Wing drop during stall
Join Date: Sep 2006
Location: Scotland
Age: 84
Posts: 1,434
Likes: 0
Received 0 Likes
on
0 Posts
And yes crash one a kick up the arse is required. Its all to do with flow over the aerofoil and when the boundary layer becomes unstuck. Although I would slightly disagree with the turbulence comments because sometimes the engineers induce it with vortex generators because it delays the boundary layer becoming unstuck.
Anyway I do think there is more to it than saying stalls are caused by pilot error. Of course they are, either in error or on purpose but they have always been caused by the pilot.
I seem to remember a gliding instructor flying a high performance laminar flow piece of tupperware at 3000ft when it started to rain, 10 mins later he was standing in a field thinking "what the hell was that about". Parasite drag?
Join Date: Feb 2009
Location: England
Posts: 858
Likes: 0
Received 0 Likes
on
0 Posts
Pace--I think you are confusing a recovery from the approach to the stall with a fully developed stall.
This is the updated Airbus information.
http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf
This is the important bit
The priority is reducing the angle of attack. There have been numerous situations where flight crews did not prioritize this and instead prioritized power and maintaining altitude. This will also address autopilot induced full back trim.
This is the updated Airbus information.
http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf
This is the important bit
The priority is reducing the angle of attack. There have been numerous situations where flight crews did not prioritize this and instead prioritized power and maintaining altitude. This will also address autopilot induced full back trim.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
No mate it was the wing drop I was on about.
I thought they always dropped as well until I realised I had stalled the same tommy about 15 times and it hadn't wing dropped. Next time I demo'd it I did one as normal and one annoying it. The one where I annoyed it had a wing drop.
The likely hood is though that if your not expecting it you will annoy it so therefore you will get a drop.
But it doesn't have anything to do with where the ASI is pointing the Crit AoA stays the same.
I thought they always dropped as well until I realised I had stalled the same tommy about 15 times and it hadn't wing dropped. Next time I demo'd it I did one as normal and one annoying it. The one where I annoyed it had a wing drop.
The likely hood is though that if your not expecting it you will annoy it so therefore you will get a drop.
But it doesn't have anything to do with where the ASI is pointing the Crit AoA stays the same.
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Pull what
I have thousands of hard weather hours mainly in piston twins and singles and am very aware of conventional stall recovery!
I would go further and consider my strengths as a handling pilot ( I can get other ppruners who have flown with me 2 who I gave Citation SICs to)
I don't disagree with you BEAgle or Mad Jock as that is my stall recovery instincts too.
The method taught by 3 FAA examiners leans more to power/ thrust and maintaining altitude relying on power and a very gradual reduction in AOA.
The CItation is an above wing engined jet which naturally reduce AOA on application of max thrust so maybe that is part of the reason ?
I know when I accidentally reverted to my instincts and recovered as I would do a Seneca twin I got my knucles rapped and saw with my own eyes a large loss of altitude.
Mad Jock made a valid point concerning a max N1 stall in the climb and appeared to take offense at tipping the nose not only to reduce AOH but to tap onto airframe potential energy for more airflow!
Contrary to his argument against power and maintaing altitude ?
BEAgle considers any FAA examiner to be an idiot who should be shot at dawn ; )
Many heavier jets have used power recoveries! Ok maybe things are changing and I would like to know the recommendations for the CITATION with this new recovery approach as i have seen the large height loss with a standard recovery ? I don't really disagree with much of what any of the three of you have said
Pace
I have thousands of hard weather hours mainly in piston twins and singles and am very aware of conventional stall recovery!
I would go further and consider my strengths as a handling pilot ( I can get other ppruners who have flown with me 2 who I gave Citation SICs to)
I don't disagree with you BEAgle or Mad Jock as that is my stall recovery instincts too.
The method taught by 3 FAA examiners leans more to power/ thrust and maintaining altitude relying on power and a very gradual reduction in AOA.
The CItation is an above wing engined jet which naturally reduce AOA on application of max thrust so maybe that is part of the reason ?
I know when I accidentally reverted to my instincts and recovered as I would do a Seneca twin I got my knucles rapped and saw with my own eyes a large loss of altitude.
Mad Jock made a valid point concerning a max N1 stall in the climb and appeared to take offense at tipping the nose not only to reduce AOH but to tap onto airframe potential energy for more airflow!
Contrary to his argument against power and maintaing altitude ?
