Continental TurboProp crash inbound for Buffalo
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Quote by Lodown:
Using rudder ist not the appropriate mean in a stall. Still don't get it? Do we have to discuss this all over again? Never ever touch a rudder near stall.
Please look into the pprune-discussion about the A320 accident during the test flight over Perpignan:
Link
Dani
Rudder is not being used appropriately.
Please look into the pprune-discussion about the A320 accident during the test flight over Perpignan:
Link
Dani
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by pattern_is_full:
On the question of the Colgan FO putting the flaps back up - well, there's an old rule-of-thumb that if you do something, and everything immediate goes haywire, the first thing you do is to UNDO whatever your just did. Throttle back and the engine quits - the first thing you do is firewall the throttle. The FO moved the flaps to 15, and within a second the plane is upset - I can see the motivation to immediately "undo" the change in flap setting.
On the question of the Colgan FO putting the flaps back up - well, there's an old rule-of-thumb that if you do something, and everything immediate goes haywire, the first thing you do is to UNDO whatever your just did. Throttle back and the engine quits - the first thing you do is firewall the throttle. The FO moved the flaps to 15, and within a second the plane is upset - I can see the motivation to immediately "undo" the change in flap setting.
Dani
Cb
Sorry, I didn't read your post because I was busy typing. Nor am I interested in what happens at EK - is that Emirates? I have never flown for them and I never will, however I have operated a Q400 fairly extensively in the UK (might be easy to guess who for), and one day I might do so again.
I would suggest that if pilots are paid so poorly that they can't phone in sick, and can't afford to relocate to be near their base so have to sleep in the crew room that is the fault of the airline and the system in the states, where it can take 20 years to get a command on a CRJ and turboprop pilots (and indeed inexperienced RJ pilots) are paid subsistance wages.
I hope I'm wrong, but I suspect that this crew wasn't unusual, just unlucky. I fail to comprehend why you would have sympathy for experienced wide body long haul pilots who have to work when they are fatigued, but not with relatively inexperienced turbo prop pilots, but maybe I am missing something...
Sorry, I didn't read your post because I was busy typing. Nor am I interested in what happens at EK - is that Emirates? I have never flown for them and I never will, however I have operated a Q400 fairly extensively in the UK (might be easy to guess who for), and one day I might do so again.
I would suggest that if pilots are paid so poorly that they can't phone in sick, and can't afford to relocate to be near their base so have to sleep in the crew room that is the fault of the airline and the system in the states, where it can take 20 years to get a command on a CRJ and turboprop pilots (and indeed inexperienced RJ pilots) are paid subsistance wages.
I hope I'm wrong, but I suspect that this crew wasn't unusual, just unlucky. I fail to comprehend why you would have sympathy for experienced wide body long haul pilots who have to work when they are fatigued, but not with relatively inexperienced turbo prop pilots, but maybe I am missing something...
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Yes, I actually quite agree that we expect more from a professional pilot than from a burger flipper. Perhaps when the salaries are not much different the expectations should not be much different, but I atleast hope a pilot would do the right thing.
I think Company Induced Exhaustion would be a grand statement to make. There should be a box with CIE next to it on the unemployment forms.
As to sleep quality rather than just quantity, some physiological tests have shown that a night of disrupted sleep slows reaction time about the same as two shots of booze for breakfast does. Its possible to measure blood alcohol, its harder to measure alertness.
I think Company Induced Exhaustion would be a grand statement to make. There should be a box with CIE next to it on the unemployment forms.
As to sleep quality rather than just quantity, some physiological tests have shown that a night of disrupted sleep slows reaction time about the same as two shots of booze for breakfast does. Its possible to measure blood alcohol, its harder to measure alertness.
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The Turkish crews has been labelled as incompetentby by a number of posters.
The Colgan crew has, by many posters, been excused of their actions because of the perception of a tail stall.
What about if the two accidents were swapped, the Turkish crew on the Q400 and the the Colgan crew on the 747-800?
Would the comments be the same?
The Colgan crew has, by many posters, been excused of their actions because of the perception of a tail stall.
What about if the two accidents were swapped, the Turkish crew on the Q400 and the the Colgan crew on the 747-800?
Would the comments be the same?
