Stall Recovery Technique
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To recover, the application of full power and control column centrally forward whilst maintaining balance is correct. But do not move the column further forward than the point at which the stall warning/ident ceases. Then level wings and recover from any descent - which, if prompt action has been taken at the incipient stage, should be almost zero.
The above absolutely reflects what I was asked to do in the USA when checking out for rentals.
When I didn't know the US philosophy, the first time I was asked to recover from a stall (no mention of power on or off), I did a power off with a height loss of about 150 feet and scared the instructor ****less. (He was gracious enough to say it was his fault for not briefing exactly what he wanted, but I did buy him a beer later!)
On his next briefing, he asked me to 'relax the back pressure slighly' and add full power, then explaining that their philosophy was to guard against reaction based aggressive nose down inputs near the ground.
One can see how the 'relax the back pressure slightly' could suffer from the Chinese whispers effect and become 'hold attitude.'
I'm not an instructor and am certainly nowhere near as experienced at flying as other people on the thread, but i do understand human nature and the use of language pretty well.
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UV
In what' scenario would you want flaps high level and what do you consider high level ? Obviously you may consider a high altitude airport as high level ?
I have not seen any indication in the manuals of a flap altitude restriction.
Regarding the CAA doc I stress the fact that any manufacturer recommendation overrides their own.
With the citation it isto hold attitude and power out.
Obviously different horses for different courses engine out in a stall I would use my instincts and pitch the nose !
Pace
In what' scenario would you want flaps high level and what do you consider high level ? Obviously you may consider a high altitude airport as high level ?
I have not seen any indication in the manuals of a flap altitude restriction.
Regarding the CAA doc I stress the fact that any manufacturer recommendation overrides their own.
With the citation it isto hold attitude and power out.
Obviously different horses for different courses engine out in a stall I would use my instincts and pitch the nose !
Pace
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I may be missing something here, but I thought the fundamental difference between a Citation and a standard GA aircraft is that the Citation is a jet.
Powering out of a stall in a single engine prop aircraft would involve a large increase in torque, producing a sudden increase in yaw - leading to an out of balance situation which produces a dramatic wing drop. I presume this wouldn't happen in a Citation ?
Powering out of a stall in a single engine prop aircraft would involve a large increase in torque, producing a sudden increase in yaw - leading to an out of balance situation which produces a dramatic wing drop. I presume this wouldn't happen in a Citation ?
I have not seen any indication in the manuals of a flap altitude restriction
In what' scenario would you want flaps high level and what do you consider high level
Stalling exercises too! Usually at F120.
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I'm glad BEagle has mentioned the point of how much do you apply forward stick, as it seems to be a misconception to some people that just pushing the control column forward 'will do'
Also, correct me if I'm wrong, but I always thought that stick shakers were installed on aircraft whose stall characteristics, (if allowed to develop, whether accidentally or on purpose), are such, that it would be extremely difficult if not impossible, to get out of a fully developed stall. For example, a deep or flat stall situation, (Sometimes seen in aircraft with swept wings)?
If that is so, then surely the 'recovery' techniques described are not recovery at all, but preventative, instigated by the stick shaker?
ariel
Also, correct me if I'm wrong, but I always thought that stick shakers were installed on aircraft whose stall characteristics, (if allowed to develop, whether accidentally or on purpose), are such, that it would be extremely difficult if not impossible, to get out of a fully developed stall. For example, a deep or flat stall situation, (Sometimes seen in aircraft with swept wings)?
If that is so, then surely the 'recovery' techniques described are not recovery at all, but preventative, instigated by the stick shaker?
ariel
Ariel - not quite, stick shakers are a common stall warner on larger aeroplanes, it is stick pushers that tend to get mandated on aeroplanes with poor stalling characteristics.
Fitting both is however fairly common - BAC 1-11 and Jetstream I think both have both.
G
Fitting both is however fairly common - BAC 1-11 and Jetstream I think both have both.