BEAgle considers any FAA examiner to be an idiot who should be shot at dawn ; )
Many heavier jets have used power recoveries! Ok maybe things are changing and I would like to know the recommendations for the CITATION with this new recovery approach as i have seen the large height loss with a standard recovery ? I don't really disagree with much of what any of the three of you have said
Pace
Join Date: Sep 2011
Location: europe
Age: 49
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
The sim excersise that is being referred to does not require the student to recover an aircraft that has actually stalled. The recovery should be effected at the FIRST SIGN of an impending stall, be this stick shake, aural warning or aerodynamic buffet.
In many jet types it is indeed possible to recover PRIOR to the stall with zero or a very small loss of height. The outcome will be dependent to some degree on pilot handling, and how close to the critical angle the aircraft gets prior to the natural or artificial warning. If there is a good margin, you have a good chance of achieving zero loss of height.
Pace, you have referred to the Citation's high mounted powerplants. This is an old chestnut that has little or no relevance when discussing stall recovery in a jet aircraft. Consider the situation as you approach the stall in your Citation with a low value of N1 set (arguably a common lead up to a real life stall situation). Your technique of simply adding power will not on its own effect any immediate change to the angle of attack due to the time required for the engines to spool up. (they too are operating at an increased AoA). Similarly, if you are foolish enough to find yourself approaching to stall with a high power setting, any small addition of thrust is hardly likely to make a jot of difference. In either event you would be well advised to reduce the angle of attack by use of forward elevator. This will lead to a reduction in lift, and an inevitable loss of altitude.
By all means add as much thrust as you wish, but a change of angle of attack is highly desirable, and elevator is going to do it for you first.
In many jet types it is indeed possible to recover PRIOR to the stall with zero or a very small loss of height. The outcome will be dependent to some degree on pilot handling, and how close to the critical angle the aircraft gets prior to the natural or artificial warning. If there is a good margin, you have a good chance of achieving zero loss of height.
Pace, you have referred to the Citation's high mounted powerplants. This is an old chestnut that has little or no relevance when discussing stall recovery in a jet aircraft. Consider the situation as you approach the stall in your Citation with a low value of N1 set (arguably a common lead up to a real life stall situation). Your technique of simply adding power will not on its own effect any immediate change to the angle of attack due to the time required for the engines to spool up. (they too are operating at an increased AoA). Similarly, if you are foolish enough to find yourself approaching to stall with a high power setting, any small addition of thrust is hardly likely to make a jot of difference. In either event you would be well advised to reduce the angle of attack by use of forward elevator. This will lead to a reduction in lift, and an inevitable loss of altitude.
By all means add as much thrust as you wish, but a change of angle of attack is highly desirable, and elevator is going to do it for you first.
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Chubbychopper
I don't disagree with what you say! The stall recovery maybe at incipient where the wing is still flying and at an AOA which is condusive to flight.
As I posted earlier incipient is flavor of the month in training schools but unreal.
The difference bet
Ween incipient and full can be very small you cannot have procedure A for incipient recovery and procedure B for full! That's a joke!
You have to have a recovery method to cover the whole?
Obviously any recovery has to include a reduction in AOA whether in minute gradual amounts or a full bloodied push forward for a large AoA change and a push for potential airframe energy too.
The Citation is recovered in a different way to a PA34 recover it like a PA34 and the VSI will be heading down at a fast rate.
With the new recommendations I prob do need to speak with Cessna
Pace
I don't disagree with what you say! The stall recovery maybe at incipient where the wing is still flying and at an AOA which is condusive to flight.
As I posted earlier incipient is flavor of the month in training schools but unreal.
The difference bet
Ween incipient and full can be very small you cannot have procedure A for incipient recovery and procedure B for full! That's a joke!
You have to have a recovery method to cover the whole?
Obviously any recovery has to include a reduction in AOA whether in minute gradual amounts or a full bloodied push forward for a large AoA change and a push for potential airframe energy too.
The Citation is recovered in a different way to a PA34 recover it like a PA34 and the VSI will be heading down at a fast rate.
With the new recommendations I prob do need to speak with Cessna
Pace
Join Date: Sep 2011
Location: europe
Age: 49
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
I am not familiar with the term "incipient stall." An airplane is either stalled, or it is not. I assume you mean "approaching the stall, or an "impending stall."
Yes, jet training facilities do emphasize recovery from the approach, or first recognition, of an impending stall. This, in my humble opinion is what they should teach. It just so happens that if the aircraft does actually stall, the recovery action is the same.
