Asiana flight crash at San Francisco
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I don't know the 777 but in the 737/757/747 manual flying an approach with the A/T on worked well for me. It took a little while to get used to the effect on pitch, but I always held on to the throttles so I got advanced notice of the changes as the throttles moved before the actual thrust changed.
I was very easy and not confusing at all.
Very comforting in fact, knowing that the airplane was responding to the changes and maintaining the selected speed to a very close tolerance..
What was the benefit? It gave me very good speed control, especially in gusty conditions, and allowed me to use Vref+5 as the target speed vice Vref +5 +gusts. Especially on short runways it was a bonus.
Not of much use in calm conditions, so I did not use it all the time and some airlines I worked with banned it as a practice although I don't remember if Boeing did allow it.
I was very easy and not confusing at all.
Very comforting in fact, knowing that the airplane was responding to the changes and maintaining the selected speed to a very close tolerance..
What was the benefit? It gave me very good speed control, especially in gusty conditions, and allowed me to use Vref+5 as the target speed vice Vref +5 +gusts. Especially on short runways it was a bonus.
Not of much use in calm conditions, so I did not use it all the time and some airlines I worked with banned it as a practice although I don't remember if Boeing did allow it.
So, you're saying that being lined up on final 14 mile out, on a 3 degree glide, and slow enough to a) throw out the gear, and b) start throwing out flaps, is a "challenge"?
I'm not saying this was the cause of the accident, simply that it COULD have been a contributing factor. It's fairly obvious they should have been monitoring the speed and thrust more closely, and gone around much earlier in the approach when it was obvious they were unstable. I guess we'll have to wait for the NTSB report to find out why that didn't happen.
Last edited by BuzzBox; 16th Jul 2013 at 03:51.
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180 to 5
phil gollin
[QUOTE]There is a majority (but not universal) feeling that the ATC advisory "180 kts to 5nm"/4-degree approach was a possible contributory factor./QUOTE]
I'm not sure where you get the 4-degree approach thing from..... that wasn't in the instructions they were given and wouldn't be a normal thing anyway.
But I believe the 180 to 5 miles instruction might have contributed to an unstable approach, but it was not insurmountable. Ms. Hersman indicated that the speed limit for a 777 to select full flap was 160 kts. If you comply with the 180 till 5 instruction then you are accepting that you will not be in the landing configuration until quite late. In other words, you fly to 5 miles at 180 kts, then slow to below 160, then select full flap, then slow to target speed (in this case 137 kts). Only then, with the engines spooled up, and maintaining a stable target speed, on a stable glidepath to the touchdown zone with a rate of descent less than 1000fpm, can you consider the approach to be stabilized....my words are approximate, each company's SOPs will be very specific, but they are all similar.
But different companies specify differences in WHEN this must be achieved by. Some have a blanket "stabilized by 1000 ft" for ALL approaches, some say "by 1000ft in IMC, and by 500 ft in VMC." I don't know what Asiana's rules are, no doubt it will come out in the investigation.
Here are some standard references that pretty much ANY commercial pilot will know and rely on..... if you are on the desired 3-degree nominal glidepath, at 5 miles you will be passing 1500 ft, you pass 1000ft just outside 3 miles, and 500ft at just under 2 miles.
So, to comply with 180 to 5 and be stable by 1000ft in this case would require losing 43kts while continuing a steady descent and configuring in the middle of it, all in less than 2 miles and less than a minute (180 kts is 3 miles a minute). This would require some pretty aggressive handling by someone very familiar with his plane, not someone still trying to get a feel for his new plane. Stable by 500ft would be a lot more do-able but still a challenge for a new-on-type pilot. In any case, some of the plots I've seen, if accurate, show that at 5 miles they were faster than 180kts and higher than 1500ft so it may have been nigh on impossible to be be stable at either gate. The question will be, why did the flying pilot elect to continue, and why did the instructor allow it to continue?
As many have said, saying "unable" might have helped although if they were already too high and too fast it wouldn't have made any difference and this is all moot anyway.
In the past when given a "180 kts to 5 miles" instruction I have said, "Unable, but I can give you 180 to 7 miles and 160 to 5," or similar and the controller has accepted that, but that might not be quite so easy for a non-fluent English speaker to do.
[QUOTE]I am sure that ATC did not impose this as a whim, in fact a couple of people have indicated that it is a common call for noise abatement reasons.
Well, where does that policy come from ?
