NTSB update on Asiana 214
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joema - interesting, but which language is that transcribed from??? I had great trouble understanding what the supposed 'logic' was - in Asiana's case there was only 1 'system' in use - A/T and NO aircraft 'system' controlling speed.
porter -"don't try to stipulate there is no valid reason..." - not sure where you saw that 'stipulation'?? I have not and I am asking HERE. I agree with the futility of the search for answers here, however - I have not had one 777 pilot 'justify' this mode.
It is apparent that there is resistance amongst many, including non-aviators, in incorporating protection to aircraft in a world of significantly diminishing pilot ability. That spells one thing to me and it is not pretty.
porter -"don't try to stipulate there is no valid reason..." - not sure where you saw that 'stipulation'?? I have not and I am asking HERE. I agree with the futility of the search for answers here, however - I have not had one 777 pilot 'justify' this mode.
It is apparent that there is resistance amongst many, including non-aviators, in incorporating protection to aircraft in a world of significantly diminishing pilot ability. That spells one thing to me and it is not pretty.
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I have not had one 777 pilot 'justify' this mode
Last edited by porterhouse; 24th Jun 2014 at 22:57.
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there is resistance amongst many, including non-aviators, in incorporating protection to aircraft in a world of significantly diminishing pilot ability
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@BOAC If you ever do find the design rationale for not including airspeed protection in FLCH mode, please do post it. I've searched in vain. At first I thought I was overlooking something basic but the more I searched the more it seemed to be the product of maintaining an internally coherent design philosophy that most pilots aren't really conscious of. Which I doubt is a complete answer.
@those who think it would be dangerous to include airspeed protection in FLCH mode, please explain how this would be so, particularly in light of the fact that some form of speed protection is included in every other mode. See also airbus (no need to start a B v. A war though; I'm not saying A is better; just that airspeed protection whenever the A/T is on is possible).
@those making the argument that B didn't take away the protection in FLCH mode because it was never there, that's a semantic point--it doesn't answer the question. If you prefer the question be rephrased as "why was airspeed protection given in every other mode but not FLCH mode," so be it.
@those who think it doesn't matter if you have airspeed protection or not because you're suppose to watch your airspeed, that's a point about culpability, not an answer to the question.
All-caps disclaimer: I'M NOT TRYING TO ABSOLVE THE PILOTS AND I'M NOT TRYING TO BLAME BOEING.
Rather, like BOAC, I am genuinely curious as to the design rationale behind no airspeed protection in FLCH mode.
@those who think it would be dangerous to include airspeed protection in FLCH mode, please explain how this would be so, particularly in light of the fact that some form of speed protection is included in every other mode. See also airbus (no need to start a B v. A war though; I'm not saying A is better; just that airspeed protection whenever the A/T is on is possible).
@those making the argument that B didn't take away the protection in FLCH mode because it was never there, that's a semantic point--it doesn't answer the question. If you prefer the question be rephrased as "why was airspeed protection given in every other mode but not FLCH mode," so be it.
@those who think it doesn't matter if you have airspeed protection or not because you're suppose to watch your airspeed, that's a point about culpability, not an answer to the question.
All-caps disclaimer: I'M NOT TRYING TO ABSOLVE THE PILOTS AND I'M NOT TRYING TO BLAME BOEING.
Rather, like BOAC, I am genuinely curious as to the design rationale behind no airspeed protection in FLCH mode.
Last edited by sflaperons; 24th Jun 2014 at 23:05. Reason: typo
Rather, like BOAC, I am genuinely curious as to the design rationale behind no airspeed protection in FLCH mode.
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By the way, none such protection are available to us lowly GA pilots, we must know "how to fly", we can't hide behind "Cessna why didn't you help us", but I guess if you are 10,000 hrs captain all of a sudden someone must help you wipe your nose, you forgot how to do it.
Defending the indefensible. Put in Min Speed Protection, you lot. Or remove ABS, seatbelts, traction control, and anything else man invented to save himself if he gets out of his depth (for whatever reason) with technology! 
Ever heard of an AFS Override switch?
Originally Posted by TDRacer
Are you really advocating an A/T that can unilaterally apply thrust, even when the pilot has commanded it not to? What if there was an issue with unreliable airspeed (been known to happen), do you want the A/T to firewall the throttles against the pilots wishes to maintain the erroneous airspeed during landing?
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Kindly educate someone who's been out of the loop a while:
I think we all have a basic picture of the 777 a/t "hold" logic now, and maybe even Boeing's rationale for it. But paint me a picture, please, of how this logic compares to other Boeing products - 748, 767, 737NG, maybe 737MAX if anyone is in the know.
Offhand, I'd think Boeing would make them as similar as possible, for a number of reasons.
I think we all have a basic picture of the 777 a/t "hold" logic now, and maybe even Boeing's rationale for it. But paint me a picture, please, of how this logic compares to other Boeing products - 748, 767, 737NG, maybe 737MAX if anyone is in the know.
