Deliberately forced wing drop stalling in GFPT test
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Deliberately forced wing drop stalling in GFPT test
ATSB has published its report on the mid-air collision between a Cessna 152 and a Liberty Aerospace XL-2 near Bankstown on 18 December 2008. There was an astonishing time delay between the accident and the final report (two and a half years)
. The report stated the GFPT test required two demonstrations of the stalling sequence. Entry and recovery from a stall in the approach configuration, and entry and recovery from a stall with a wing drop. In addition, the investigation made mention of the CASA Flight Instructor Manual statement with reference to `advanced`stalling practice`, where the pilot must ensure the aircraft is recovered by at least 3000 feet agl. Presumably `advanced stalling` means stalling in a steep turn.
Two points come to mind. Modern training aircraft have benign stalling characteristics and there are stringent rules on the amount of wing drop permitted in the certification process. These aircraft include the Cessna and Piper singles of a previous era. Warbirds are different in this respect. Most current trainers waffle in a nose up attitude at the stall and are practically impossible to stall. Notwithstanding, the GFPT test requires recovery from a wing drop. However, to get these types to drop a wing requires deliberate gross mis-handling to attitudes never envisaged by the manufacturer of a non-aerobatic design. In fact, impossibly high nose attitudes and grossly exaggerated rudder inputs are needed in attempts to induce a wing drop. Even then a wing may not drop. That is how safe these aircraft are designed.
If we accept aircraft certification design that today's aircraft will not drop a wing at the point of stall, a risk of structural damage to airframe or engine is present if pilots are required to deliberately and grossly force the aircraft into exaggerated attitudes to achieve the outcome required by the GFPT.
Apply the same GFPT criteria to a Boeing 737 which has benign stalling characteristics and no pilot would remotely risk airframe damage by pulling up to 50 degrees nose high then push on full rudder to induce a wing drop. Not even in the simulator. Why then does such an antiquated and illogical requirement still exist in the GFPT test?
Deliberately forcing an aircraft into a manoeuvre beyond its design limitation is foolhardy and potentially dangerous. Whether conducted deliberately for practice or inadvertently, the aircraft should be grounded for a full structural inspection.
The second point is this. The original height limit of recovery by 3000 ft was for aerobatic manoeuvres and aimed at recovery from the looping plane or from a deliberate spin. Before first solo, students are required to demonstrate competency at recovering from a stall with minimum loss of height. Practice stalls in modern light aircraft should be easily recoverable by a competent student within 100 feet of height loss. This was even achievable in the old Tiger Moth days. Nowadays, with competency based training all the go, an instructor would not certify a student for solo stalling practice if height loss was excessive. It is therefore illogical to place 3000 ft as a minimum height at which all aircraft must be recovered from a practice stall. In any case, the time to climb above 3000 ft is expensive in terms of aircraft hire cost and utilization.
Stalling is not an aerobatic manoeuvre and the authors of the CASA Flight Instructor Manual, were living in the past when they mandated practice stalling as an aerobatic manoeuvre. On that basis a student should be certified competent in aerobatics before first solo.
CASA needs to take an enlightened attitude to light aircraft stalling characteristics and be realistic in terms of minimum height legislation.
. The report stated the GFPT test required two demonstrations of the stalling sequence. Entry and recovery from a stall in the approach configuration, and entry and recovery from a stall with a wing drop. In addition, the investigation made mention of the CASA Flight Instructor Manual statement with reference to `advanced`stalling practice`, where the pilot must ensure the aircraft is recovered by at least 3000 feet agl. Presumably `advanced stalling` means stalling in a steep turn.
Two points come to mind. Modern training aircraft have benign stalling characteristics and there are stringent rules on the amount of wing drop permitted in the certification process. These aircraft include the Cessna and Piper singles of a previous era. Warbirds are different in this respect. Most current trainers waffle in a nose up attitude at the stall and are practically impossible to stall. Notwithstanding, the GFPT test requires recovery from a wing drop. However, to get these types to drop a wing requires deliberate gross mis-handling to attitudes never envisaged by the manufacturer of a non-aerobatic design. In fact, impossibly high nose attitudes and grossly exaggerated rudder inputs are needed in attempts to induce a wing drop. Even then a wing may not drop. That is how safe these aircraft are designed.