Dani,
Sorry I missed yours as well. Somewhere back in the distant history of this thread it was mentioned (possibly by me but it was months ago and I can't be bothered to look) that the Q400 is not susceptable to tail plane stalls.
The powered elevator means that if the tailplane stalls (and Transport Canada required Bombardier to prove that it doesn't) the elevator cannot be sucked down so the control column won't move forward. One of Bombardiers flight test pilots gave an excellent post on here about how the certification air testing was carried out.
It even used to tell you in the AFM that the aircraft was not susceptable to tailplane stalls, and that was written 10 tears ago.
Sorry I missed yours as well. Somewhere back in the distant history of this thread it was mentioned (possibly by me but it was months ago and I can't be bothered to look) that the Q400 is not susceptable to tail plane stalls.
The powered elevator means that if the tailplane stalls (and Transport Canada required Bombardier to prove that it doesn't) the elevator cannot be sucked down so the control column won't move forward. One of Bombardiers flight test pilots gave an excellent post on here about how the certification air testing was carried out.
It even used to tell you in the AFM that the aircraft was not susceptable to tailplane stalls, and that was written 10 tears ago.
Using rudder ist not the appropriate mean in a stall.
You can not compare a Jet with swept wings and a Turboprop with a straight wing like to Q400.
Use of Rudder to avoid any slip is a perfect thing to do during a stall.
Inbalance
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Captain reacted to what he thought was a tail stall?
The only thing that makes sense to me is the captain was focused on the icing issue and reacted as if there had been a tail surface stall with lost of lift on the horizontal stabilizer. He knew the wings were relatively well protected from ice accumulation and was aware of previous tail stall incidents. He instinctively pulled back thinking it was a tail stall (unaware of the decaying airspeed issue).
Pulling back on the elevator is the proper reaction to a tail stall.
Every pilot with 8 hours training knows how to recover from a wing stall. You will never solo if you "pull back" as a reaction to a stalled wing. It's hard to image the captain doing this in any situation he thought was a wing stall.
Pulling back on the elevator is the proper reaction to a tail stall.
Every pilot with 8 hours training knows how to recover from a wing stall. You will never solo if you "pull back" as a reaction to a stalled wing. It's hard to image the captain doing this in any situation he thought was a wing stall.
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Hard to believe this is even being discussed. A Professional pilot will know when he/she is not up to piloting; flying while impaired or tired, or in any way unable to perform is the responsibility of the pilot. MEL always includes both pilots. If not healthy and sharp, one declines the trip. "The company requires it". NO, it does not. If arrangements cannot be made to arrive fit for duty, one doesn't fly. No salary or ego is worth a lacklustre performance with 47 souls relying on your word that you are fit. Fired? Sue. Help us all out, show some backbone and try to right the Blame game. Training? a little different, but if I worry about my lack of actual IMC on the Flight Deck, am I being ethical? Find other work. No one is entitled to risk the lives of others to fulfill a wish or a dream. I once knew a FO on a 747 classic who said he loved take offs, but landings always frightened him. He shared how ambivalent he felt about his skills, since Captaincy was looming. He was encouraged to take a Medical retirement.
There's minimums, and there's MINIMUMS.
There's minimums, and there's MINIMUMS.
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confusion over tailplane stall
quite simply, if the airspeed was below ref and the plane stalled, one should probably think that it was a conventional wing stall
pilots must be constantly aware of the plane and its aeronautical health.
did they think it was a tailplane stall...MAYBE!
but, did they talk about tailplane stall in the descent? or had this poor pilot and copilot just never ever seen a stick pusher in action. STICK PUSHERS aren't fitted to planes that don't need them.
IF they thought the tailplane stalled, then their training was bad.
IF they reacted to a conventional stall incorrectly, then they were fatigued.
AND in modern planes, the best way to raise a wing during a stall is : REDUCE ANGLE OF ATTACK AND USE AILERONS coordinated with rudder. please remember wash in and wash out...very old planes would have a problem using ailerons, but those planes had stalls that started near the tip of the wing and not the root.