G
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Jetstream stick shaker goes at 1.1 Vs 1g and push goes at 1.05 Vs 1g and its done off a flap on the leading edge on the j31/32 its done on a AofA sensor on the J41
The shacker goes very occasionally in the flare but more often with full reverse on landing. On a C of A flight check the stick push is rather an eye opener, it gives you 40 deg nose down. I have stalled the 31/32 a couple of times and the stall is less of an issue with the stick push out than when it triggers. The J41 is more forgiving with the safety systems turned on and off.
The J41 is more docile of the 2 in a fully developed stall.
Stick push came in for aircraft with high t tails when the dirty air off the wings blanked the elevators. The authorites like stick pushes and most aircraft are fitted with them for example the 747 doesn't need it for a FAA cert but does for a EU cert
The shacker goes very occasionally in the flare but more often with full reverse on landing. On a C of A flight check the stick push is rather an eye opener, it gives you 40 deg nose down. I have stalled the 31/32 a couple of times and the stall is less of an issue with the stick push out than when it triggers. The J41 is more forgiving with the safety systems turned on and off.
The J41 is more docile of the 2 in a fully developed stall.
Stick push came in for aircraft with high t tails when the dirty air off the wings blanked the elevators. The authorites like stick pushes and most aircraft are fitted with them for example the 747 doesn't need it for a FAA cert but does for a EU cert
There is a body of opinion in the aircraft certification community that the stick-push operating speed then becomes declared as Vs.
The implications of that are significant because this then inevitably increases 1.3Vs, and thus field lengths.
G
The implications of that are significant because this then inevitably increases 1.3Vs, and thus field lengths.
G
Moderator
A couple of observations - at high alpha, lots of sudden power/thrust
(a) usually is destabilising in pitch and may create LSS problems - prop or jet. This is especially so on, for example, piston to turboprop conversions where the prop disc moves further forward for balance and provides an increased arm for the prop normal force moment. With underslung jets, one can add the low thrust line to the destabilising problems.
(b) may generate undesirable yaw - even on single engine machines. This increases the risk of a departure into spin - prop
Unless immediate ground contact be a problem, there is a lot to recommend a technique akin to the usual certification recovery variations - simultaneously rudder to constrain further yaw/pitch down, unstall, wings level, power up and then a recovery to normal flight.
While the larger ME turboprop aeroplanes usually can do the throttles up-power out of stall-trick (used to be good fun on the L188) it always appears to me to be a philosophical and knowledge mismatch between the certification and operations folk to emphasise altitude loss as the principal driver. If immediate ground contact is the present risk, then the risk of LOC is acceptable - if not the former, then why accept the latter ?
(a) usually is destabilising in pitch and may create LSS problems - prop or jet. This is especially so on, for example, piston to turboprop conversions where the prop disc moves further forward for balance and provides an increased arm for the prop normal force moment. With underslung jets, one can add the low thrust line to the destabilising problems.
(b) may generate undesirable yaw - even on single engine machines. This increases the risk of a departure into spin - prop
Unless immediate ground contact be a problem, there is a lot to recommend a technique akin to the usual certification recovery variations - simultaneously rudder to constrain further yaw/pitch down, unstall, wings level, power up and then a recovery to normal flight.
While the larger ME turboprop aeroplanes usually can do the throttles up-power out of stall-trick (used to be good fun on the L188) it always appears to me to be a philosophical and knowledge mismatch between the certification and operations folk to emphasise altitude loss as the principal driver. If immediate ground contact is the present risk, then the risk of LOC is acceptable - if not the former, then why accept the latter ?
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It's worth pointing out that the Flight Crew Operating Manual for (for example) the A320 very strongly makes the point that reducing angle of attack is the primary concern and that power should NOT be applied during the recovery as the pitch up moment that the underslung engines create may make it difficult for the pilot to reduce the AOA.
Of course, if the aeroplane has a pitch DOWN moment with power (like the CRJ series for example) then a simultaneous application of power and reduction in pitch may be appropriate I would suggest, as it would asist with the reduction in AOA. An element of type-specificness (if there is such a word) is obviously necessary.