If we accept aircraft certification design that today's aircraft will not drop a wing at the point of stall, a risk of structural damage to airframe or engine is present if pilots are required to deliberately and grossly force the aircraft into exaggerated attitudes to achieve the outcome required by the GFPT.
Apply the same GFPT criteria to a Boeing 737 which has benign stalling characteristics and no pilot would remotely risk airframe damage by pulling up to 50 degrees nose high then push on full rudder to induce a wing drop. Not even in the simulator. Why then does such an antiquated and illogical requirement still exist in the GFPT test?
Deliberately forcing an aircraft into a manoeuvre beyond its design limitation is foolhardy and potentially dangerous. Whether conducted deliberately for practice or inadvertently, the aircraft should be grounded for a full structural inspection.
The second point is this. The original height limit of recovery by 3000 ft was for aerobatic manoeuvres and aimed at recovery from the looping plane or from a deliberate spin. Before first solo, students are required to demonstrate competency at recovering from a stall with minimum loss of height. Practice stalls in modern light aircraft should be easily recoverable by a competent student within 100 feet of height loss. This was even achievable in the old Tiger Moth days. Nowadays, with competency based training all the go, an instructor would not certify a student for solo stalling practice if height loss was excessive. It is therefore illogical to place 3000 ft as a minimum height at which all aircraft must be recovered from a practice stall. In any case, the time to climb above 3000 ft is expensive in terms of aircraft hire cost and utilization.
Stalling is not an aerobatic manoeuvre and the authors of the CASA Flight Instructor Manual, were living in the past when they mandated practice stalling as an aerobatic manoeuvre. On that basis a student should be certified competent in aerobatics before first solo.
CASA needs to take an enlightened attitude to light aircraft stalling characteristics and be realistic in terms of minimum height legislation.
Last edited by Tee Emm; 12th Jul 2011 at 13:57.
Presumably `advanced stalling` means stalling in a steep turn.
Notwithstanding, the GFPT test requires recovery from a wing drop. However, to get these types to drop a wing requires deliberate gross mis-handling to attitudes never envisaged by the manufacturer of a non-aerobatic design.
Modern training aircraft have benign stalling characteristics and there are stringent rules on the amount of wing drop permitted in the certification process. These aircraft include the Cessna and Piper singles of a previous era.
"The Piper PA-38 Tomahawk, designed specifically for flight instruction, including easier demonstration of spins, was involved in 50 stall/spin accidents from 1982 through 1990, for a rate of 3.28 per 100 aircraft in the fleet. During the same period, the Cessna 150/152 had 259 stall/spin accidents, for a rate of 1.31 per 100 aircraft, and the Beech 77 suffered only four such accidents, for a rate of 1.64 per 100 aircraft."
http://www.aopa.org/asf/publications...stall_spin.pdf
Stalling is not an aerobatic manoeuvre and the authors of the CASA Flight Instructor Manual, were living in the past when they mandated practice stalling as an aerobatic manoeuvre.
It is under CAR 1988 2, "acrobatic flight" means manoeuvres intentionally performed by an aircraft involving an abrupt change in its attitude, an abnormal attitude, or an abnormal variation in speed. The FIM has the correct definition.
This definition is basically universal, the FAA have something very similar.
My understanding is that the Three thousand foot limitation allows for Two recovery mistakes on the way down.
I believe I am aware, if the club gossip is to be believed, of a stall practice in a Commander where the person undergoing endorsement got his left and right feet mixed up, among other things.
The aircraft ended in an inverted spin which consumed a great deal of altitude before the instructor made a successful recovery.
I believe I am aware, if the club gossip is to be believed, of a stall practice in a Commander where the person undergoing endorsement got his left and right feet mixed up, among other things.
The aircraft ended in an inverted spin which consumed a great deal of altitude before the instructor made a successful recovery.