PUSH forward was the answer here, full power, level the wings
bringing the flaps up was a mistake in this situation
talking about gear was a mistake too.
someone didn't understand something.
pilots must be constantly aware of the plane and its aeronautical health.
did they think it was a tailplane stall...MAYBE!
but, did they talk about tailplane stall in the descent? or had this poor pilot and copilot just never ever seen a stick pusher in action. STICK PUSHERS aren't fitted to planes that don't need them.
IF they thought the tailplane stalled, then their training was bad.
IF they reacted to a conventional stall incorrectly, then they were fatigued.
AND in modern planes, the best way to raise a wing during a stall is : REDUCE ANGLE OF ATTACK AND USE AILERONS coordinated with rudder. please remember wash in and wash out...very old planes would have a problem using ailerons, but those planes had stalls that started near the tip of the wing and not the root.
PUSH forward was the answer here, full power, level the wings
bringing the flaps up was a mistake in this situation
talking about gear was a mistake too.
someone didn't understand something.
Re “Never ever touch a rudder near stall.” (#1161)
There are few absolute truths in aviation; it would be better to qualify this with “follow the manufacturer’s recommendations”.
Note that aircraft certification (CS/FAR 25.203) discusses the use of all controls up to the time of stall and for recovery.
“25.203 (a) It must be possible to produce and to correct roll and yaw by unreversed use of aileron and rudder controls, up to the time the aeroplane is stalled. … … In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls.”
There is similar text in AC 25-7A Flight test guide for certification of transport category airplanes, which discusses test techniques and states in Section 6, d, 3, (viii):-
“Normal use of the lateral control must produce (or correct) a roll, and normal use of the directional control must produce (or correct) a yaw in the applied direction up to the point where the airplane is considered stalled. It must be possible to prevent or recover from a stall by normal use of the controls”.
If still unconvinced, check with a basic flying instructor about ‘stall turns’.
AC25-7A also has some good background to tail stalls – para 25.143 and/or search.
There are few absolute truths in aviation; it would be better to qualify this with “follow the manufacturer’s recommendations”.
Note that aircraft certification (CS/FAR 25.203) discusses the use of all controls up to the time of stall and for recovery.
“25.203 (a) It must be possible to produce and to correct roll and yaw by unreversed use of aileron and rudder controls, up to the time the aeroplane is stalled. … … In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls.”
There is similar text in AC 25-7A Flight test guide for certification of transport category airplanes, which discusses test techniques and states in Section 6, d, 3, (viii):-
“Normal use of the lateral control must produce (or correct) a roll, and normal use of the directional control must produce (or correct) a yaw in the applied direction up to the point where the airplane is considered stalled. It must be possible to prevent or recover from a stall by normal use of the controls”.
If still unconvinced, check with a basic flying instructor about ‘stall turns’.
AC25-7A also has some good background to tail stalls – para 25.143 and/or search.
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Correct, remember that you don't have a feeling of yaw! You only can note yaw by looking at your slipping indicator. Looking at it during a stall is not advisable.
Remember that planes in this class mainly roll during a stall, not yaw.
Thus using rudder is not recommended, in any aircraft I know. And I know a few turboprops, as well as bigger ones.
I think this rudder thing is also a "cultural item" in the US. There have been hull losses because of it earlier (remember AA over NY). We don't do such thing in old/new Europe. Rudder is for crosswind landings. Forget the rest.
Dani
Remember that planes in this class mainly roll during a stall, not yaw.
Thus using rudder is not recommended, in any aircraft I know. And I know a few turboprops, as well as bigger ones.
I think this rudder thing is also a "cultural item" in the US. There have been hull losses because of it earlier (remember AA over NY). We don't do such thing in old/new Europe. Rudder is for crosswind landings. Forget the rest.
Dani
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Clandestino wrote:
"Numbers I've used are from NTSB press advisory, dated march 25th. For those too lazy to click, here's the relevant quote:
Quote:
Originally Posted by National Transportation Safety Board
Preliminary airplane performance modeling and simulation efforts indicate that icing had a minimal impact on the stall speed of the airplane. The FDR data indicates that the stick shaker activated at 130 knots, which is consistent with the de-ice system being engaged. FDR data further indicate that when the stick shaker activated, there was a 25-pound pull force on the control column, followed by an up elevator deflection and increase in pitch, angle of attack, and Gs. The data indicate a likely separation of the airflow over the wing and ensuing roll two seconds after the stick shaker activated while the aircraft was slowing through 125 knots and while at a flight load of 1.42 Gs. The predicted stall speed at a load factor of 1 G would be about 105 knots. Airplane performance work is continuing.
