The Hazards of Going on Autopilot...

They left out the part about when the stall warning goes off you do not pull back.
 
Not sure the AP had much to do with this. Pilot error and lack of stick and rudder experience. Pull stick back in a stall? :mad2: :no:
 
Geico266 said:
Not sure the AP had much to do with this. Pilot error and lack of stick and rudder experience. Pull stick back in a stall? :mad2: :no:
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Why is it that this keeps happening?
Same thing in Air France (I know other factors)

Seems a lot of commercial pilots pull back when stalling in NTSB reports.
 
SixPapaCharlie said:
Why is it that this keeps happening?
Same thing in Air France (I know other factors)

Seems a lot of commercial pilots pull back when stalling in NTSB reports.
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Air France had a complicating factor in that he had the nose so high, the stall warning system didn't believe the indications and shut up. When the pilot put the nose down and started recovering, the AoA entered back into the realm of believable and the stall warning system went off again where he promptly pulled the stick back again to shut off the stall warning. That whole scene fried his capability to think.
 
I used to be impressed when a guy said he was a 20,000hr+ airline pilot. Not anymore. Don
 
Henning said:
Air France had a complicating factor in that he had the nose so high, the stall warning system didn't believe the indications and shut up. When the pilot put the nose down and started recovering, the AoA entered back into the realm of believable and the stall warning system went off again where he promptly pulled the stick back again to shut off the stall warning. That whole scene fried his capability to think.
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I keep wondering if the regime of emergency situation training in the simulator contributes to this reaction.

I have no direct experience to draw on but I've been led to believe that in modern fly by wire aircraft when operating in one of its 'normal' modes, that stall avoidance is automatic. That would suggest that recovery from many abnormal attitudes could be accomplished by commanding full power, leveling the wings, and full pitch up if the control system is operating in 'normal' mode.

Do that enough times in the simulator and voilà.

(I hadn't heard of the AOA being too high to set off the stall warning before in the Air France accident but I did understand that the control system had gone into some abnormal 'direct control' mode because it knew it didn't have enough information to provide all the fail safe functions it has in 'normal' modes. Both conditions are definitely brain fryers!)
 
I thought the AirFrance accident was because the FO had the stick pulled back and the left seat pilot who had relieved the Capt. had his stick forward and they simply canceled out leaving the aircraft in a nose high stalled AOA until the aircraft hit the ocean like a flat rock.
1. Frozen airspeed pitot
2. No interconnection between the sticks mechanically.
3. FO holding wrong stick position
4. Left seat performing proper recovery input
5. Flyby wire cancled proper stick input from left seat because right seat was opposite.
 
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Always have loved the New Yorker. All that said, commercial air travel in the US is still safer than just about any other form of conveyance save walking.
 
SixPapaCharlie said:
Seems a lot of commercial pilots pull back when stalling in NTSB reports.
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flyingron said:
They left out the part about when the stall warning goes off you do not pull back.
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Unfortunately this was what was being taught in the simulator. Stall recoveries were being taught a performance maneuvers, so when the airplane reaches first indication of a stall the pilot holds the nose up (to prevent loss of altitude) and applies go around power, recovers on altitude and a predetermined airspeed. This was done straight ahead and turning as well, in various configurations.

After Colgan it was realized that stalls should be taught as, well, stalls and recovery should be taught the conventional way.
 
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steingar said:
Always have loved the New Yorker. All that said, commercial air travel in the US is still safer than just about any other form of conveyance save walking.
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I'll bet it's safer than walking in many places.
 
The plane lost cabin pressurization. Had he recognized early symptoms, headache, nausea, fatigue, before losing consciousness he could have either taken control and descended, or set the altimeter to force the AP down, or set an altitude bug to do the same thing.

Obviously no one will ever know what happened. Other than he lost consciousness, the escort saw his chest moving/breathing but he was out cold. Likewise, his wife must have been out too.
 
CTLSi said:
The plane lost cabin pressurization. Had he recognized early symptoms, headache, nausea, fatigue, before losing consciousness he could have either taken control and descended, or set the altimeter to force the AP down, or set an altitude bug to do the same thing.

Obviously no one will ever know what happened. Other than he lost consciousness, the escort saw his chest moving/breathing but he was out cold. Likewise, his wife must have been out too.
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Wrong thread Chuckles........:rolleyes:
 
Henning said:
Air France had a complicating factor in that he had the nose so high, the stall warning system didn't believe the indications and shut up. When the pilot put the nose down and started recovering, the AoA entered back into the realm of believable and the stall warning system went off again where he promptly pulled the stick back again to shut off the stall warning. That whole scene fried his capability to think.
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I agree that there is a lot of "Pilot Error" in that accident, BUT . . .

If I recall correctly, even though the angle of attack was in the vicinity of 40 degrees, the actual pitch attitude of the airplane was something like 15 degrees nose up relative to the horizon. That is a normal pitch attitude on a normal max power takeoff. I can understand where that could lead to a certain amount of confusion.

Fortunately, or unfortunately, as the case may be, a lot of the typical stall characteristics that we are accustom to in light airplanes has been designed out of the new generation transport planes. In the case of Airbus, there is apparently no airframe buffet or any other airframe clues as to whether or not the airplane is in a stall.

And yes, the stall recovery training that we received at the time was most likely a contributing factor as to the outcome of this accident.
 
