Wing drop recovery at the stall - killing an old myth.
Aircraft spin differently depending on aerodynamic characteristics, B/A ratios etc. so there's no real generic recovery that'll work for everything.
Those that are approved for spinning should have procedures in the flight manual that work for the type.
I have flown types that call for progressive introduction of forward stick until the spin stops, among other things, so it's not necessarily a dangerous thing, just one that may or may not be called for if the type requires it.
In some (for example, the PC-9), there's a requirement that they be spun in maintenance test flying and must recover both hands on and hands off in a prescribed number of turns (different for each type of recovery).
It's fairly pointless having a standard spin recovery that you use for every type if it's not going to work in every case, so familiarity with the type must be the go.
However, the general principles of throttle idle, identify direction of spin, full opposite rudder, control column centrally forward until spin stops, centralise and recover from the dive wouldn't be too bad for an upright spin. In some types they also advocate in-spin aileron if it's not recovering, but as I said, it's type specific.
Edit: Wiz, points noted about the Pitts, I haven't flown it, but on the other hand, the control column centrally forward thing is definitely called for in some types.
Those that are approved for spinning should have procedures in the flight manual that work for the type.
I have flown types that call for progressive introduction of forward stick until the spin stops, among other things, so it's not necessarily a dangerous thing, just one that may or may not be called for if the type requires it.
In some (for example, the PC-9), there's a requirement that they be spun in maintenance test flying and must recover both hands on and hands off in a prescribed number of turns (different for each type of recovery).
It's fairly pointless having a standard spin recovery that you use for every type if it's not going to work in every case, so familiarity with the type must be the go.
However, the general principles of throttle idle, identify direction of spin, full opposite rudder, control column centrally forward until spin stops, centralise and recover from the dive wouldn't be too bad for an upright spin. In some types they also advocate in-spin aileron if it's not recovering, but as I said, it's type specific.
Edit: Wiz, points noted about the Pitts, I haven't flown it, but on the other hand, the control column centrally forward thing is definitely called for in some types.
Hi Arm,.
Agree with all you say. This Gentleman has got his spin recovery because "Someone said"- What the maker puts in the book is what's most important.
The part that REALLY got my attention with what M082 posted was that he stated FULL forward stick THEN rudder- not progressive and not stopping the rotation first. I've never heard of ANY type where you put the stick forward before stopping the rotation. That IS the recipe for a cross over to inverted spinning.
Agree with all you say. This Gentleman has got his spin recovery because "Someone said"- What the maker puts in the book is what's most important.
The part that REALLY got my attention with what M082 posted was that he stated FULL forward stick THEN rudder- not progressive and not stopping the rotation first. I've never heard of ANY type where you put the stick forward before stopping the rotation. That IS the recipe for a cross over to inverted spinning.
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On a side note, has anyone had a piper archer roll on it's back, this happened on my PPL pre-test over Bribie Island, the Archer rolled right around, I recovered and we tried again with the exact same conditions, this time just the usual slip into an incipent spin, this was with flap and 1800 rpm? Strange 
Some excellent notes on spinning at these websites:
flightlab.net - link to 654k pdf file
http://www.apstraining.com/newsletterlist.htm
Just a few comments to add to the discussion:
- totally agree with Arm Out the Window
- didn't think that M082 posted "FULL forward stick THEN rudder" - he used the word "and". Generally, tails like the CT-4 don't suffer from the horizontal tail "blanketing" the fin. I don't have an AFM for the CT-4, Zlin 242 or Chipmunk handy but I'll take a punt that at least one doesn't specify the order of control application and they certainly do require full forward stick (the CT-4 from its flat spin mode)
- having said that, remembering PARE and doing it in that order will generally keep you out of trouble - regardless, whatever is in the AFM takes precedence over what I state
- full forward stick in a Pitts, while in a developed upright spin, will produce a steep accelerated spin. If power and/or aileron is used to flatten it, subsequently moving the stick forward aggravates the flat spin
- Beggs-Mueller technique doesn't work for the Zlin, for example
- Bill Finagin promotes simply centralizing the controls in the Pitts as an alternative to Beggs-Mueller as an emergency technique (in a limited number of types) - on his last visit he demonstrated this to a few locals - including flat upright and inverted spins
- some common GA types recover readily from a fully developed spin with PARE - the elevator bit only requiring relaxation of back pressure - however leaving power on or aileron in the "wrong" position will significantly delay recoveries (often flattening the spin)
flightlab.net - link to 654k pdf file
http://www.apstraining.com/newsletterlist.htm
Just a few comments to add to the discussion:
- totally agree with Arm Out the Window
- didn't think that M082 posted "FULL forward stick THEN rudder" - he used the word "and". Generally, tails like the CT-4 don't suffer from the horizontal tail "blanketing" the fin. I don't have an AFM for the CT-4, Zlin 242 or Chipmunk handy but I'll take a punt that at least one doesn't specify the order of control application and they certainly do require full forward stick (the CT-4 from its flat spin mode)
- having said that, remembering PARE and doing it in that order will generally keep you out of trouble - regardless, whatever is in the AFM takes precedence over what I state
- full forward stick in a Pitts, while in a developed upright spin, will produce a steep accelerated spin. If power and/or aileron is used to flatten it, subsequently moving the stick forward aggravates the flat spin
- Beggs-Mueller technique doesn't work for the Zlin, for example
- Bill Finagin promotes simply centralizing the controls in the Pitts as an alternative to Beggs-Mueller as an emergency technique (in a limited number of types) - on his last visit he demonstrated this to a few locals - including flat upright and inverted spins
- some common GA types recover readily from a fully developed spin with PARE - the elevator bit only requiring relaxation of back pressure - however leaving power on or aileron in the "wrong" position will significantly delay recoveries (often flattening the spin)
Yo Pilks!!!!