That's all for me on this thread.
Yes, jet training facilities do emphasize recovery from the approach, or first recognition, of an impending stall. This, in my humble opinion is what they should teach. It just so happens that if the aircraft does actually stall, the recovery action is the same.
That's all for me on this thread.
BEAgle considers any FAA examiner to be an idiot who should be shot at dawn ; )
No-one is suggesting that a large pitch attitude change is needed to reduce AoA, just that a sufficient attitude change is made. That will not cause a massive RoD unless it is grossly mishandled.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Pace mate I didn't take offense. I always have it mind when two pro's are debating a point especially in this forum that there are always a large number of inexperenced reading our words and taking them to heart.
I didn't want any student or for that matter low houred pilot recovering from a departure stall by hoofing the nose down into a decent.
I didn't want any student or for that matter low houred pilot recovering from a departure stall by hoofing the nose down into a decent.
Join Date: Feb 2009
Location: England
Posts: 858
Likes: 0
Received 0 Likes
on
0 Posts
This is the latest from the Airbus chief test pilot
The AoA decrease may be obtained
indirectly by increasing the speed,
but adding thrust in order to increase
the speed leads to an initial adverse
longitudinal effect, which trends to
increase further the AoA (fig. 4).
It is important to know that if such
a thrust increase was applied when
the aircraft is already stalled, the
longitudinal effect would bring the
aircraft further into the stall, to a
situation possibly unrecoverable.
Conversely, the first effect of reducing
the thrust is to reduce the
AoA
----------------------------------------------------
In summary:
FIRST: The AoA MUST BE REDUCED.
If anything, release the
back pressure on stick or column
and apply a nose down pitch input
until out of stall (no longer have
stall indications). In certain cases,
an action in the same direction on
the longitudinal trim may be needed.
Don’t forget that thrust has an
adverse effect on AoA for aircraft
with engines below the wings.
SECOND: When the stall clues
have disappeared, increase the
speed if needed. Progressively
increase the thrust with care, due to
the thrust pitch effect.
In practice, in straight flight without
stick input, the first reaction
when the SW is triggered should be
Relative airflow
Relative airflow Thrust increase
Relative airflow
Thrust reduction
Figure 3
Pitch control
is a direct
AoA command
Figure 4
Adding thrust
leads to an
increase in AoA
Figure 5
Reducing thrust
leads to a
decrease in AoA
to gently push on the stick so as to
decrease the pitch attitude by about
two or three degrees in order to decrease
the AoA below the AoA SW.
During manoeuvres, the reduction
of the AoA is generally obtained
just by releasing the backpressure
on the stick; applying a progressive
forward stick inputs ensures a
quicker reduction of the AoA.
If the SW situation occurs with
high thrust, in addition to the stick
reaction, reducing the thrust may
be necessary.
10. Procedure
As an answer to the stall situation,
a working group gathering the FAA
and the main aircraft manufacturers,
including Airbus, ATR, Boeing,
Bombardier and Embraer, have established
a new generic procedure
titled “Stall Warning or Aerodynamic
Stall Recovery Procedure”
applicable to all aircraft types.
This generic procedure will be published
as an annex to the FAA AC 120.
This new procedure has been established
in the following spirit:
q
The AoA decrease may be obtained
indirectly by increasing the speed,
but adding thrust in order to increase
the speed leads to an initial adverse
longitudinal effect, which trends to
increase further the AoA (fig. 4).
It is important to know that if such
a thrust increase was applied when
the aircraft is already stalled, the
longitudinal effect would bring the
aircraft further into the stall, to a
situation possibly unrecoverable.
Conversely, the first effect of reducing
the thrust is to reduce the
AoA
----------------------------------------------------
In summary:
FIRST: The AoA MUST BE REDUCED.
If anything, release the
back pressure on stick or column
and apply a nose down pitch input
until out of stall (no longer have
stall indications). In certain cases,
an action in the same direction on
the longitudinal trim may be needed.
Don’t forget that thrust has an
adverse effect on AoA for aircraft
with engines below the wings.
SECOND: When the stall clues
have disappeared, increase the
speed if needed. Progressively
increase the thrust with care, due to
the thrust pitch effect.