And yet, nearly two months later there are still expert PPRuNers posting about ice, ice, ice..."
....perhaps because a lot of PPRUNERs (Professional Pilots!?!?) can't do aviation maths 101. C'mon everybody, repeat: An increase in load factor will cause an increase in stall speed. The stall speed increases by the square root of the load factor.
So, for a load factor of 1.42 increase the stall speed by about 1.2 times. For an expected stall speed of approx 105 KCAS for the weight and config, that gives an actual stall speed of 125 KCAS.
So, they were VERY slow. It did not take much of a load factor to go from a shaker firing 20 knots above the normal setting (somewhere between 1.1 and 1.0 time stall speed, I'm not sure of the exact number) to actually stalling the thing.
I still think that the way they were trained to do approaches to stalls, which probably required holding back pressure while the stick shaker was firing, had a lot to do with this.
Oh, and speaking of aviation 101, to the poster who seemed shocked by the big rudder inputs and believes using rudder is wrong:
The Dash8 has huge props that both turn in the same direction. At large angles of attack, large power changes bring significant yaw, due to P-Factor, torque, etc. etc. The crew was actually late on the rudder when adding power, hence the initial roll to the left. Full right rudder may well have been an over-reaction, but right rudder was definitely needed. Never do power-on stalls in a piston single?
"Numbers I've used are from NTSB press advisory, dated march 25th. For those too lazy to click, here's the relevant quote:
Quote:
Originally Posted by National Transportation Safety Board
Preliminary airplane performance modeling and simulation efforts indicate that icing had a minimal impact on the stall speed of the airplane. The FDR data indicates that the stick shaker activated at 130 knots, which is consistent with the de-ice system being engaged. FDR data further indicate that when the stick shaker activated, there was a 25-pound pull force on the control column, followed by an up elevator deflection and increase in pitch, angle of attack, and Gs. The data indicate a likely separation of the airflow over the wing and ensuing roll two seconds after the stick shaker activated while the aircraft was slowing through 125 knots and while at a flight load of 1.42 Gs. The predicted stall speed at a load factor of 1 G would be about 105 knots. Airplane performance work is continuing.
And yet, nearly two months later there are still expert PPRuNers posting about ice, ice, ice..."
....perhaps because a lot of PPRUNERs (Professional Pilots!?!?) can't do aviation maths 101. C'mon everybody, repeat: An increase in load factor will cause an increase in stall speed. The stall speed increases by the square root of the load factor.
So, for a load factor of 1.42 increase the stall speed by about 1.2 times. For an expected stall speed of approx 105 KCAS for the weight and config, that gives an actual stall speed of 125 KCAS.
So, they were VERY slow. It did not take much of a load factor to go from a shaker firing 20 knots above the normal setting (somewhere between 1.1 and 1.0 time stall speed, I'm not sure of the exact number) to actually stalling the thing.
I still think that the way they were trained to do approaches to stalls, which probably required holding back pressure while the stick shaker was firing, had a lot to do with this.
Oh, and speaking of aviation 101, to the poster who seemed shocked by the big rudder inputs and believes using rudder is wrong:
The Dash8 has huge props that both turn in the same direction. At large angles of attack, large power changes bring significant yaw, due to P-Factor, torque, etc. etc. The crew was actually late on the rudder when adding power, hence the initial roll to the left. Full right rudder may well have been an over-reaction, but right rudder was definitely needed. Never do power-on stalls in a piston single?
Teaching the pilots to recover from fully blown stall in stick-pusher equipped aeroplanes would largely be an exercise in futility. Pushers are there for a good reason and overriding them has very high probability of turning lethal. Too bad one can be completely ignorant of the fact and still score 85% needed to pass Aerodynamics exam - sorry, I meant "Principles of flight".
Only recently I've noticed that Colgan is a subsidiary of Pinnacle. Perhaps we could talk about corporate culture, dudes?
Only recently I've noticed that Colgan is a subsidiary of Pinnacle. Perhaps we could talk about corporate culture, dudes?
