Power on Stalls
Thread Starter
Join Date: Mar 2001
Location: Toronto, Ont, Canada
Posts: 223
Likes: 0
Received 0 Likes
on
0 Posts
Power on Stalls
I was reading someone's pilot training blog (based in U.S.) (ya I need to get a life), and they were describing their experience with power-on stalls.
The procedure being taught was to apply full power, while climbing at
Vx, then apply backpressure until the plane stalled.
I'm wondering if that is the standard / FAA / flight school s.o.p. ?
Wha is the technique used in the U.K .. or other countries?
In the U.S. is there a set syllabus that flight schools / instructors have to
follow? ... or is just a matter of covering what is required on the
flight test? (is this technique tested on the flight test?)
I'm in Canada, and in my flight training, power-on stalls were performed
at ~1700-1800 r.p.m. with 10deg flaps (C172).
While I can see some benefit to the "full power Vx" stall, as it
apparently is aimed at training how to recover from a stall at takeoff or from a go around, it also seems that it might be verging on the "whip stall" manouver (that I've never really seen a good definition for btw), which are
prohibited in the C172 p.o.h. It would also seem to be, a pretty violent
stall (I've personally never tried one with that technique).
comments ?
Mike
The procedure being taught was to apply full power, while climbing at
Vx, then apply backpressure until the plane stalled.
I'm wondering if that is the standard / FAA / flight school s.o.p. ?
Wha is the technique used in the U.K .. or other countries?
In the U.S. is there a set syllabus that flight schools / instructors have to
follow? ... or is just a matter of covering what is required on the
flight test? (is this technique tested on the flight test?)
I'm in Canada, and in my flight training, power-on stalls were performed
at ~1700-1800 r.p.m. with 10deg flaps (C172).
While I can see some benefit to the "full power Vx" stall, as it
apparently is aimed at training how to recover from a stall at takeoff or from a go around, it also seems that it might be verging on the "whip stall" manouver (that I've never really seen a good definition for btw), which are
prohibited in the C172 p.o.h. It would also seem to be, a pretty violent
stall (I've personally never tried one with that technique).
comments ?
Mike
That is totally unnecessary dangerous flying. A power-on stall only needs to be done in the approach configuration with landing flap down and a trickle of power between 1200 and 1500 rpm. Recovery action is normal. Sounds like some idiot is out to kill you!!
There are 4 stall configurations on the current LST/LPC form: idle/clean, final turn, approach, and departure. The first is held until it develops and the examiner calls for recovery, the others are recovered at the incipient stage.
The technique for the departure stall is simply to set-up in take-off configuration at around Vx, then to set-up an unusually high nose attitude and wait until there's a stall indication - obviously this is done at a safe height and after the appropriate checks. Recovery is simply to prevent further yaw and relax the back pressure. Generally it's a ho-hum exercise but there's an obvious risk if continued beyond incipient with significant yaw.
I've also not seen an authoritative definition of a "whip stall", but I've always presumed it was a loose term for an accelerated stall.
HFD
The technique for the departure stall is simply to set-up in take-off configuration at around Vx, then to set-up an unusually high nose attitude and wait until there's a stall indication - obviously this is done at a safe height and after the appropriate checks. Recovery is simply to prevent further yaw and relax the back pressure. Generally it's a ho-hum exercise but there's an obvious risk if continued beyond incipient with significant yaw.
I've also not seen an authoritative definition of a "whip stall", but I've always presumed it was a loose term for an accelerated stall.
HFD
It's not a whip stall, simply a stall with lots of power on. And because it's done at 1G, it's not accelerated in any fashion. Safe as houses !!
I have taught many students things that are not in the syllabus, simply because they were highly realistic scenarios that other instructors did not have the willingness (or experience) to demonstrate.
Find an appropriate Unusual Attitude experienced instructor, and learn how to efficiently and safely recover from ANY 3D position. The training will be invaluable whether you then go on to fly a C150, Lancair, or B757.