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Tee Emm,
Take myself [or any experienced instructor] for a fly in a cessna or piper single and they will show you that you are on the wrong track.
I would not suggest doing it at 500'
Take myself [or any experienced instructor] for a fly in a cessna or piper single and they will show you that you are on the wrong track.
I would not suggest doing it at 500'
Take myself [or any experienced instructor] for a fly in a cessna or piper single and they will show you that you are on the wrong track.
I would not suggest doing it at 500'
I would not suggest doing it at 500'
Not something I would have walked away from if commenced at 500'.
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I would not agree with that, the rate of stall/spin accidents below 1000 ft has not really changed significantly in the last 50 years. Still responsible for a lot of accidents, and unfortunately deaths as well.
"The Piper PA-38 Tomahawk, designed specifically for flight instruction, including easier demonstration of spins, was involved in 50 stall/spin accidents from 1982 through 1990, for a rate of 3.28 per 100 aircraft in the fleet. During the same period, the Cessna 150/152 had 259 stall/spin accidents, for a rate of 1.31 per 100 aircraft, and the Beech 77 suffered only four such accidents, for a rate of 1.64 per 100 aircraft."
"The Piper PA-38 Tomahawk, designed specifically for flight instruction, including easier demonstration of spins, was involved in 50 stall/spin accidents from 1982 through 1990, for a rate of 3.28 per 100 aircraft in the fleet. During the same period, the Cessna 150/152 had 259 stall/spin accidents, for a rate of 1.31 per 100 aircraft, and the Beech 77 suffered only four such accidents, for a rate of 1.64 per 100 aircraft."
Modern training aircraft have benign stalling characteristics and there are stringent rules on the amount of wing drop permitted in the certification process. These aircraft include the Cessna and Piper singles of a previous era.
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I would not agree with that, the rate of stall/spin accidents below 1000 ft has not really changed significantly in the last 50 years. Still responsible for a lot of accidents, and unfortunately deaths as well
I would suggest that whiilst 3000 ft seems over cautios altitude for ALL stalling, it does provide a level of comfort to the ab initio student, to whom this is very unfamiliar and stressful, as well as re-inforcing to more competent pilots that this is a maneuvre that is outside 'normal operating' procedures in general and should be treated respectfully, that it does also allow sufficient altitude for a stuffed up recovery, though a good instructor should recognize and prevent such a thing happening.
My understanding is that the Three thousand foot limitation allows for Two recovery mistakes on the way down.
As an instructor I ecercise a degree of discretion regarding stalling practice altitudes, especially as the training level advances, CPL, Aeros, spinning
During Ag training stalling in a loaded aircraft is expected to be able to be demonstrated at 200' with a recovery by 100'. this is a highly incentivated training procedure, but certainly not for ab-initio or 'average' pilots.
HD
Replies seem to indicate an unfounded fear of stall practice as a training sequence. There are still pilots around who were fortunate to have flown wartime types where certification rules to make aircraft safer had not been introduced. Some of these could be quite unsettling in stall behaviour (the Australian Wirraway was just one example) and unintentional spins could occur if stall recovery was mis-handled.
For this reason the original 3000 ft height limit for recovery from aerobatics was introduced into civilian aero clubs post war because these aircraft were still around. Times have changed since 1945 and apart from the occasional poorly maintained training aircraft the certification process has steadily improved making stalling a non-event. All current modern training aircraft are so reluctant to stall it takes more handling skill to force the aircraft to stall than it takes to recover. The tail wagging the dog, so to speak.
The current `rules` on minimum heights for stall practice coupled with a CASA directed requirement to force a wing drop by unnatural means if necessary, are archaic and rather quaint. A blast from the past?
In contrast, the gliding fraternity are not so hidebound and stall practice is frequently done at circuit height. Keeping in mind that a glider has no engine power to help recovery so the nose must be lowered to gain safe flying speed. Even then height loss is barely 100 feet.
