Power On Stalls, what's the point?
Moderator
Joined: Feb 2000
Aviation Qualifications: CPL
Posts: 14,480
Likes: 178
From: UK
Half a dozen years ago I was asked on behalf of AAIB to do a bit of flight testing for them. They had had an experienced pilot (although not on that particular type) go from a full power climb fatally into the ground with high speed and bank angle. Nobody could (initially) work out why. The certification standard against which that aircraft was approved hadn't required full power stalls to be evaluated.
We had a suspicion that the pilot had probably not judged the pitch attitude correctly (this type had a very low cockpit coaming compared to what he was used to), and might have entered a full power stall. This was an unknown area of flight in that type, so I went to take a look at it.
Unlike an idle stall which gave plenty of warning and no wing drop, at full power this gave no warning, and the aircraft went straight into incipient spin - disconcerting when I found it the first time.
We theorised (you can never be sure, but I'm convinced) that the aircraft went from a full power stall into a spin, which self-recovered into a spiral dive (a common characteristic of small aeroplanes). Given this was at about 500ft, he had little time or height to play with - so he died and the aircraft was destroyed.
Had that pilot been more familiar with the aircraft (he had about 3000 hrs I see from my notes, but nothing on type and only a few hours on similar types) and/or power-on stalls, he would have probably recognised the impending power-on stall and recovered, or have recognised it when it occurred and responded in a manner that did not cause a spin/spiral dive/ground impact.
We quietly changed the rules at that time to include assessment of full power stalls during certification of similar aircraft.
So, my vote is that practicing power-on stalling is necessary and appropriate (then again, I always have anyhow, and have never had a problem with FAA checkouts).
Anyhow, stalling is fun - where's the problem
. I had a very happy morning this morning practicing various stalls with an instructor to get me back into currency, and have no problems with it at-all. (Although comparing notes over a coffee afterwards, the FI had about 1/3 my hours - I'm getting old 
)
I recall a checkout instructor once who made me fly a very precise figure-of-eight around a couple of convenient landmarks. Very very good discipline, I've practiced it occasionally since and it's a useful handling practice, particularly if there's significant wind.
G
We had a suspicion that the pilot had probably not judged the pitch attitude correctly (this type had a very low cockpit coaming compared to what he was used to), and might have entered a full power stall. This was an unknown area of flight in that type, so I went to take a look at it.
Unlike an idle stall which gave plenty of warning and no wing drop, at full power this gave no warning, and the aircraft went straight into incipient spin - disconcerting when I found it the first time.
We theorised (you can never be sure, but I'm convinced) that the aircraft went from a full power stall into a spin, which self-recovered into a spiral dive (a common characteristic of small aeroplanes). Given this was at about 500ft, he had little time or height to play with - so he died and the aircraft was destroyed.
Had that pilot been more familiar with the aircraft (he had about 3000 hrs I see from my notes, but nothing on type and only a few hours on similar types) and/or power-on stalls, he would have probably recognised the impending power-on stall and recovered, or have recognised it when it occurred and responded in a manner that did not cause a spin/spiral dive/ground impact.
We quietly changed the rules at that time to include assessment of full power stalls during certification of similar aircraft.
So, my vote is that practicing power-on stalling is necessary and appropriate (then again, I always have anyhow, and have never had a problem with FAA checkouts).
Anyhow, stalling is fun - where's the problem
. I had a very happy morning this morning practicing various stalls with an instructor to get me back into currency, and have no problems with it at-all. (Although comparing notes over a coffee afterwards, the FI had about 1/3 my hours - I'm getting old )
What sort of thing would you be asked to do as a ground reference manoeuvre?
G
Last edited by Genghis the Engineer; 9th January 2005 at 15:41.
Joined: Mar 2000
Posts: 1,639
Likes: 0
From: TL487591
Unlike an idle stall which gave plenty of warning and no wing drop, at full power this gave no warning, and the aircraft went straight into incipient spin - disconcerting when I found it the first time.