I have taught many students things that are not in the syllabus, simply because they were highly realistic scenarios that other instructors did not have the willingness (or experience) to demonstrate.
Find an appropriate Unusual Attitude experienced instructor, and learn how to efficiently and safely recover from ANY 3D position. The training will be invaluable whether you then go on to fly a C150, Lancair, or B757.
Join Date: Jan 2006
Location: cambs.
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
Centaurus
i spend 600-1000 hours a year in 172's flying at 40-50% power 10 deg flap and 60-70 kts taking pictures. The hours builder who sits next to me needs to understand how far/close he is to the stall and how the plane feels in slow flight with power on.
As a previous poster says approaching the power on stall gradually is fairly benign and necessary. Published stall speeds of 54kts power off translate to nearly nil airspeed on full power with a ROC of 10 feet a year.
Freind of mine "Reversed" his cesspit into trees after the wx clamped in over inhospitable terrain. Saved his life. Probably best for most to stick to the envelope they believe in though.
As a previous poster says approaching the power on stall gradually is fairly benign and necessary. Published stall speeds of 54kts power off translate to nearly nil airspeed on full power with a ROC of 10 feet a year.
Freind of mine "Reversed" his cesspit into trees after the wx clamped in over inhospitable terrain. Saved his life. Probably best for most to stick to the envelope they believe in though.
Join Date: May 2001
Location: Far East
Posts: 437
Likes: 0
Received 0 Likes
on
0 Posts
After a couple of hundred hours instructing I went up one nice summer evening with a friend to see if I could make the PA28 do anything remotely exciting. Tried stalling with full power and couldn't. Maybe if I'd held it there for long enough it might have slowed down. Oh the joys of low hours confidence..
Oh please let me come and have a go. I reckon I could stall it with the power on 
Might have to get you to sit in the back though
Did you try it when out of trim (rudder)? That normally gets the world looking exciting. And that's how people tend to get bitten, looking over their shoulder, trying to turn back etc...
Might have to get you to sit in the back though
Did you try it when out of trim (rudder)? That normally gets the world looking exciting. And that's how people tend to get bitten, looking over their shoulder, trying to turn back etc...
There are 4 stall configurations on the current LST/LPC form: idle/clean, final turn, approach, and departure.
If you look at the training syllabus AMC-FCL 1.125 there is no mention of such a manoeuvre!
Join Date: Jul 2003
Location: uk
Posts: 1,042
Likes: 0
Received 0 Likes
on
0 Posts
mms://media.americanflyers.net/asf/AF_FAA_Stalls.asf
http://www.americanflyers.net/resources/faa_videos.asp
Don't know how many times this film as been copied (probably exists recorded in all formats from cine to dvd) but worth a look!
Seem to remember the highly uncoordinated steep turn to stall in PA28 140 produced the sort of manouvre a Sopwith pilot would be proud of!
http://www.americanflyers.net/resources/faa_videos.asp
Don't know how many times this film as been copied (probably exists recorded in all formats from cine to dvd) but worth a look!
Seem to remember the highly uncoordinated steep turn to stall in PA28 140 produced the sort of manouvre a Sopwith pilot would be proud of!
Whopity: that's a bit of a nit pick old chap. 
For the avoidance of doubt, the full title of the "examiner's record" and the application form are "Form LST/LPC SPA, Skill Test Issue 3 (SRG\1157)" and "Form LST/LPC SPA/MPA Issue 8 (SRG\1119)" respectively.
I don't doubt what you say about FCL but according to the guidance attached to 1157 the requirement is for a fully developed stall plus one of the other 3 at the examiner's discretion.
HFD
For the avoidance of doubt, the full title of the "examiner's record" and the application form are "Form LST/LPC SPA, Skill Test Issue 3 (SRG\1157)" and "Form LST/LPC SPA/MPA Issue 8 (SRG\1119)" respectively.
I don't doubt what you say about FCL but according to the guidance attached to 1157 the requirement is for a fully developed stall plus one of the other 3 at the examiner's discretion.