Is it an airport operating requirement ? Is it just something that they would prefer ?/QUOTE]
It's not noise abatement. It's because there is following traffic that is catching you up. If they get too close, they will have to go around adding one extra plane to an already busy arrival pattern. This is probably not intuitive to non-pilots, but on approach the planes behind you are always catching you up. Why?..... because you always get the the point where you have to slow down before they get to their point where they have to slow down. Why doesn't ATC slow them all down at the same time?... Sounds like it might work, but it doesn't. You end up with a massively long conga line of planes flying slowly, wasting gas, and causing more delays. It's ATC's job to try and manage the problem efficiently, sometimes it doesn't quite work out for all sorts of reasons, hence the requests to keep the speed up. But ATC doesn't know the particulars of your plane's limitations and capabilities, that's the pilot's job and it's up to him to say "unable" when it's just not practical.
[QUOTE]There is a majority (but not universal) feeling that the ATC advisory "180 kts to 5nm"/4-degree approach was a possible contributory factor./QUOTE]
I'm not sure where you get the 4-degree approach thing from..... that wasn't in the instructions they were given and wouldn't be a normal thing anyway.
But I believe the 180 to 5 miles instruction might have contributed to an unstable approach, but it was not insurmountable. Ms. Hersman indicated that the speed limit for a 777 to select full flap was 160 kts. If you comply with the 180 till 5 instruction then you are accepting that you will not be in the landing configuration until quite late. In other words, you fly to 5 miles at 180 kts, then slow to below 160, then select full flap, then slow to target speed (in this case 137 kts). Only then, with the engines spooled up, and maintaining a stable target speed, on a stable glidepath to the touchdown zone with a rate of descent less than 1000fpm, can you consider the approach to be stabilized....my words are approximate, each company's SOPs will be very specific, but they are all similar.
But different companies specify differences in WHEN this must be achieved by. Some have a blanket "stabilized by 1000 ft" for ALL approaches, some say "by 1000ft in IMC, and by 500 ft in VMC." I don't know what Asiana's rules are, no doubt it will come out in the investigation.
Here are some standard references that pretty much ANY commercial pilot will know and rely on..... if you are on the desired 3-degree nominal glidepath, at 5 miles you will be passing 1500 ft, you pass 1000ft just outside 3 miles, and 500ft at just under 2 miles.
So, to comply with 180 to 5 and be stable by 1000ft in this case would require losing 43kts while continuing a steady descent and configuring in the middle of it, all in less than 2 miles and less than a minute (180 kts is 3 miles a minute). This would require some pretty aggressive handling by someone very familiar with his plane, not someone still trying to get a feel for his new plane. Stable by 500ft would be a lot more do-able but still a challenge for a new-on-type pilot. In any case, some of the plots I've seen, if accurate, show that at 5 miles they were faster than 180kts and higher than 1500ft so it may have been nigh on impossible to be be stable at either gate. The question will be, why did the flying pilot elect to continue, and why did the instructor allow it to continue?
As many have said, saying "unable" might have helped although if they were already too high and too fast it wouldn't have made any difference and this is all moot anyway.
In the past when given a "180 kts to 5 miles" instruction I have said, "Unable, but I can give you 180 to 7 miles and 160 to 5," or similar and the controller has accepted that, but that might not be quite so easy for a non-fluent English speaker to do.
[QUOTE]I am sure that ATC did not impose this as a whim, in fact a couple of people have indicated that it is a common call for noise abatement reasons.
Well, where does that policy come from ?
Is it an airport operating requirement ? Is it just something that they would prefer ?/QUOTE]
It's not noise abatement. It's because there is following traffic that is catching you up. If they get too close, they will have to go around adding one extra plane to an already busy arrival pattern. This is probably not intuitive to non-pilots, but on approach the planes behind you are always catching you up. Why?..... because you always get the the point where you have to slow down before they get to their point where they have to slow down. Why doesn't ATC slow them all down at the same time?... Sounds like it might work, but it doesn't. You end up with a massively long conga line of planes flying slowly, wasting gas, and causing more delays. It's ATC's job to try and manage the problem efficiently, sometimes it doesn't quite work out for all sorts of reasons, hence the requests to keep the speed up. But ATC doesn't know the particulars of your plane's limitations and capabilities, that's the pilot's job and it's up to him to say "unable" when it's just not practical.
Last edited by Bob Zuruncle; 16th Jul 2013 at 00:07.