Offhand, I'd think Boeing would make them as similar as possible, for a number of reasons.
Offhand, I'd think Boeing would make them as similar as possible, for a number of reasons.
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All the crew except the Jump seat guy were asleep here guys. Bad tradesman always blame their tools not their technique or system knowledge. The Captain under training was coming off an A320 where the Thrust levers don't move when Auto Thrust is engaged. Opposite to Boeing. I wonder if that played a factor aswell. If we are considering all factors.
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. The Captain under training was coming off an A320
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For the record, I'm posting this as an ex-FA with zero experience of flying an aircraft and just enough knowledge to be a nuisance. Caveats over, here we go...
I guess that what I'm saying is this - On a perfect day, four pilots watched the aircraft fly itself into the ground: I can't think of any circumstances under which this is acceptable, or for which they should be regarded as blameless. I cut my teeth working down the back on Boeing charters around the med, where our pilots routinely flew visual approaches with few navaids into such delights as Funchal, Samos, Mykonos and Gibraltar. I would like to go and the record and acknowledge a level of skill and professionalism involved that so far exceeds that visible in SFO that it is barely recognisable as the same industry.
I apologise for sounding cross: I think we have a right to expect better, much better and blaming the equipment just doesn't cut it!
- The aircraft started above the appropriate glide path and never actually seems to have been on it, despite indications from PAPI's and what one might (optimistically, it turns out) expect from somebody on the flight deck monitoring the profile.
- Flaps 30 was called for at a time when the aircraft speed was in excess of that appropriate for this setting.
- Autopilot settings were inappropriate and not fully understood by the crew.
- Despite all those wise heads in the cockpit, apparently nobody was monitoring airspeed or altitude.
- The weather conditions were perfect.
I guess that what I'm saying is this - On a perfect day, four pilots watched the aircraft fly itself into the ground: I can't think of any circumstances under which this is acceptable, or for which they should be regarded as blameless. I cut my teeth working down the back on Boeing charters around the med, where our pilots routinely flew visual approaches with few navaids into such delights as Funchal, Samos, Mykonos and Gibraltar. I would like to go and the record and acknowledge a level of skill and professionalism involved that so far exceeds that visible in SFO that it is barely recognisable as the same industry.
I apologise for sounding cross: I think we have a right to expect better, much better and blaming the equipment just doesn't cut it!
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Thank you sflaperons and C Bloggs - maybe we can get some sensible answers in this morass.
swh - I sincerely hope you are never involved in design, certification or operation of aircraft.
Please - we do NOT need to still be discussing the 'competency' of this crew. That is obvious. We do not need to be discussing the wiping of 10,000 hr Captain's noses either - it seems that designers and certificators believe they should be wiped. The question is why is the msr protection NOT there in one mode when it is there in others. I understand the current thinking on SOPs for these a/c is that A/T is to be used at all times. In that case it needs to work properly and to me, if I HAVE to use it, having HAL go to 'HOLD' with no msr when I close the throttles is not 'properly' - nor necessary.
This is NOT an attempt to pass any blame to manufacturers - the 'guilty parties' are obvious. If there is no good reason for the feature (and I have not seen one) it will be simple to correct it.
swh - I sincerely hope you are never involved in design, certification or operation of aircraft.
Please - we do NOT need to still be discussing the 'competency' of this crew. That is obvious. We do not need to be discussing the wiping of 10,000 hr Captain's noses either - it seems that designers and certificators believe they should be wiped. The question is why is the msr protection NOT there in one mode when it is there in others. I understand the current thinking on SOPs for these a/c is that A/T is to be used at all times. In that case it needs to work properly and to me, if I HAVE to use it, having HAL go to 'HOLD' with no msr when I close the throttles is not 'properly' - nor necessary.
This is NOT an attempt to pass any blame to manufacturers - the 'guilty parties' are obvious. If there is no good reason for the feature (and I have not seen one) it will be simple to correct it.
My understanding is that the pilot flying was a highly experienced instructor transitioning from the Airbus A320 (with its different philosophies) to the 777. He was still flying with a training captain in the right hand seat, so probably less than half way through his line training.
Trainees (even experienced ones) make mistakes and he pretty thoroughly messed up the approach. The instructor in the right hand seat was on his first solo flight in that role in the aircraft. The instructors amongst us will know that there is a fine line in when to step in. He pointed out that they were high, but does not seem to have been providing height to distance information e.g x miles x feet above path. Where he comprehensively failed was in not calling for a go-around when the approach became obviously unstable.
Arguably this point was reached earlier. But by a thousand feet the aircraft was clearly not stabilised and latest then they should have gone around. Skybrary has interesting information about people pressing on with unstabilised approaches. In my opinion it continues to be one of the most frequent breaches of standard operating procedure.