For this reason the original 3000 ft height limit for recovery from aerobatics was introduced into civilian aero clubs post war because these aircraft were still around. Times have changed since 1945 and apart from the occasional poorly maintained training aircraft the certification process has steadily improved making stalling a non-event. All current modern training aircraft are so reluctant to stall it takes more handling skill to force the aircraft to stall than it takes to recover. The tail wagging the dog, so to speak.
The current `rules` on minimum heights for stall practice coupled with a CASA directed requirement to force a wing drop by unnatural means if necessary, are archaic and rather quaint. A blast from the past?
In contrast, the gliding fraternity are not so hidebound and stall practice is frequently done at circuit height. Keeping in mind that a glider has no engine power to help recovery so the nose must be lowered to gain safe flying speed. Even then height loss is barely 100 feet.
I don't think I have ever lost more than 500 feet in a stall from the moment I first tried it. But would I do stalling at 1,000ft AGL? I'd rather have a little bit more distance to play with, most places you can climb to 3,000ft while getting to the training area so it doesn't really take much extra time. Nowadays I know I can recover with minimal height loss but I still wouldn't do them any lower than I had to.
Ag training is a different kettle of fish as we all know but general training, why not give yourself some wiggle room?
Ag training is a different kettle of fish as we all know but general training, why not give yourself some wiggle room?
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stalls in a large jet are a little bit different to a single engine light aircraft although the principles are the same different power/weight ratio's, performance and stall characteristics....
Been struggling to figure the purpose of this thread.
What is a "modern training aircraft"? I still see a lot of C150/152 and PA28 around in a training role, and even the occassional PA38.
The 150/152 can get your attention stalled with 20o flap and 1800 rpm, and the Traumahawk can get downright interesting when stalled in a similar config. I used to instruct in one that would rapidly roll onto its back!
Must confess to doing lots of stalls at 1000' - depends on the aeroplane and your familiarity with it, however, I know a few (incuding myself) who would not be here had they not started out above 3000' on at least one occassion.
The V-tail can get a bit excited when stalled in the approach config but all-in-all is a pussy cat! However, some idiot decided that the A36 needed to be tamed and put those stupid looking wedges on the leading edges of the wing - and spoiled the look of a beautiful aeroplane.
Dr
Modern training aircraft have benign stalling characteristics and there are stringent rules on the amount of wing drop permitted in the certification process.
The 150/152 can get your attention stalled with 20o flap and 1800 rpm, and the Traumahawk can get downright interesting when stalled in a similar config. I used to instruct in one that would rapidly roll onto its back!
Must confess to doing lots of stalls at 1000' - depends on the aeroplane and your familiarity with it, however, I know a few (incuding myself) who would not be here had they not started out above 3000' on at least one occassion.
The V-tail can get a bit excited when stalled in the approach config but all-in-all is a pussy cat! However, some idiot decided that the A36 needed to be tamed and put those stupid looking wedges on the leading edges of the wing - and spoiled the look of a beautiful aeroplane.
Dr
Been struggling to figure the purpose of this thread.
Secondly, the poster is saying that to force an aircraft into a wing drop in order to meet a GFPT test requirement in an aircraft that is designed NOT to drop wings, is illogical (read crazy). He should have added that the design certification of recent types (last 25 years) means the ailerons are effective below stalling speed and have the capability of levelling the wings during stall recovery.
Despite this, there is no shortage of flying instructors who were taught on their instructors course to pick up a dropped wing solely by skidding the aircraft using rudder until the wings are level - even though this could lead to a spin in the opposite direction to the first dropped wing. And these instructors teach their new students the same thing and the myth
propagates. All this leads to students and their instructors jumping at shadows whenever the subject of stalling practice comes up
I hope this helps your `struggles`, Fork Tail
Planes are designed not to have an engine failure, should we not practice forced landings too?
As said above a 150, in approach config, handled a bit roughly can drop a wing. And if it's on approach you damn well want to have recovered from it before in a training environment.
And the 3,000ft? As I said above, why go lower for initial training at least? I don't think I ever lost more than 500 ft (or even 250ft) and I don't think many people do, but there are enough stories.