You've obviously never flown a 777 or a A330 then.
250 kts at 3000' at 10 DME IS A PROBLEM. ( yes the 777 is a lot better than the 330 but even it would be a handful trying to fly a 3 deg slope and slow down at the same time from 210 kts back to VRef and stabilized by 1000' )
180 kts to 5 DME IS A PROBLEM.
In my outfit we would say "negative cannot..." To such a request. We could not lose 45 kts AND be configured and spun up in only 2 nm ( by a minimum of 1000' which is 3 nm ) IMPOSSIBLE.
250 kts at 3000' at 10 DME IS A PROBLEM. ( yes the 777 is a lot better than the 330 but even it would be a handful trying to fly a 3 deg slope and slow down at the same time from 210 kts back to VRef and stabilized by 1000' )
180 kts to 5 DME IS A PROBLEM.
In my outfit we would say "negative cannot..." To such a request. We could not lose 45 kts AND be configured and spun up in only 2 nm ( by a minimum of 1000' which is 3 nm ) IMPOSSIBLE.
Last edited by nitpicker330; 16th Jul 2013 at 00:36.
Hey Firewall - stop mincing words and tell us how you really feel 
Question for you Airbus drivers:
I'm somewhat familiar with their non-moving throttles - so what do you do in 'manual thrust' mode (or is there such a thing). Do you have to manipulate those little throttle nubs to control thrust? Does type A have something equivalent to throttle 'hold'?
Just wondering if the pilot flying was sufficiently tired/stressed and reverted back to what he was used to rather than flying what he was in.
Still wouldn't explain why the 'pilot monitoring' didn't notice that the throttles were at the idle stop while airspeed was decaying
BTW, I've never talked to a pilot that 'liked' the non-moving throttles (and had several tell me that's the only thing they dislike about the Airbus flight deck). Lots of pilots on this list - any of you actually like the non-moving throttle?
Question for you Airbus drivers:
I'm somewhat familiar with their non-moving throttles - so what do you do in 'manual thrust' mode (or is there such a thing). Do you have to manipulate those little throttle nubs to control thrust? Does type A have something equivalent to throttle 'hold'?
Just wondering if the pilot flying was sufficiently tired/stressed and reverted back to what he was used to rather than flying what he was in.
Still wouldn't explain why the 'pilot monitoring' didn't notice that the throttles were at the idle stop while airspeed was decaying
BTW, I've never talked to a pilot that 'liked' the non-moving throttles (and had several tell me that's the only thing they dislike about the Airbus flight deck). Lots of pilots on this list - any of you actually like the non-moving throttle?
In manual thrust you have to move the thrust levers just like a Boeing.
Yes I don't like the fact they don't move when you are using A/T. I don't like there is no feedback in the Sidesticks either.......
But the table is good
Yes I don't like the fact they don't move when you are using A/T. I don't like there is no feedback in the Sidesticks either.......
But the table is good
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Manual flight with autothrottle/ thrust is not a good idea, and I do not practice it, neither does my company. either all ON or all OFF. combining makes things jot only more complex, it confuses both the aircraft and the crew.
It seems more and more likely that this is one of the contributing factors.
Over and over, I see Captains and FO's blindly relying on the autothrottles, never putting their hands on the thrust levers to feel their reaction ( Boeing here) or at least monitoring the thrust trend and value ( on AB).
It seems more and more likely that this is one of the contributing factors.
Over and over, I see Captains and FO's blindly relying on the autothrottles, never putting their hands on the thrust levers to feel their reaction ( Boeing here) or at least monitoring the thrust trend and value ( on AB).
So what do you do prior to landing? Turn it all off? We click off the AP at 500ft on a visual and pull back power on RETARD. That goes against your line on thinking.
Gee if only there was something we could do when we find ourselves in an unstable approach situation........................ 
These incidents will keep on happening until someone can come up with some sort of procedure that allows us to 'throw' away an approach and start again.
These incidents will keep on happening until someone can come up with some sort of procedure that allows us to 'throw' away an approach and start again.
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Usually a normal pilot not all caught up with which button to push will realize at 1,000 ft if he has to fix it now or go around. At 500 ft you better have your STG or go around. At 100 ft a half mile out go around because you don't have your STG. Quite simple actually. Aviating 101. Ask an old timer if you can't find the issue.
"lower your level of automation!!!"
So simple yet so hard to implement. It's getting a little long in the tooth, but the youtube flick children of the magenta should be required viewing.