The discussions about lack of manual flying skills and minimum speed protection are valid. But in this case an equally important conclusion is that even instructors do not seem to be go around enough minded. Particularly in line training we should be emphasising the need to for a missed approach if you are not stable.
Trainees (even experienced ones) make mistakes and he pretty thoroughly messed up the approach. The instructor in the right hand seat was on his first solo flight in that role in the aircraft. The instructors amongst us will know that there is a fine line in when to step in. He pointed out that they were high, but does not seem to have been providing height to distance information e.g x miles x feet above path. Where he comprehensively failed was in not calling for a go-around when the approach became obviously unstable.
Arguably this point was reached earlier. But by a thousand feet the aircraft was clearly not stabilised and latest then they should have gone around. Skybrary has interesting information about people pressing on with unstabilised approaches. In my opinion it continues to be one of the most frequent breaches of standard operating procedure.
The discussions about lack of manual flying skills and minimum speed protection are valid. But in this case an equally important conclusion is that even instructors do not seem to be go around enough minded. Particularly in line training we should be emphasising the need to for a missed approach if you are not stable.
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Originally Posted by BOAC
joema - interesting, but which language is that transcribed from??? I had great trouble understanding what the supposed 'logic' was - in Asiana's case there was only 1 'system' in use - A/T and NO aircraft 'system' controlling speed.
(NTSB): Did Boeing consider putting on an automatic autothrottle activation at a minimum speed, regardless of the status of the modes?
(John Cashman, former Boeing chief test pilot during 777 development): We certainly always look at possibilities. The main problem with that goes back to that original philosophy -- not changing modes and autopilot that the pilot does not command. What would happen if you just activated the throttle is you would have two controllers of one parameter. The autopilot would be controlling speed by pitching, and the autothrottle would be controlling speed by changing thrust. It does not work very well, so you have to make a mode change, put the autopilot in a different control mode, and/or the thrust. It is difficult to do, and it was violating one of our fundamental find concepts.
(NTSB): Captain Cashman, you talk about autothrottle wake up. Isn't the issue of autothrottle for protection?
(Cashman): The envelope protection of the auto engage or wake-up function is an element of the stall protection, but it is not the stall protection system. In other words, it is related to operation when the autothrottle is turned off or has been disengaged inadvertently or a failure to drop it off, that it will engage itself. It is not a function that if the autothrottle is already in another mode, it will change the mode and do something to control speed. It was really there to come alive and engage itself when it had been selected off.
(NTSB): Captain Cashman, why no auto thrust protection in flight level change mode?
(Cashman): The autothrottle protection feature or wake-up feature is only when the autothrottle is turned off. In a flight level change mode, the speed is being controlled by pitching the airplane, not by moving the throttle.
(NTSB): Given that, the situation when the flight level changes and the autothrottle is on hold, do you consider that to be an error-tolerant design?
(Bob Myers, Boeing Chief of Flight Deck Engineering): If we get a wake-up or a mode transition of the autothrottle for a low-speed condition, say, we had to transition the pilots authorizing that command mode change. They would have had two systems controlling speed. We had to rectify that situation. In that case, we would end up with two mode changes and a thrust increase, and if this low-speed condition came about because of an engine problem, we might also be pushing thrust up into the asymmetric thrust conditions. We would have potentially two mode changes uncommitted by the pilot, a thrust increase, possibly asymmetric thrust increase, and we would be violating our philosophy of the pilot having authority. We thought the less confusing of the situations was the design we chose.
"What is the design rationale for an emergency brake on a car that you can't pump" would seem to me a similar question.
I accept that I may misunderstand the system feature.
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Jo - thanks for the work on that transcript. I still do not understand Boeing's 'reservations' on multi-modes, since all we are looking at in the Asiana case is manual flight with A/T. One thing puzzles me in it - it appears that Boeing designed it to work with A/T off and talk of it 'engaging' in that condition - not what I would want having selected it off! At least the 73 msr function was inactive with A/T off.
LW_50 - Indeed not - it is, I think, simply designed to allow altitude change, but we know the crew was well confused with modes etc. as shown by the selection of it with a higher altitude selected BUT I still argue that msr would be a good idea whatever it is being used for.
LW_50 - Indeed not - it is, I think, simply designed to allow altitude change, but we know the crew was well confused with modes etc. as shown by the selection of it with a higher altitude selected BUT I still argue that msr would be a good idea whatever it is being used for.
Originally Posted by Capt Cashman
If we get a wake-up or a mode transition of the autothrottle for a low-speed condition, say, we had to transition the pilots authorizing that command mode change. They would have had two systems controlling speed. We had to rectify that situation. In that case, we would end up with two mode changes and a thrust increase, and if this low-speed condition came about because of an engine problem, we might also be pushing thrust up into the asymmetric thrust conditions. We would have potentially two mode changes uncommitted by the pilot, a thrust increase, possibly asymmetric thrust increase, and we would be violating our philosophy of the pilot having authority. We thought the less confusing of the situations was the design we chose.