The aircraft concerned was a Cessna 152. Like the vast majority of aircraft in the GA fleet, the 152 is certificated under FAA Part 23, and most foreign certification (including our own) is substantially on the basis of that testing.
Part 23.201 defines the stall tests which the aircraft must be put through for type approval, and it will be of no surprise that power-on stalls at full power are specified as part of the test program for aircraft such as the 152. A requirement for a satisfactory pass of 23.201 is an early and pronounced stall warning prior to a stall.
There should be no suggestion that a C152 requires the extreme skills of a test pilot in order to perform a power on stall without the risk of a spin. Indeed, tens of thousands of FAA pilots got their wings in 152 and all will have had to demonstrate proficiency at the manoeuvre.
2D
Joined: May 1999
Aviation Qualifications: ATP+Mil
Posts: 27,400
Likes: 857
From: Quite near 'An aerodrome somewhere in England'
OK - full power stalls recovering at the first stall warning (i.e. at the incipient stall) I can accept. Deliberately continuing to the fully-developed stage might be reasonable for certification purposes, but the average pilot should certainly not be expected to take a full power stall to the fully-developed stage.
Later edited to add: The only time I have deliberately induced a full power stall in recent years was when checking the rigging of an a/c after it had been susbtantially rebuilt. Even then it was only to the incipient stage at a 1 kt per second deceleration rate - certainly not a deliberate pitch to the full stall.
Later edited to add: The only time I have deliberately induced a full power stall in recent years was when checking the rigging of an a/c after it had been susbtantially rebuilt. Even then it was only to the incipient stage at a 1 kt per second deceleration rate - certainly not a deliberate pitch to the full stall.
Last edited by BEagle; 9th January 2005 at 17:28.
Joined: Sep 2003
Posts: 0
Likes: 0
From: UK,Twighlight Zone
I agree with Beagle here, while it is important for a pilot to be familier with all aspects of handling the aircraft they fly there is is little reason for psuhing the envelope to the limit. Power on stalls to the warner or buffet make sense but not really full developed?
On frequent occassions I have full power stalled my 152's and excercise has a number of times ended up in a spin. Fun but I think for the unwary it could be a problem especially with spinning not being taught as part of the PPL anymore.
Personally I love spinning my aircraft for the entertainment value but prefer to do it intentionally so I can tie things down first!!
On frequent occassions I have full power stalled my 152's and excercise has a number of times ended up in a spin. Fun but I think for the unwary it could be a problem especially with spinning not being taught as part of the PPL anymore.
Personally I love spinning my aircraft for the entertainment value but prefer to do it intentionally so I can tie things down first!!
Guest
Posts: n/a
2 Donkeys and Say Again Slowly
The Archer is not cleared for spinning and to attempt a full power stall, with the CoG near the rear limit is, in my opinion, extremely foolish.
The aircraft could easily enter an spin and be unrecoverable due to the CoG. Remember, it is not cleared for intentional spinning, so spin recovery is test pilot work and I prefer to leave that kind of stuff to John Farley and Ghengis
SaS, you are assuming that the instructor briefed the manouvre requested, which was not the case.
He also asked me to change fuel tanks at the hold, following a landing and before the next departure, without a run up check and got annoyed when I insisted on doing a power check before departure, saying it was a waste of time.
He was accident waiting to happen, in my opinion, and I must say not in line with my experience of most US instructors, who I've found to be professional in approach.
And as a PPL with a few hundred hours stick time (and over 200 on the PA28), I know enough to recognise instructors who do not act professionally.
Also, 2 Donks, fine to quote the FARs, but bear in mind that there are not a panacea for all evils; Have you ever read Dick Collins feelings about the past requirement for flying a light twin, on one, low level, around the minimum control speed?
He claims a lot of people died because of this requirement.
The Archer is not cleared for spinning and to attempt a full power stall, with the CoG near the rear limit is, in my opinion, extremely foolish.