Obviously what we should have done was just answered the original questions with "Ask Dave"!!
Agreed M082 said "And" and that will work on some types. The fact that he mentioned elevator first (and didn't talk about power or aileron) rang alarm bells.
What are you aerobatting these days?
Obviously what we should have done was just answered the original questions with "Ask Dave"!!
Agreed M082 said "And" and that will work on some types. The fact that he mentioned elevator first (and didn't talk about power or aileron) rang alarm bells.
What are you aerobatting these days?
Not being in Aus, don't normally look at this forum. But the title of the thread caught my eye. I find it hard to believe that people are still teaching the 'picking up the wing with rudder' rubbish. It had largely been stamped out in the UK thanks to a vigourous campaign by the UK CAA. And if anyone is in doubt, perhaps they should have a look at the CASA Flight Instructor Manual, free to download and IMHO, one of the best instructor manuals ever written. I quote from Section 9, Stalling:
'Emphasize that if the wing drops, rudder is to be used to prevent yaw into the direction of the lowered wing. The wing is raised with aileron when it is unstalled'.
That should seal the fate of that technique. It may work in some aircraft, but with others - large inputs of yaw when the wing is stalled will cause a spin.
And as for spin recovery, know the particular technique for your aircraft type. If it's cleared for spinning the recovery should be the POH. recovery techniques are not the same for all types. Of the types I have instructed on, one needed a two second pause between application of rudder and moving the control column forward enough to unstall the wings (Chipmunk), another needed no pause and full forward control column movement (Bulldog). I was flying both at the same time once, knowing your aircraft's technique was essential.
'Emphasize that if the wing drops, rudder is to be used to prevent yaw into the direction of the lowered wing. The wing is raised with aileron when it is unstalled'.
That should seal the fate of that technique. It may work in some aircraft, but with others - large inputs of yaw when the wing is stalled will cause a spin.
And as for spin recovery, know the particular technique for your aircraft type. If it's cleared for spinning the recovery should be the POH. recovery techniques are not the same for all types. Of the types I have instructed on, one needed a two second pause between application of rudder and moving the control column forward enough to unstall the wings (Chipmunk), another needed no pause and full forward control column movement (Bulldog). I was flying both at the same time once, knowing your aircraft's technique was essential.
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I agree to a point. The application of rudder at the point of stall needs to be quite violent in most GA aircraft to induce a stall. That is the way they are designed. I still think an application of rudder at the point of stall in the opposite direction to the wing drop will always create a neater recovery to straight and level with minimum height loss. To disregard a primary flight control surface as a possible method of recovery is a little rash if you ask me. The flight instructors manual will obviously cater for the incorrect input and or too much rudder input by a student. In this respect it is duely conservative. I think it is a little foolish however to call a technique that has been taught for decades,"rubbish". The wording I think is a safe guard for CASA rather than a "set in stone" teaching method. If a student goes out practices stalls and spins in, who is going to know what he actually did anyway! I'm still a stick AND rudder man.
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"787 Captain,
If you go and try an Aerobatic manoeuvre/recovery based on what someone says on the internet (and that goes for what I've just said!!) you need your head read. Go and talk to an experienced, reputable Aerobatic instructor (Phil Unicomb at Maitland springs to mind), DO NOT try what M082 has advocated- I've picked bits of Aeroplane out of a tree as a result of that technique!!"