HFD
Join Date: Dec 2003
Location: Central Africa
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
I'm a JAR instructor, currently teaching on the Ikarus C42. For those unfamiliar, this is a microlight 3 axis i.e. a normal light aircraft, except very light... It has 100 hp which may not sound a lot, but with less than 450kgs to haul, makes this maneuvre more dramatic than just about anything except probably a high power aerobatic aircraft.
Teaching the departure stall results in near vertical pitch angles.... interesting!
Teaching the departure stall results in near vertical pitch angles.... interesting!
Join Date: Jul 2003
Location: uk
Posts: 1,042
Likes: 0
Received 0 Likes
on
0 Posts
Pre JAR the idea was to teach students to recover from all types of stall (including spins) then leave it up to the examiner to decide what to test.
Now we seem to be worrying about exactly what type of stall and technique is required to pass the JAR test. Its turned into the CPL test. Monkey see monkey do.
My pre JAR tests were more demanding as much more was covered in the flight test. Not to say we can't do the same now except you cannot fail someone who might do a bad recovery from say a steep turn stall, or poor climbing IF.
A candidate did not just pass or fail, an overview of the students ability was taken into account and a judgement made. Its still done now but with fixed fences to jump over.
Now we seem to be worrying about exactly what type of stall and technique is required to pass the JAR test. Its turned into the CPL test. Monkey see monkey do.
My pre JAR tests were more demanding as much more was covered in the flight test. Not to say we can't do the same now except you cannot fail someone who might do a bad recovery from say a steep turn stall, or poor climbing IF.
A candidate did not just pass or fail, an overview of the students ability was taken into account and a judgement made. Its still done now but with fixed fences to jump over.
Dancing with the devil, going with the flow... it's all a game to me.
Join Date: May 2000
Location: England
Posts: 1,688
Likes: 0
Received 0 Likes
on
0 Posts
It's good to see continuity across the board amongst instructors as always on PPRuNe! ha 
Seriously though, an awful lot cannot be taught on an FIC course (time restrictions, etc) but when you actually get into the job you begin to discover just how little continuity amongst us all there really is! I guess there's little that can be done for this issue other than an active input from CFI's and experienced instructors and a fuller, more thorough, syllabus/guidelines for instructors. Perhaps the instructor seminars create some sort of unity?
Everywhere you go things are taught and done differently and it kinda grates on my nerves somewhat that this state of affairs exists - the amount of students I've flown with who have said "ooh, that's different from the last instructor I flew with".... some of that you can put down to student misunderstanding but a lot is down to us all teaching in our own way. As long as we don't reinvent the wheel I guess it's not so bad but getting back on topic....
Full power on stalls and recovery at JAA PPL stage? It's not in the syllabus and certainly not something I teach.
VFE.
Seriously though, an awful lot cannot be taught on an FIC course (time restrictions, etc) but when you actually get into the job you begin to discover just how little continuity amongst us all there really is! I guess there's little that can be done for this issue other than an active input from CFI's and experienced instructors and a fuller, more thorough, syllabus/guidelines for instructors. Perhaps the instructor seminars create some sort of unity?
Everywhere you go things are taught and done differently and it kinda grates on my nerves somewhat that this state of affairs exists - the amount of students I've flown with who have said "ooh, that's different from the last instructor I flew with".... some of that you can put down to student misunderstanding but a lot is down to us all teaching in our own way. As long as we don't reinvent the wheel I guess it's not so bad but getting back on topic....
Full power on stalls and recovery at JAA PPL stage? It's not in the syllabus and certainly not something I teach.
VFE.
Join Date: Oct 2003
Location: UK
Age: 50
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
VFE
Although it isn't taught as part of the PPL course my CFI told me to show a student what the stall is like. Here is why.
The stall scenario is on the approach to the runway. Flaps, medium power setting and pulling too hard. On the PPL and CPL you recover at the incipient stage, ie buffet or stall warner.