The aircraft could easily enter an spin and be unrecoverable due to the CoG. Remember, it is not cleared for intentional spinning, so spin recovery is test pilot work and I prefer to leave that kind of stuff to John Farley and Ghengis
SaS, you are assuming that the instructor briefed the manouvre requested, which was not the case.
He also asked me to change fuel tanks at the hold, following a landing and before the next departure, without a run up check and got annoyed when I insisted on doing a power check before departure, saying it was a waste of time.
He was accident waiting to happen, in my opinion, and I must say not in line with my experience of most US instructors, who I've found to be professional in approach.
And as a PPL with a few hundred hours stick time (and over 200 on the PA28), I know enough to recognise instructors who do not act professionally.
Also, 2 Donks, fine to quote the FARs, but bear in mind that there are not a panacea for all evils; Have you ever read Dick Collins feelings about the past requirement for flying a light twin, on one, low level, around the minimum control speed?
He claims a lot of people died because of this requirement.
Last edited by Final 3 Greens; 9th January 2005 at 18:09.
Joined: Aug 2000
Posts: 3,648
Likes: 2
From: UK
As for the statement that a power on stall is unrealistic.... Oh really. I'm sure Bookworm could dig up a few reports of people who've killed themselves that way.
I also remember doing some training in a 152 (I think it was a club checkride) with the then Chief Pilot of Marshalls. He suggested that we try a full power stall. As I was setting up for it, I asked "So what am I expecting to happen then?". He turned to me and said, in his inimitable deadpan tone, "I have no idea, I've never tried one before."
I also agree with BEagle that there seems to be no reason to take such an exercise further than the incipient stage.
Joined: Mar 2000
Posts: 1,639
Likes: 0
From: TL487591
Also, 2 Donks, fine to quote the FARs, but bear in mind that there are not a panacea for all evils; Have you ever read Dick Collins feelings about the past requirement for flying a light twin, on one, low level, around the minimum control speed?
May I say that I think you are too tied up in your own story and not in that of the original poster.
He was in a 152 with, so far as we know, a C of G that was perfectly acceptable. By his own admission, he mishandled the recovery from a stall, and was failed by the instructor.
Your advice was to swap instructors, and I disagree with you.
It is as simple as that.
Meanwhile, I'll keep on with the FARs and the PTS. Bombproof they are not, but they are far clearer than the corresponding lack of documentation published in JAR-land.
And as a PPL with a few hundred hours stick time (and over 200 on the PA28)
2D
Joined: Nov 2000
Posts: 3,443
Likes: 1
From: Cambridge, England, EU
I also remember doing some training in a 152 (I think it was a club checkride) with the then Chief Pilot of Marshalls. He suggested that we try a full power stall. As I was setting up for it, I asked "So what am I expecting to happen then?". He turned to me and said, in his inimitable deadpan tone, "I have no idea, I've never tried one before."
That sounds like the people I trained with!Seriously though ... knowing that the only stupid question is the one I don't ask ...
I sure I recall being in a little aeroplane with power on (don't recall whether it was full or not, don't recall the flap setting either, er, not very good at this am I) and the stick back as far as it would go and the nose pointing at the sky and the thing simply refusing to stall. In that the warner was blaring away, but the nose didn't drop and a wing didn't drop and whilst we weren't making a lot of forward progress we weren't making much downward progress either. Sure the wings must have been at least partly stalled, but the thing was still flying after a fashion and we decided it wasn't a "stall". So, as the thing wouldn't "stall" in this configuration with this power setting the instructor decided that it was reasonable that I'd failed to demonstrate a recovery from the non-existent stall!!
So, the stupid question is:
Are there ranges of configuration and power setting for particular aircraft where this behaviour is expected - it stays upright, mushes along vaguely forwards, nose doesn't drop, wing doesn't drop, no more elevator to bring into play?
Joined: Aug 2000
Posts: 3,648
Likes: 2
From: UK
Sure the wings must have been at least partly stalled,
Guest
Posts: n/a
2 Donkeys
I don't want to get into an argument, but you said...