Yeah, I wouldn't take what's said on the internet as the right way. What he said made sense though when I thought about the time I was in a pretty flat spin. It often seems obvious when you're in a particular situation what to do, but having not done heaps of aerobatics like some other people on here I'll probably be sticking with what I was taught and not really trying other people's techniques much.
Aircraft:
"Now I am really curious. What is this "rotation"? Is it rotation, as in "spin rotation" or rotation about the longitudinal axis, as in roll? Or is it rotation about both the longitudinal and normal axes (i.e. roll and yaw)?
As best I can tell, your usage of "rotation" refers initially to the roll of the wing drop but then also refers to the spin rotation that occurs later.
Aviation has terms such as "roll", "pitch" and "yaw" so that one can describe exactly the motion of an aircraft. Your insistence on using the term "rotation" by itself is confusing."
I know very well what terms aviation uses. Even if I have used the term rotation wrongly at 12 o'clock at night I'm sure you can figure out what I meant. But I thought it was clear enough. I wouldn't have personally called a wingdrop 'roll' given that you are stalled, but even if it is roll you know what I mean.
If you go and try an Aerobatic manoeuvre/recovery based on what someone says on the internet (and that goes for what I've just said!!) you need your head read. Go and talk to an experienced, reputable Aerobatic instructor (Phil Unicomb at Maitland springs to mind), DO NOT try what M082 has advocated- I've picked bits of Aeroplane out of a tree as a result of that technique!!"
Yeah, I wouldn't take what's said on the internet as the right way. What he said made sense though when I thought about the time I was in a pretty flat spin. It often seems obvious when you're in a particular situation what to do, but having not done heaps of aerobatics like some other people on here I'll probably be sticking with what I was taught and not really trying other people's techniques much.
Aircraft:
"Now I am really curious. What is this "rotation"? Is it rotation, as in "spin rotation" or rotation about the longitudinal axis, as in roll? Or is it rotation about both the longitudinal and normal axes (i.e. roll and yaw)?
As best I can tell, your usage of "rotation" refers initially to the roll of the wing drop but then also refers to the spin rotation that occurs later.
Aviation has terms such as "roll", "pitch" and "yaw" so that one can describe exactly the motion of an aircraft. Your insistence on using the term "rotation" by itself is confusing."
I know very well what terms aviation uses. Even if I have used the term rotation wrongly at 12 o'clock at night I'm sure you can figure out what I meant. But I thought it was clear enough. I wouldn't have personally called a wingdrop 'roll' given that you are stalled, but even if it is roll you know what I mean.
Of historical general interest from my very battered copy of Pilots Notes for Mustang.
"Stalling - When no fuel is carried in the fuselage tank, slight tail buffeting occurs about 2 or 3 knots above the stall, at which one wing drops gently. With fuselage tank full or half full, there is no buffeting to give warning of the approaching stall, but a series of stick reversals occurs just above stalling speed; at the stall the right wing drops sharply, and unless immediate recovery action is taken, a spin may develop. The control column must be moved firmly forward for recovery.
The aircraft sinks rapidly as stalling speed is approached. If the control column is held back at the stall, a wing will drop very rapidly and the aircraft will become inverted.
Spinning - Practice spins are not to be started below 12,000 ft and the engine is to be throttled back before starting the spin. recovery action is to be taken after not more than two turns. The average height loss in turns and in the recovery is about 3000-3500 ft.
The nose falls steeply as the spin is entered. The spin tends to be extremely uneven, slowing down almost to a stop with the nose above or below the horizon and speeding up as the nose falls in each turn. Unless full rudder is applied in the direction of the spin when it is developing, the aircraft tends to recover unassisted by the pilot. If normal recovery action is taken after two turns have been completed, the aircraft recovers immediately. If recovery action is taken after four turns, the rate of rotation at first increases for about 3-4 turns and the aircraft then recovers.
Power-on spins should never be intentionally performed. The nose remains 10-20 degrees above the horizon and normal recovery action has no effect until,the throttle is closed. As many as five or six turns may be made after recovery action and 9000-10,000 ft is lost. If however the spin should remain flat on throttling back and taking normal recovery action, the aircraft should be rocked fore and aft by full movement of the control column, opening up the engine as the stick is pulled back and throttling back as it is pushed forward. A speed of at least 156 knots IAS should be attained before easing out of the dive."
I recall climbing to 15,000 ft before before performing my first spin in a Mustang and certainly the advice about the uneven nature of the spin as described above, was correct. Mind you we wore a parachute if something went wrong, which was a great comfort.