However, reduction of Angle of Attack will always be the chief aim. That said, I have seen many instructors on light aircraft who will advocate an excessive nose attitude reduction that results in significant (and alarming) loss of height. When I was flying the VC10 on 10 sqn, I did a PPL skills test on a PA28 and the examiner gave me a hard time because I used a small (but sufficient) nose attitude reduction to recover with minimal height loss from an incipient stall. He, it would appear, would have preferred me to do an impression of a Stuka!
Of course, if the aeroplane has a pitch DOWN moment with power (like the CRJ series for example) then a simultaneous application of power and reduction in pitch may be appropriate I would suggest, as it would asist with the reduction in AOA. An element of type-specificness (if there is such a word) is obviously necessary.
However, reduction of Angle of Attack will always be the chief aim. That said, I have seen many instructors on light aircraft who will advocate an excessive nose attitude reduction that results in significant (and alarming) loss of height. When I was flying the VC10 on 10 sqn, I did a PPL skills test on a PA28 and the examiner gave me a hard time because I used a small (but sufficient) nose attitude reduction to recover with minimal height loss from an incipient stall. He, it would appear, would have preferred me to do an impression of a Stuka!
Do a Hover - it avoids G
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BEags
It seems to me (and I suspect to you) that a lot of people are talking about ‘stall recovery’ from a situation where the wings concerned were not actually stalled.
The idea of powering out of a true stall is dangerous talk. Indeed very dangerous talk if the aircraft happens to have a low thrust line.
Powering out from a situation where you are approaching the alpha at which a stall is going to happen if you continue to do what you have been doing is quite another thing and of course no problem.
I read the article Pace asked somebody to read it had this in it:
“Obviously, swept wings would have flown like swept wings, which means challenging stall characteristics, relatively high approach speeds with a tendency toward dutch-roll problems during those “hot” approaches.”
Sounds like something written in the 1950s (although it had a 1986 publishing date on it).
Today it reads like a second hand salesman’s pitch when trying to justify a design’s lack of sweep. Today educated people know how to design swept wings that are as benign at high alpha as you could wish for.
It seems to me (and I suspect to you) that a lot of people are talking about ‘stall recovery’ from a situation where the wings concerned were not actually stalled.
The idea of powering out of a true stall is dangerous talk. Indeed very dangerous talk if the aircraft happens to have a low thrust line.
Powering out from a situation where you are approaching the alpha at which a stall is going to happen if you continue to do what you have been doing is quite another thing and of course no problem.
I read the article Pace asked somebody to read it had this in it:
“Obviously, swept wings would have flown like swept wings, which means challenging stall characteristics, relatively high approach speeds with a tendency toward dutch-roll problems during those “hot” approaches.”
Sounds like something written in the 1950s (although it had a 1986 publishing date on it).
Today it reads like a second hand salesman’s pitch when trying to justify a design’s lack of sweep. Today educated people know how to design swept wings that are as benign at high alpha as you could wish for.
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John
Having come from a multi piston invironment my instincts are to pitch and power out of a stall.
In a flight test the examiner blew my head off when I reverted to my instinctive reaction to a stall and made me do the procedure again holding the nose level going for thrust and powering out.
When I pitched out the altitude loss was far greater than the manufacturers and examiners method.
Obviously different aircraft require different methods hence I presume the CAA noting that the manufacturers recommendations over ride their own advice.
Pace
Having come from a multi piston invironment my instincts are to pitch and power out of a stall.
In a flight test the examiner blew my head off when I reverted to my instinctive reaction to a stall and made me do the procedure again holding the nose level going for thrust and powering out.
When I pitched out the altitude loss was far greater than the manufacturers and examiners method.
Obviously different aircraft require different methods hence I presume the CAA noting that the manufacturers recommendations over ride their own advice.
Pace
For what it's worth, I'm in the middle of a test programme at the moment looking at different single engine light aeroplanes and their responses to four different stall recoveries:
- Simultaneous full power and pitch (what the CAA recommend)
- Pitch, then full power immediately the wing appears unstalled (what the FAA recommend)
- Pitch, 2 second pause, full power
- Full power holding stick back, 2 second pause, pitch nose-down.
A lot of work to be done yet, and a number of common types we want to fly. However, we've flown 8 types so far (9, but we've not analysed data on the 9th yet).