Now that wording is ambiguous and I took it as personal criticism, but apparently it was not.
With all respect, it was not as simple as smith being failed, since we also know that another instructor contradicted his instructor.
I would not expect that kind of contradiction in a professional FBO or school. Why should one instructor disagree with another to a student? Who knows, but I can understand why Smith is feeling confused and disconcerted.
He (or she) is also paying for professional service and does not deserves mixed messages.
If this situation makes smith feel uncomfortable enough, then let him consider finding another school or instructor.
If the same mishandling occurs again, then the result will be the same.
I don't want to get into an argument, but you said...
So F3G, you are suggesting that if during the course of a checkout, you demonstrate a basic handling flaw, the best course of action is to blame the instructor and find a new one....?
With all respect, it was not as simple as smith being failed, since we also know that another instructor contradicted his instructor.
I would not expect that kind of contradiction in a professional FBO or school. Why should one instructor disagree with another to a student? Who knows, but I can understand why Smith is feeling confused and disconcerted.
He (or she) is also paying for professional service and does not deserves mixed messages.
If this situation makes smith feel uncomfortable enough, then let him consider finding another school or instructor.
If the same mishandling occurs again, then the result will be the same.
Joined: Aug 1999
Posts: 458
Likes: 0
From: U.K.
Several times in the past, when I have asked a PPL on a check ride to go around from landing config without previous briefing, he has pitched up before adding power. This is a fact, also if an a/c on the runway is a bit slow on taking off, the tendancy for a pilot on finals is to slightly level off while looking at the a/c on the ground, setting up for a power on stall. After a sneaky assesment of a pilot on a checkride, I would at a safe hieght talk him/her into a power on climbing stall with 20flap on a C150, and I have always been thanked for the excercise. Pilot who say "Iwould never get in that situation" frighten me.
Guest
Posts: n/a
2 issues here?
(a) Differences between UK and USA training syllabi.
(b) Differences between individual instructors performing training and checkouts.
As far as (a) is concerned , perhaps a CAA authority could explain why ground reference manouevres and departure stalls are unnecessary in UK/JAA PPL training. Likewise, perhaps an FAA authority could explain why they are considered essential in the US. Then we can each make a more informed judgement.
As far as (b) is concerned, that debate could last quite some time as there are so many aspects of flying technique which lend themselves to personal interpretation/preferences - see the instructor forum.
(a) Differences between UK and USA training syllabi.
(b) Differences between individual instructors performing training and checkouts.
As far as (a) is concerned , perhaps a CAA authority could explain why ground reference manouevres and departure stalls are unnecessary in UK/JAA PPL training. Likewise, perhaps an FAA authority could explain why they are considered essential in the US. Then we can each make a more informed judgement.
As far as (b) is concerned, that debate could last quite some time as there are so many aspects of flying technique which lend themselves to personal interpretation/preferences - see the instructor forum.
Flies for fun
Joined: Feb 2000
Posts: 789
Likes: 0
From: Wishing it was somewhere sunny!
F3G, I've taken Archers into full power on stalls, never ever noticed any Cof G issues! Sure you mean Mr Pipers Archers?
Punch ups aside, How did you get on with the stalls smith?
A fine can of worms you opened here
Punch ups aside, How did you get on with the stalls smith?
A fine can of worms you opened here
Guest
Posts: n/a
Sensible
Were you in the utility or normal category?
What was the c of g?
Would you still do it with a 90kg observer in the rear seat and three heavy flight bags in the luggage compartment?
The Archer is a very docile aeroplane, but it will bite if provoked enough.
Were you in the utility or normal category?
What was the c of g?
Would you still do it with a 90kg observer in the rear seat and three heavy flight bags in the luggage compartment?
The Archer is a very docile aeroplane, but it will bite if provoked enough.
Last edited by Final 3 Greens; 10th January 2005 at 07:35.