However if you take the aircraft further into the stall then it could depart into a spin or a spiral dive. The wing drop is very marked. (As I found out on my mutuals).
It is very important to show a student why we recover at the incipient stage.
I have been led to believe that the Cessna that crashed and killed a young lad on a solo flight in the summer was caused by the A/C departing controlled flight.
If an instructor is worried about flying the sortie, ask for a demonstration from the CFI it may save your life.
Although it isn't taught as part of the PPL course my CFI told me to show a student what the stall is like. Here is why.
The stall scenario is on the approach to the runway. Flaps, medium power setting and pulling too hard. On the PPL and CPL you recover at the incipient stage, ie buffet or stall warner.
However if you take the aircraft further into the stall then it could depart into a spin or a spiral dive. The wing drop is very marked. (As I found out on my mutuals).
It is very important to show a student why we recover at the incipient stage.
I have been led to believe that the Cessna that crashed and killed a young lad on a solo flight in the summer was caused by the A/C departing controlled flight.
If an instructor is worried about flying the sortie, ask for a demonstration from the CFI it may save your life.
Join Date: Dec 2003
Location: Central Africa
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
Llanfairpg
Its unlikely a syllabus will quote any specific power setting for a type of stall, because this will vary according to aircraft & engine type. However if an instructor was wishing to teach recovery from a stall in the departure phase, to be realistic, this would need to be done with full power, as on most GA aircraft that is what is used on climbout.
Some aircraft are more prone to this type of stall than others. For some the angle of attack required can easily be accidently reached being not that great. Having said that I have have students nearly stall an Ikarus C42 after take-off, by just having no sense of reality about the kind of pitch angle required and pulling back to near vertical!!
Its unlikely a syllabus will quote any specific power setting for a type of stall, because this will vary according to aircraft & engine type. However if an instructor was wishing to teach recovery from a stall in the departure phase, to be realistic, this would need to be done with full power, as on most GA aircraft that is what is used on climbout.
Some aircraft are more prone to this type of stall than others. For some the angle of attack required can easily be accidently reached being not that great. Having said that I have have students nearly stall an Ikarus C42 after take-off, by just having no sense of reality about the kind of pitch angle required and pulling back to near vertical!!
Join Date: Dec 2005
Location: SE England
Age: 50
Posts: 120
Likes: 0
Received 0 Likes
on
0 Posts
Just my two penneth here,
My opinion would be to think about the aircraft you're flying. If the aircraft is going to do something dangerous in a full power stall, then it's probably for the best not to do it, but a thorough brief to the student should be advisable, and plenty of stall/spin prevention training. If it's not particularly dangerous at height, then why not extend the ability of the student? One of the major causes of fatalities is the departure stall, and this is virtually always a full power situation.
To say that the recovery action should be taken at the incipient stage is a little bit strange to me. If the 'incipient stage' is always recognised, why do stalls occur? Please don't lose sight of the fact that not all aircraft buffet significantly prior to the stall, not all aircraft have stall warners, and a stall warner may or may not work when needed. The 'incipient stage' in some aircraft may only manifest itself as a reduction in airspeed, and many aircraft climb very close to the stall itself!
My opinion would be to think about the aircraft you're flying. If the aircraft is going to do something dangerous in a full power stall, then it's probably for the best not to do it, but a thorough brief to the student should be advisable, and plenty of stall/spin prevention training. If it's not particularly dangerous at height, then why not extend the ability of the student? One of the major causes of fatalities is the departure stall, and this is virtually always a full power situation.
To say that the recovery action should be taken at the incipient stage is a little bit strange to me. If the 'incipient stage' is always recognised, why do stalls occur? Please don't lose sight of the fact that not all aircraft buffet significantly prior to the stall, not all aircraft have stall warners, and a stall warner may or may not work when needed. The 'incipient stage' in some aircraft may only manifest itself as a reduction in airspeed, and many aircraft climb very close to the stall itself!