skills. If you're that inexperienced, you should not be flying 290+ people in a wide body.
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Seeing that crash video ... wow. The performance of the Boeing airframe was simply unbelievable. That alone may have saved 100s of lives.
Every Boeing employee should take pride in that.
Every Boeing employee should take pride in that.
Last edited by ensco; 8th Jul 2013 at 02:52.
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Post444 is also very apt now we know the FO was still under training on type. Was it a 2 sector day for these guys too possibly? Complacency via fatigue? Only in seat rest? Automation reliance issues..AGAIN?
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it states on Cnn that the co pilot was flying the airplane from the left seat at the time of the crash ...
I have never flown in asia but i guess it is normal for whoever is flying the airplane to occupy the left hand seat ?
I have never flown in asia but i guess it is normal for whoever is flying the airplane to occupy the left hand seat ?