Moderator
Joined: Feb 2000
Aviation Qualifications: CPL
Posts: 14,480
Likes: 178
From: UK
FAR-23 defines the stall as the point at which the aircraft departs controlled flight or the pitch control is on the stop. Therefore by definition, the aircraft can stall at any weight and CG condition - it's just that the characteristics of the stall may change.
2D - you missed my argument a bit. I was not arguing that all pilots should be taking an aircraft to a fully developed power-on stall (although I'm as-yet unconvinced it actually does any harm in a sorted aircraft). No, my argument was that a power-on stall can be achieved inadvertently by a very experienced pilot (and thus probably an inexperienced pilot too), and that it's clues and warnings are not identical to those of of an idle stall. Therefore a pilot should be made fully aware of what it looks like and how to recover safely from it. I wouldn't have a problem with that involving just taking the aircraft to incipient if the stall characteristics are particularly nasty.
In that context, I think that the FAA instructor was quite right to refuse to sign off our original poster if he couldn't deal with the power-on stall - although it might have been more polite to turn the sortie into a bit of instruction in the subject and then do a second checkride a little later. I'd particularly bear in mind that this was a 152, which takes some pretty gross mishandling to spin - even from a power-on stall.
G
2D - you missed my argument a bit. I was not arguing that all pilots should be taking an aircraft to a fully developed power-on stall (although I'm as-yet unconvinced it actually does any harm in a sorted aircraft). No, my argument was that a power-on stall can be achieved inadvertently by a very experienced pilot (and thus probably an inexperienced pilot too), and that it's clues and warnings are not identical to those of of an idle stall. Therefore a pilot should be made fully aware of what it looks like and how to recover safely from it. I wouldn't have a problem with that involving just taking the aircraft to incipient if the stall characteristics are particularly nasty.
In that context, I think that the FAA instructor was quite right to refuse to sign off our original poster if he couldn't deal with the power-on stall - although it might have been more polite to turn the sortie into a bit of instruction in the subject and then do a second checkride a little later. I'd particularly bear in mind that this was a 152, which takes some pretty gross mishandling to spin - even from a power-on stall.
G
Flies for fun
Joined: Feb 2000
Posts: 789
Likes: 0
From: Wishing it was somewhere sunny!
F£G the answer is I would never fly an aircraft which was loaded outside of the Cof G limits whether it was to practice stalls or otherwise! Providing that the aircraft was within the manufacturers CoG limits, I cannot envisage a problem (and we are talking training spam cans here)
Guest
Posts: n/a
Sensible
Fair enough about flying out of limits, but that wasn't the case, the aircraft was just in w&b. I know that, because I was doing a BFR and had calculated the numbers and shown them to the instructor before departure.
So, say the aft limit was 93" and the aircraft was at 92 and a bit and 10lbs under gross, how would you feel then?
IF you inadvertently got into a spin (IF) from a full power stall (and the pitch up angle to stall an Archer at full power is pretty steep), how comfortable would you feel about recovering in an aircraft that was not certified for spinning?
So it's a matter of risk judgement isn't it? The Archer certainly isn't a hot ship, so you might well get away with no spin or recover from the spin.
But with a very rear c of g, previous experience in PA28-140s, which were cleared to spin within a very narrow forward c of g envelope, would not persuade me to take the risk of encountering a flat spin.
Fair enough about flying out of limits, but that wasn't the case, the aircraft was just in w&b. I know that, because I was doing a BFR and had calculated the numbers and shown them to the instructor before departure.
So, say the aft limit was 93" and the aircraft was at 92 and a bit and 10lbs under gross, how would you feel then?
IF you inadvertently got into a spin (IF) from a full power stall (and the pitch up angle to stall an Archer at full power is pretty steep), how comfortable would you feel about recovering in an aircraft that was not certified for spinning?
So it's a matter of risk judgement isn't it? The Archer certainly isn't a hot ship, so you might well get away with no spin or recover from the spin.
But with a very rear c of g, previous experience in PA28-140s, which were cleared to spin within a very narrow forward c of g envelope, would not persuade me to take the risk of encountering a flat spin.