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Dani.
Go rent a single engine prop plane. Or any multiengine prop where the props turn in the same direction. Do some power on (full) stalls with your feet off the pedals. Make sure you have lots of altitude to recover. Oh, and maybe a parachute.
Now rent a Dash8 and try it. The Dash8, being a transport, should recover from the resulting roll by using the yoke only. But you'll be fighting a massive yawing tendancy at the same time, which is tending to increase the roll that you are attempting to correct. So, without rudder, you'll be fighting the airplane and the recovery will take much longer.
Last edited by q100; 14th May 2009 at 22:03. Reason: clarity
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Tail plane stall:
I didn't say it was a tail plane stall, I said they were maybe in a mindset of tail plane stall. Remember that they were relativly new on type and I assume that they flew other/smaller turboprops before.
So in a situation of heavy stress you tend to go back to what you know best, and that maybe the program "tail plane stall". At least when they retracted the flaps. So the fact that they retracted the flaps was not a completly fooling issue, it was just an act because of a wrong reason.
Dani
I didn't say it was a tail plane stall, I said they were maybe in a mindset of tail plane stall. Remember that they were relativly new on type and I assume that they flew other/smaller turboprops before.
So in a situation of heavy stress you tend to go back to what you know best, and that maybe the program "tail plane stall". At least when they retracted the flaps. So the fact that they retracted the flaps was not a completly fooling issue, it was just an act because of a wrong reason.
Dani
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q100, you're right, you think of small aircraft. We here think of airliners. A Q400 is a completly different kind of animal than your Cessna 152.
Of course you need rudder for thrust increase. But not for stall recovery, well it may happen at the same time, but not for the same reason!
Dani
Of course you need rudder for thrust increase. But not for stall recovery, well it may happen at the same time, but not for the same reason!
Dani
Dani.
Go rent a single engine prop plane. Or any multiengine prop where the props turn in the same direction. Do some power on stalls with your feet off the pedals. Make sure you have lots of altitude to recover. Oh, and maybe a parachute.
Today 21:51
Go rent a single engine prop plane. Or any multiengine prop where the props turn in the same direction. Do some power on stalls with your feet off the pedals. Make sure you have lots of altitude to recover. Oh, and maybe a parachute.
Today 21:51
And if somebody is unable to look at the turn indicator during a stall in IMC better give back their licence.
Inbalance
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Dani,
I have over 5000 hours in Dash8s. See my tongue-in-cheek user name.
One of my major pet peeves is when the other pilot does not use rudder and/or rudder trim and we fly around in a slip all day long. Grrr.
I have over 5000 hours in Dash8s. See my tongue-in-cheek user name.
One of my major pet peeves is when the other pilot does not use rudder and/or rudder trim and we fly around in a slip all day long. Grrr.
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So enlighten me:
Does your (A)OM say that Bombardier recommends using rudder during a stall?
Of course you need rudder for power changes, and for engine failures.
I have more than 6000 hrs on Saab 2000, the most powerful and fastest turboprop in the world. Still better performance than a Q400. I hate to show off but you started.
You simply try to belittle my argument, you don't argue to find the truth. Which is: Don't use rudder for stall recovery.
Inbalance, looking at the slip indicator during stall is not a good thing. Because yaw is happening rather abrupt and randomly. You won't be able to control the yaw during a stall (if the power is constant on all engines). The danger of crossing controls is much bigger than you could correct irregular yaw oscillations during an impending stall. Thus don't use the rudder.
Dani
Does your (A)OM say that Bombardier recommends using rudder during a stall?
Of course you need rudder for power changes, and for engine failures.
I have more than 6000 hrs on Saab 2000, the most powerful and fastest turboprop in the world. Still better performance than a Q400. I hate to show off but you started.
You simply try to belittle my argument, you don't argue to find the truth. Which is: Don't use rudder for stall recovery.
Inbalance, looking at the slip indicator during stall is not a good thing. Because yaw is happening rather abrupt and randomly. You won't be able to control the yaw during a stall (if the power is constant on all engines). The danger of crossing controls is much bigger than you could correct irregular yaw oscillations during an impending stall. Thus don't use the rudder.
Dani