"Stalling - When no fuel is carried in the fuselage tank, slight tail buffeting occurs about 2 or 3 knots above the stall, at which one wing drops gently. With fuselage tank full or half full, there is no buffeting to give warning of the approaching stall, but a series of stick reversals occurs just above stalling speed; at the stall the right wing drops sharply, and unless immediate recovery action is taken, a spin may develop. The control column must be moved firmly forward for recovery.
The aircraft sinks rapidly as stalling speed is approached. If the control column is held back at the stall, a wing will drop very rapidly and the aircraft will become inverted.
Spinning - Practice spins are not to be started below 12,000 ft and the engine is to be throttled back before starting the spin. recovery action is to be taken after not more than two turns. The average height loss in turns and in the recovery is about 3000-3500 ft.
The nose falls steeply as the spin is entered. The spin tends to be extremely uneven, slowing down almost to a stop with the nose above or below the horizon and speeding up as the nose falls in each turn. Unless full rudder is applied in the direction of the spin when it is developing, the aircraft tends to recover unassisted by the pilot. If normal recovery action is taken after two turns have been completed, the aircraft recovers immediately. If recovery action is taken after four turns, the rate of rotation at first increases for about 3-4 turns and the aircraft then recovers.
Power-on spins should never be intentionally performed. The nose remains 10-20 degrees above the horizon and normal recovery action has no effect until,the throttle is closed. As many as five or six turns may be made after recovery action and 9000-10,000 ft is lost. If however the spin should remain flat on throttling back and taking normal recovery action, the aircraft should be rocked fore and aft by full movement of the control column, opening up the engine as the stick is pulled back and throttling back as it is pushed forward. A speed of at least 156 knots IAS should be attained before easing out of the dive."
I recall climbing to 15,000 ft before before performing my first spin in a Mustang and certainly the advice about the uneven nature of the spin as described above, was correct. Mind you we wore a parachute if something went wrong, which was a great comfort.
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The Very Rare Inadvertent Spin Animal
Of course, although we practise spinning until we become blase about it, few instructors address the occasions when you might enter an inadvertent spin (or why). In many years of instructing on glider, ab initio GA through advanced jet I have never seen a student ever come close to inadvertently entering a spin in base to finals turn (or anywhere else for that matter). The spin that you are most likely going to enter unintentionally is in heavy icing - and with the autopilot driving - and masking the incipient condition. The other case is restricted to TU154 pilots who go outside the envelope.
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The Caravan's loss of control in icing conditions problem may be similar to that of twin-engine turbo-props in severe icing conditions. Because the Left and Right engines' propellers both rotate in the same direction, the icing buildup port and starboard side of the wings, fuselage and empennage is very asymmetric. So eventually one wing will stall first. In the SF340 and ATR72 for instance, it's always the RH (stbd) wing that stalls first. The pilot's instinctive reaction of trying to pick up that icing-stalled wing with aileron (only) stalls that side further (and for the same reason tends to unstall the port wing). The result is a rapid autorotative roll into that stalled wing, exacerbated by the pilot's instinctive response of continuing to use aileron (eventually up to full) to pick up that dropping wing. The scenario buildup has most often been disguised by the autopilot soaking up lateral loads and auto-trim disguising the loss of airspeed down to a much higher stall speed that's due to the drag and weight of accumulating ice.
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To a lesser extent there will be a similar airborne problem with the single-engined Caravan's PT-6 propeller leading to an asymmetric build-up of ice spanwise on the Caravan's wing (think of the prop's helical flow aft around the fuselage and how that rapid build-up of icing is being rearranged differently above and below (as well as spanwise on) the port and starboard wings. Because of the nature of the problem in turbo-props (and recips), the addition of wing leading-edge fences, L.E. droops, extension of boots, boot cycling rates or aileron fences won't achieve much at all. The NTSB's conclusions on the Roselawn ATR72 accident were flawed; it wasn't a problem with aileron effectiveness or ridges of ice forward of the aileron blanking the aileron or reversing its effect. It was a characteristic of asymmetric icing that comes courtesy of both props rotating in the same direction; i.e. one wing stalling first and the rapid roll (into a deadly spiral) consequence of using aileron to "pick-up" a stalled and dropping wing. The same scenario likely applied in the ATR72 freighter crash in the Taiwan Straits and the EMB120 at Monroe Michigan. There had been a similar six previous EMB-120 accidents in icing conditions.