In practice, in straight flight without
stick input, the first reaction
when the SW is triggered should be
Relative airflow
Relative airflow Thrust increase
Relative airflow
Thrust reduction
Figure 3
Pitch control
is a direct
AoA command
Figure 4
Adding thrust
leads to an
increase in AoA
Figure 5
Reducing thrust
leads to a
decrease in AoA
to gently push on the stick so as to
decrease the pitch attitude by about
two or three degrees in order to decrease
the AoA below the AoA SW.
During manoeuvres, the reduction
of the AoA is generally obtained
just by releasing the backpressure
on the stick; applying a progressive
forward stick inputs ensures a
quicker reduction of the AoA.
If the SW situation occurs with
high thrust, in addition to the stick
reaction, reducing the thrust may
be necessary.
10. Procedure
As an answer to the stall situation,
a working group gathering the FAA
and the main aircraft manufacturers,
including Airbus, ATR, Boeing,
Bombardier and Embraer, have established
a new generic procedure
titled “Stall Warning or Aerodynamic
Stall Recovery Procedure”
applicable to all aircraft types.
This generic procedure will be published
as an annex to the FAA AC 120.
This new procedure has been established
in the following spirit:
q
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Come on Pace has said that he is going to check with cessna
Anyway it seems at last someone has grabbed the bull by the horns and is publishing a best practise which will hopefully cut all the different interpretions of the current methods.
Anyway it seems at last someone has grabbed the bull by the horns and is publishing a best practise which will hopefully cut all the different interpretions of the current methods.
Moderator
The impossible turn
This Youtube clip provides a useful demonstration of wing drop during a stall.
This stall was destined to happen at just about the point where the pilot entered the left turn. The pilot forgot how much drag increase there would be with the turn, made worse by the very small radius of the turn (brought about by the choice to turn in such a confined area).
This video clearly demonstrates several things:
A wing can drop during a stall - but we knew that...
Turns cause lots of drag increase.
An attempt to land from a non stabilized approach can turn out badly,
And, the impossible turn. There was some discussion about the impossible turn recently in another thread on the instructors forum, but the whole thread spun in.
This pilot attempted the equivalent of a turn back, though, with lots of power. All other things about what this pilot attempted were the same, as could be foolishly attempted after an engine failure close to the ground after takeoff. Low speed and altitude, and, 180 degree heading change in a small radius. This pilot intended this turn, and the only surprise (as opposed to a sudden engine failure) was that the aircraft simply was not capable of this, in the space available.
If, the pilot had not stalled and dropped the wing, at the altitude he did, he surly would have arrived at the water stalled, with no ability to arrest his rate of descent. There was just no lift or energy left in the aircraft. Had the plane been very light, and lots of power had been applied, things might have turned out better, but still, maybe not....
The left wing dropped, perhaps because it stalled, or perhaps due to a whole bunch of power being added, causing torque, which the lift of the wing, and aileron (with co-ordinated use of the rudder, of course) could not counteract.
This stall was destined to happen at just about the point where the pilot entered the left turn. The pilot forgot how much drag increase there would be with the turn, made worse by the very small radius of the turn (brought about by the choice to turn in such a confined area).
This video clearly demonstrates several things:
A wing can drop during a stall - but we knew that...
Turns cause lots of drag increase.
An attempt to land from a non stabilized approach can turn out badly,
And, the impossible turn. There was some discussion about the impossible turn recently in another thread on the instructors forum, but the whole thread spun in.
This pilot attempted the equivalent of a turn back, though, with lots of power. All other things about what this pilot attempted were the same, as could be foolishly attempted after an engine failure close to the ground after takeoff. Low speed and altitude, and, 180 degree heading change in a small radius. This pilot intended this turn, and the only surprise (as opposed to a sudden engine failure) was that the aircraft simply was not capable of this, in the space available.
If, the pilot had not stalled and dropped the wing, at the altitude he did, he surly would have arrived at the water stalled, with no ability to arrest his rate of descent. There was just no lift or energy left in the aircraft. Had the plane been very light, and lots of power had been applied, things might have turned out better, but still, maybe not....
The left wing dropped, perhaps because it stalled, or perhaps due to a whole bunch of power being added, causing torque, which the lift of the wing, and aileron (with co-ordinated use of the rudder, of course) could not counteract.
Join Date: Dec 1999
Location: Oop North, UK
Posts: 3,076
Likes: 0
Received 0 Likes
on
0 Posts
Pilot DAR - Link does not seem to work, hopefully this will:-
Float Plane Takes A Nose Dive! - YouTube
Float Plane Takes A Nose Dive! - YouTube