As said above a 150, in approach config, handled a bit roughly can drop a wing. And if it's on approach you damn well want to have recovered from it before in a training environment.
And the 3,000ft? As I said above, why go lower for initial training at least? I don't think I ever lost more than 500 ft (or even 250ft) and I don't think many people do, but there are enough stories.
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Centaurus correctly mentions that the glider boys will practice stall training at circuit height. I personally did my spin training with Mike Valentine (dec) not above 1200 agl....man does the earth look huge!
To a glider pilot stall/spin training is more serious than learning how to thermal. When you are sharing a thermal with other gliders, your concentration is largely outside the cockpit, esp if you have beeping vario's (vario=hypersensitive VSI). Being that nature you are not watching the ASI, and in a bumpy thermal you are also dealing with a constantly changing nose attitude. Gliders are not subject to the same regs as say a PA28, so their likelihood of departing into a spin is increased. Having flown gliders of greater than 25 metres span, their docile nature is rudely interupted by their readiness to spin, so you have to be on the ball. Glider pilots are trained to a level, where they recognise the stall without aid of instruments or horizon and immediatley manage the wing drop with rudder, and continue around the thermal turn as if nothing ever happened.
The argument that a PA28 is designed to be benign and seriously forgiving (which it is) and that the regs/testing should reflect that, although once a truth, is now a falacy. You need to look at what people are training in now. We have VH registered ultralights (different design regs) and even people doing the bulk of their training in RAA registered and then swapping to a GA ticket. We are furtunate enough that many of the people teaching in RAA are also qualified to teach in GA. (and no i am NOT saying RAA trained instructors are less qualified)
The 3000' limitation. Hmm I have no problem with that, as the reg governing that is designed to cover multiple types and give you space for them all. Who said training should be risky?
So what is Advanced stalling?
Some say that it is in the approach or climb configuration.
To me it is ensuring that the student understands the practical side of the aerodynamics of managing any wing drop with rudder rather than aileron. A 161 warrior will forgive you, but a Grumman Trainer/cheetah/tiger won't. It is also about ensuring the student has the skills to move onto more complex types with not so benign handling.
As for forcing a type to drop a wing in the the test...PHOOEY!..... even a warrior will waddle about the lateral axis in a stall......theres your wing drop, get the student to manage it with rudder rather than aileron and you have advanced stalling and he/she is ready to move onto something less forgiving.
Cheers
Jas
(PS I took this whole conversation was based on the comments of what the student is doing the test in, when the regulatory body needs to consider what they might fly next)
To a glider pilot stall/spin training is more serious than learning how to thermal. When you are sharing a thermal with other gliders, your concentration is largely outside the cockpit, esp if you have beeping vario's (vario=hypersensitive VSI). Being that nature you are not watching the ASI, and in a bumpy thermal you are also dealing with a constantly changing nose attitude. Gliders are not subject to the same regs as say a PA28, so their likelihood of departing into a spin is increased. Having flown gliders of greater than 25 metres span, their docile nature is rudely interupted by their readiness to spin, so you have to be on the ball. Glider pilots are trained to a level, where they recognise the stall without aid of instruments or horizon and immediatley manage the wing drop with rudder, and continue around the thermal turn as if nothing ever happened.
The argument that a PA28 is designed to be benign and seriously forgiving (which it is) and that the regs/testing should reflect that, although once a truth, is now a falacy. You need to look at what people are training in now. We have VH registered ultralights (different design regs) and even people doing the bulk of their training in RAA registered and then swapping to a GA ticket. We are furtunate enough that many of the people teaching in RAA are also qualified to teach in GA. (and no i am NOT saying RAA trained instructors are less qualified)
The 3000' limitation. Hmm I have no problem with that, as the reg governing that is designed to cover multiple types and give you space for them all. Who said training should be risky?
So what is Advanced stalling?
Some say that it is in the approach or climb configuration.
To me it is ensuring that the student understands the practical side of the aerodynamics of managing any wing drop with rudder rather than aileron. A 161 warrior will forgive you, but a Grumman Trainer/cheetah/tiger won't. It is also about ensuring the student has the skills to move onto more complex types with not so benign handling.