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For turboprops, the only solution to spinning out of severe icing in rain-ice, freezing rain (that which the FAA likes to call SLD or Supercooled Large Droplets) is a different method of de-icing. Meanwhile pilots are expected to exit severe icing rapidly and not to use the autopilot in icing conditions. And of course the other complication is that nobody but nobody ever goes out and intentionally spins a light, medium or heavy twin. Speaking as somebody who has, I can tell you now that the B/A ratio effect is convincing enough to allow you do it but once, on purpose.
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The Caravan's loss of control in icing conditions problem may be similar to that of twin-engine turbo-props in severe icing conditions. Because the Left and Right engines' propellers both rotate in the same direction, the icing buildup port and starboard side of the wings, fuselage and empennage is very asymmetric. So eventually one wing will stall first. In the SF340 and ATR72 for instance, it's always the RH (stbd) wing that stalls first. The pilot's instinctive reaction of trying to pick up that icing-stalled wing with aileron (only) stalls that side further (and for the same reason tends to unstall the port wing). The result is a rapid autorotative roll into that stalled wing, exacerbated by the pilot's instinctive response of continuing to use aileron (eventually up to full) to pick up that dropping wing. The scenario buildup has most often been disguised by the autopilot soaking up lateral loads and auto-trim disguising the loss of airspeed down to a much higher stall speed that's due to the drag and weight of accumulating ice.
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To a lesser extent there will be a similar airborne problem with the single-engined Caravan's PT-6 propeller leading to an asymmetric build-up of ice spanwise on the Caravan's wing (think of the prop's helical flow aft around the fuselage and how that rapid build-up of icing is being rearranged differently above and below (as well as spanwise on) the port and starboard wings. Because of the nature of the problem in turbo-props (and recips), the addition of wing leading-edge fences, L.E. droops, extension of boots, boot cycling rates or aileron fences won't achieve much at all. The NTSB's conclusions on the Roselawn ATR72 accident were flawed; it wasn't a problem with aileron effectiveness or ridges of ice forward of the aileron blanking the aileron or reversing its effect. It was a characteristic of asymmetric icing that comes courtesy of both props rotating in the same direction; i.e. one wing stalling first and the rapid roll (into a deadly spiral) consequence of using aileron to "pick-up" a stalled and dropping wing. The same scenario likely applied in the ATR72 freighter crash in the Taiwan Straits and the EMB120 at Monroe Michigan. There had been a similar six previous EMB-120 accidents in icing conditions.
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For turboprops, the only solution to spinning out of severe icing in rain-ice, freezing rain (that which the FAA likes to call SLD or Supercooled Large Droplets) is a different method of de-icing. Meanwhile pilots are expected to exit severe icing rapidly and not to use the autopilot in icing conditions. And of course the other complication is that nobody but nobody ever goes out and intentionally spins a light, medium or heavy twin. Speaking as somebody who has, I can tell you now that the B/A ratio effect is convincing enough to allow you do it but once, on purpose.
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Thank you for your post UNCTUOUS.
What has caught my attention now is that in the Pilot's Operating Handbook for one of the aircraft I fly, is says for stall recovery to lower the nose and apply full power simultaneously, and to then use the rudder to maintain lateral control. If, for example, you get a wingdrop to the left, wouldn't the effect of torque due to the application of power cause the left wing to get lower and make the situation worse? Or would lowering the nose and applying power get you out of the stall and then you can level the aircraft?
What has caught my attention now is that in the Pilot's Operating Handbook for one of the aircraft I fly, is says for stall recovery to lower the nose and apply full power simultaneously, and to then use the rudder to maintain lateral control. If, for example, you get a wingdrop to the left, wouldn't the effect of torque due to the application of power cause the left wing to get lower and make the situation worse? Or would lowering the nose and applying power get you out of the stall and then you can level the aircraft?
One C152 dropped the left wing violently at point of stall when clean. Was even worse with flaps and 1200rpm. Height loss was 500 ft and by the time recovery was effected the aircraft had turned through almost 180 degrees. It had been like this for a long time but had been accepted by instructors who flew it, as normal. A wing drop like this near the ground would have been difficult to handle - particularly for new pilots. Worse still they would not have been warned of it except by word of mouth, because no one snagged it.
CASA airworthiness were concerned and arranged for it to be flight tested by an FOI. The owner quickly responded by re-rigging the wings and after that it flew OK. Moral of that story is that if you have a rogue aircraft that stalls unconventionally, write up the defect in the mintenance release and ensure the fault is rectified. It could save a life.
CASA airworthiness were concerned and arranged for it to be flight tested by an FOI. The owner quickly responded by re-rigging the wings and after that it flew OK. Moral of that story is that if you have a rogue aircraft that stalls unconventionally, write up the defect in the mintenance release and ensure the fault is rectified. It could save a life.