Bill Watson said:
I have no direct experience to draw on but I've been led to believe that in modern fly by wire aircraft
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We are talking about Airbus, here. Boeing's fly by wire has a bit of a different philosophy.

when operating in one of its 'normal' modes,
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There is only one. It is called "Normal Law". The degraded modes are called "Alternate Law" and "Direct Law".

that stall avoidance is automatic.
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It is automatic in that it is not possible to stall the airplane in "Normal Law".

That would suggest that recovery from many abnormal attitudes could be accomplished by commanding full power, leveling the wings, and full pitch up if the control system is operating in 'normal' mode.
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True.
Do that enough times in the simulator and voilà.
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It does tend to be negative training, doesn't it?

(I hadn't heard of the AOA being too high to set off the stall warning before in the Air France accident
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Well, if you think about it, you wouldn't want the stall warning to be going off during takeoff and landing rollouts. That was the rationale for the stall warning being deactivated below 60 knots. We now know that there would have been better design options than that.

but I did understand that the control system had gone into some abnormal 'direct control' mode
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Its been awhile and I don't remember, but I think it only went into "Alternate Law", not all the way to "Direct Law" but now I am talking semantics.

because it knew it didn't have enough information to provide all the fail safe functions it has in 'normal' modes. Both conditions are definitely brain fryers!)
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Yeah, they are, if you don't fully understand what is happening. In that regard, training was as much at fault as the pilots were.
 
Sleepingsquirrel said:
I thought the AirFrance accident was because the FO had the stick pulled back and the left seat pilot who had relieved the Capt. had his stick forward and they simply canceled out leaving the aircraft in a nose high stalled AOA until the aircraft hit the ocean like a flat rock.
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The control inputs are algebraically summed. So the left stick would in fact cancel out the right stick when they were at opposite ends of travel. HOWEVER, when the left seat guy pushed forward, the elevator would have gone to neutral, instead of full up. That SHOULD have changed the pitch at least a little.

ALSO, there is a button on the control stick that, when pushed, takes control from the other stick. The left seat guy neglected to push that button when he tried to take control.

1. Frozen airspeed pitot
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I didn't think that was a factor on this particular accident. Might have been, I just don't recall.

2. No interconnection between the sticks mechanically.
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There are other cues.

3. FO holding wrong stick position
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Hindsight being 20/20 yes he was. He didn't think so at the time.

4. Left seat performing proper recovery input

5. Flyby wire cancled proper stick input from left seat because right seat was opposite.
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Both of those are related to the fact that the left seater did not push the override button.
 
Sleepingsquirrel said:
I thought the AirFrance accident was because the FO had the stick pulled back and the left seat pilot who had relieved the Capt. had his stick forward and they simply canceled out leaving the aircraft in a nose high stalled AOA until the aircraft hit the ocean like a flat rock.
1. Frozen airspeed pitot
2. No interconnection between the sticks mechanically.
3. FO holding wrong stick position
4. Left seat performing proper recovery input
5. Flyby wire cancled proper stick input from left seat because right seat was opposite.
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No sir. The right seat pilot had the stick down to about 12,000' when he said 'This is really happening isn't it?" That's when his hand trembled and he dropped a wing. At that point the left seater grabbed the stick recovering it and the right seater said "Yeah, you take it." And then the left seater, rather than putting the nose down to recover, just went back to holding a near wings level controlled stall all the way to the water.

BTW, IIRC the pitot cleared not long after the event initiated. The one pitot was the only bad indication on the plane, everything else worked perfect, but that failure set it all in motion.
 
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Henning said:
Air France had a complicating factor in that he had the nose so high, the stall warning system didn't believe the indications and shut up. When the pilot put the nose down and started recovering, the AoA entered back into the realm of believable and the stall warning system went off again where he promptly pulled the stick back again to shut off the stall warning. That whole scene fried his capability to think.
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They still had an attitude indicator, yes? Was there any indication that they looked at it?
 
teejayevans said:
They still had an attitude indicator, yes? Was there any indication that they looked at it?
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Yep, everything worked except for a brief minute the right seat pitot. It was only that they had #2 AP which takes its signal from that pitot that kicked off when losing the indication that went down. They were thinking that the control system was screwed up because when he put the nose down, the stall warning kicked in. Even the captain was struck dumb, all three of them looking at a panel that was telling them the plane was stalled, but they never realized it.
 
In the case of Birgenair 301, it was the captain who pull the plane into a stall, the 2 other pilots recognized the stall, but didn't take control because his was the senior officer. Similarly, is was an erroneous ASI reading that caused it all.
 
Are all these stalls happening in IMC?

Can't a captain just look out the window and fly and ignore the technology if it isn't IMC?

Take it easy on me. I am jet ignorant.
 
txflyer said:
Are all these stalls happening in IMC?

Can't a captain just look out the window and fly and ignore the technology if it isn't IMC?

Take it easy on me. I am jet ignorant.
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AF 441 and Birgenair 301 were at night, over the ocean.
 
RotorAndWing said:
Unfortunately this was what was being taught in the simulator. Stall recoveries were being taught a performance maneuvers, so when the airplane reaches first indication of a stall the pilot holds the nose up (to prevent loss of altitude) and applies go around power, recovers on altitude and a predetermined airspeed. This was done straight ahead and turning as well, in various configurations.

After Colgan it was realized that stalls should be taught as, well, stalls and recovery should be taught the conventional way.
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Yes, that. :yes:

It's more like flying a game than an airplane in a way. Everything is fine as long as every abnormal situation is accurately simulated and taught. Miss something and eventually someone will find the gap.
 
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