All recovered first time every time to both the CAA and FAA recoveries, the CAA version however averaged 2/3 the height loss in recovery of the FAA recovery. The 2 second pause didn't add much height loss compared to the FAA method but was much more comfortable to fly with the aeroplane "feeling" far more controllable.
On a couple of occasions aeroplanes recovered with power only gave a really lovely minimal height loss recovery. On rather more occasions (and this could depend upon flaps) other types did show secondary departure with a few knife-edge rolls or incipient spins when power was applied first without pitch.
Much more work to be done, more aeroplanes to be flown, and a paper to be go through peer review before we publish this - so a year or so more than likely. But it seemed pertinent to the discussion.
G
- Simultaneous full power and pitch (what the CAA recommend)
- Pitch, then full power immediately the wing appears unstalled (what the FAA recommend)
- Pitch, 2 second pause, full power
- Full power holding stick back, 2 second pause, pitch nose-down.
A lot of work to be done yet, and a number of common types we want to fly. However, we've flown 8 types so far (9, but we've not analysed data on the 9th yet).
All recovered first time every time to both the CAA and FAA recoveries, the CAA version however averaged 2/3 the height loss in recovery of the FAA recovery. The 2 second pause didn't add much height loss compared to the FAA method but was much more comfortable to fly with the aeroplane "feeling" far more controllable.
On a couple of occasions aeroplanes recovered with power only gave a really lovely minimal height loss recovery. On rather more occasions (and this could depend upon flaps) other types did show secondary departure with a few knife-edge rolls or incipient spins when power was applied first without pitch.
Much more work to be done, more aeroplanes to be flown, and a paper to be go through peer review before we publish this - so a year or so more than likely. But it seemed pertinent to the discussion.
G
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I believe Pace is describing the recovery from incipient stall (the shaker) in which case the wing has not yet stalled. Adding power in a Citation in those circumstances will indeed "power out" of the impending stall without loss of altitude, and it is therefore a reasonable strategy, especially close to the ground. An additional item on the list mentioned by others is that if the wing is "clean", selecting the first stage of flap is also one of the memory items. This immediately reduces the angle of attack of the wing - combined with the addition of power, recovery is instant and assured.
On the other hand, with a fully developed stall in a Citation, unless you have a death wish and have cranked the trim all the way back, you WILL be pulling firmly on the control column (and descending). Easing the back pressure will quickly reduce the AOA and unstall the wing - but we will still be descending until we add power and let it accelerate.
On the other hand, with a fully developed stall in a Citation, unless you have a death wish and have cranked the trim all the way back, you WILL be pulling firmly on the control column (and descending). Easing the back pressure will quickly reduce the AOA and unstall the wing - but we will still be descending until we add power and let it accelerate.
Do a Hover - it avoids G
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CJ Driver
I agree with you. In my view so called stall recovery training in aircraft and sims is about recovering from the incipient stage. Sadly the terrible emphasis on minimising height loss has had some very bad results recently.
There are signs that the 'authorities' are starting to realise this.
There are signs that the 'authorities' are starting to realise this.
Though I don't want to appear to second guess the pilot's choice to stretch a glide, and thus stall the plane, to get to the intended landing spot, I suggest that a much better landing would have been possible if control of the aircraft were to have been maintained in unstalled flight. Perhaps the pilot had absolutely no choice, but to stretch to there, and if so, fair enough, but this aircraft flew quite a long way in partially stalled flight, and cross the final approach obsticle with excess altitude, which might have been better exchanged for more controlled flight, and a lower impact landing.
If you have stalled "close to the ground" your duty as the pilot is to recover to controlled flight without hitting the ground. Recovering to minimum altitude loss is foolish, and riskes a worse situation if poorly executed, with a greater altitude loss than otherwise would have occurred. I'd rather brush treetops in controlled flight, than descend into them in stalled flight, from a botched effort to minimize altitude loss.
Once you give up the power off energy associated with speed, it's hard to get back, without loosing a whole lot more altitude. The recent "retracting flaps" thread touches on this too, it's a similar theme.