So simple yet so hard to implement. It's getting a little long in the tooth, but the youtube flick children of the magenta should be required viewing.
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All four pilots arrived back in Seoul on the 13th July.
Compare this to the shipping accident where Cosco Busan crashed into SFO Bay Bridge in 2007. That crew was held on US soil, without charges, for more than six months, I recall.
If it's too early to conclude in the Asiana investigation, surely it is also too early to absolve the pilots too?
What if there is proven gross negligence? Will prosecutors extradite?
Last edited by ross_M; 16th Jul 2013 at 02:30.
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despegue
We have the option as well and I usually do at 10K. My point is that AP off and AT on is not uncommon nor is it dangerous or confusing. If KISS is an issue, wouldn't you think leaving one on to focus on the other would be simpler to manage?
We have the option as well and I usually do at 10K. My point is that AP off and AT on is not uncommon nor is it dangerous or confusing. If KISS is an issue, wouldn't you think leaving one on to focus on the other would be simpler to manage?
If autopilot OFF, A/T ON is so complicated, how come that's how USN pilots do a lot of traps that way? It's not a problem; except I would submit on an Airbus where the throttles don't move.
All of this is an argument for HUDs, btw.
All of this is an argument for HUDs, btw.
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Interesting response BBL.
My points are fact and are beyond dispute (apart from one of the muppets saying we are too low at 4 sec before impact.... big &^$% deal ! Where was he in the loop for the previous 14 miles of divergent flight path)
You choose to counter with a guess at my TV viewing habits.
Infantile response. Tell me you have more to offer ?
Do you really need to be reminded that three innocent people have lost their lives as a result of this incompetence?
My points are fact and are beyond dispute (apart from one of the muppets saying we are too low at 4 sec before impact.... big &^$% deal ! Where was he in the loop for the previous 14 miles of divergent flight path)
You choose to counter with a guess at my TV viewing habits.
Infantile response. Tell me you have more to offer ?
Do you really need to be reminded that three innocent people have lost their lives as a result of this incompetence?
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Enough bullsh1t from general public and 100 hr private pilots
I have flown into KSFO numerous times with 21 years flying Boeing a/c, stated only to advise that this is not ill informed comment. Whilst the traveling public and pvt pilots are entitled to their opinion, this wild speculation does nothing to get to the crux of the accident.
1. The a/c was NOT given a slam dunk approach. Aligned on final at 4000 odd feet at 14 miles is not a slam dunk.
2. 230 kts at 14 miles is NOT a challenge.
3. Stabilised approach criteria was NON existant.
4. The a/c was on profile at 400 ft..... but with a ROD at close to double the stabilised equivalent, way outside the ballpark.
5. The 3 muppets up front said NOTHING. (I won't honour them with the term pilots)
6. A/T hold is a normal A/T sub mode. It only becomes a "trap" when you don't know what you are doing.
7. It is preferable that the guys up the pointy end know what they are *&$^ doing !
8. All ULH operations have a fatigue element. It is a professional's responsibility to mitigate that fatigue element by inflight rest, professional competence and knowing your game. The last two items were NON existent.
These morons masquerading as pilots deserve jail time, the charge professional incompetence.
Last edited by fire wall; 15th Jul 2013 at 14:39.
I have flown into KSFO numerous times with 21 years flying Boeing a/c, stated only to advise that this is not ill informed comment. Whilst the traveling public and pvt pilots are entitled to their opinion, this wild speculation does nothing to get to the crux of the accident.
1. The a/c was NOT given a slam dunk approach. Aligned on final at 4000 odd feet at 14 miles is not a slam dunk.
2. 230 kts at 14 miles is NOT a challenge.
3. Stabilised approach criteria was NON existant.
4. The a/c was on profile at 400 ft..... but with a ROD at close to double the stabilised equivalent, way outside the ballpark.
5. The 3 muppets up front said NOTHING. (I won't honour them with the term pilots)
6. A/T hold is a normal A/T sub mode. It only becomes a "trap" when you don't know what you are
doing. 7. It is preferable that the guys up the pointy end know what they are *&$^ doing !
8. All ULH operations have a fatigue element. It is a professional's responsibility to mitigate that fatigue element by inflight rest, professional competence and knowing your game. The last two items were NON existent.
These morons masquerading as pilots deserve jail time, the charge professional incompetence.
Last edited by fire wall; 15th Jul 2013 at 14:39.