As for forcing a type to drop a wing in the the test...PHOOEY!..... even a warrior will waddle about the lateral axis in a stall......theres your wing drop, get the student to manage it with rudder rather than aileron and you have advanced stalling and he/she is ready to move onto something less forgiving.
Cheers
Jas
(PS I took this whole conversation was based on the comments of what the student is doing the test in, when the regulatory body needs to consider what they might fly next)
I agree with a minimum height for stalling practice in any aircraft, recover by 3000ft AGL, why not, especially with students practicing for the first time. I know of at least two occasions where a student has locked up on the controls preventing recovery and the instructor has regained control with the loss of over 1000ft.
Train in a Grob and you'll get a healthy respect for low speed flight. Very good at teaching rudder control with power changes and near the stall. Poor ruder use at low speed = inverted flight.
A PA28 is very docile, until you load it full aft CoG or near it and mishandle it near the stall. When it lets go it will rapidly roll on its back, treat any aircraft with respect at low speed.
Airliners are no different near the stall, throw in some ice and even the best designed aircraft can do anything it wishes. The ATSB has some interesting reading regarding airliners stalling and recovery techniques. There have been some very close calls. Swept wings and t-tails etc make things more complicated near the stall but still the same applies, dont go there if you dont have to.
Why practice any abnormal procedure at low altitude that does'nt require you to be there, even a normal high angle of bank turn has risks let alone combining it with a stall.
I learned to fly on Grobs...they're spin capable (with the kit fitted). If you kick in too much rudder correction with a wing drop situation, it'll flick the other way. I learned one hell of a lot flying those.
A 161 warrior will forgive you, but a Grumman Trainer/cheetah/tiger won't.
Airliners are no different near the stall, throw in some ice and even the best designed aircraft can do anything it wishes. The ATSB has some interesting reading regarding airliners stalling and recovery techniques. There have been some very close calls. Swept wings and t-tails etc make things more complicated near the stall but still the same applies, dont go there if you dont have to.
Why practice any abnormal procedure at low altitude that does'nt require you to be there, even a normal high angle of bank turn has risks let alone combining it with a stall.
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You must teach a student how to recover from a stall and incipient spin. These situations happen when you least expect it, turning final and lapses of concentration.
I always induced a wing drop on the GFPT, PPL,CPL and BFR. Students must be proficient at recognising and recovering from both situations. The stall/spin situation is a killer.
I always induced a wing drop on the GFPT, PPL,CPL and BFR. Students must be proficient at recognising and recovering from both situations. The stall/spin situation is a killer.
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practical side of the aerodynamics of managing any wing drop with rudder rather than aileron.
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Not picking up a wing with rudder but to stop further yaw in the direction of the lowered wing. The ailerons should be neutral until control is regained, then level the wings.
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Surely one of the common precursors to "loss of control" is disorientation. In which case it is unlikely that a disorientated pilot (eg in IMC, low level downwind turn etc) will be able to recognise and recover from a stall if they are disorientated enough to get into the stall in the first place.
Yet in the briefng I see lots of nice colourful pictures with wiggley lines and no explanation of why you would end up there/prevent ending up there in the first place. Then in the training sequence, some instructors will suddenly whack in all sorts of control inputs such as the OP has mentioned leaving some students wondering if the aeroplane has a mind of its own, because otherwise how could this situation arise on a nice day with a good horizon?
I you read the syllabus carefully there is no requirement for wild control inputs in order for the student to be found competent in stall recognition and recovery,
Yet in the briefng I see lots of nice colourful pictures with wiggley lines and no explanation of why you would end up there/prevent ending up there in the first place. Then in the training sequence, some instructors will suddenly whack in all sorts of control inputs such as the OP has mentioned leaving some students wondering if the aeroplane has a mind of its own, because otherwise how could this situation arise on a nice day with a good horizon?
I you read the syllabus carefully there is no requirement for wild control inputs in order for the student to be found competent in stall recognition and recovery,