stall warner on landing
Thread Starter
Join Date: Dec 2004
Location: Asia
Age: 39
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
stall warner on landing
Just flew with a Swiss chap in Switzerland who tells me that the Swiss regard it to be absolutely essential that the stall warning sounds during the flare to touch down.
I was told in earnest that this was also the preferred method for a short field landing, i.e. shallow final approach (never mind the 50' obstacle), long flare, all just to get that cherished music.
Without the warner sounding, no landing is considered adequate, no student will be sent solo and candidates fail the GFT.
Any comments?
I was told in earnest that this was also the preferred method for a short field landing, i.e. shallow final approach (never mind the 50' obstacle), long flare, all just to get that cherished music.
Without the warner sounding, no landing is considered adequate, no student will be sent solo and candidates fail the GFT.
Any comments?
Last edited by WrongWayCorrigan; 9th Jun 2005 at 11:05.
Join Date: Feb 2005
Location: essex
Posts: 412
Likes: 0
Received 0 Likes
on
0 Posts
Sounds about right to me for normal conditions
Objective is to stop flying, wing stops flying once it is stalled, stall warner sounds a few knots before the stall (5 in most light aircraft)
Any excess speed will mean prolonged flare to loose excess
But..... Obviously not true in strong gusty wind conditions !
Objective is to stop flying, wing stops flying once it is stalled, stall warner sounds a few knots before the stall (5 in most light aircraft)
Any excess speed will mean prolonged flare to loose excess
But..... Obviously not true in strong gusty wind conditions !
Join Date: Nov 1999
Location: The Land Downunder
Posts: 765
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like a load of rubbish to me. For a start most of the years that I spent instructing there was a better than average chance that the stall warner wouldn't work at all, so saying that a student wouldn't go solo or pass gft's because the stall warner didn't go off on landing sounds a bit harsh. Not to mention that a shallow approach and long flare on a short field is asking for trouble in a big way.
Join Date: Apr 2004
Location: UK
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
"I was told in earnest that this was also the preferred method for a short field landing, i.e. shallow final approach (never mind the 50' obstacle)"
Slightly off topic, but why would a short field landing involve a shallow approach? Perhaps my relative inexperience is catching up on me and I need to get somebody in right hand seat again.
ThX
Slightly off topic, but why would a short field landing involve a shallow approach? Perhaps my relative inexperience is catching up on me and I need to get somebody in right hand seat again.
ThX
Join Date: Nov 2003
Location: notts
Posts: 636
Likes: 0
Received 0 Likes
on
0 Posts
Landing with a flop
You should land at the speed where the pilot still has effective controls beyond that which will be available at the stall all be it that the stall warner should be set to be activated between 5-12kts before the main wing stalls. On a normal landing it is unlikely that the stall warner is activated. Indeed for the aircraft CofA airtest a check is to note that it is NOT activated. I would imagine this particular Swiss Instructor is responsible for a lot of nose leg maintenance as in some types it will come crashing down unexspectedly as pitch authority is lost and no doubt will lead to some very tired main gear when the hold off is a touch too high.
As to the idea that a low slow approach produces a shorter landing is wrong although I know often taught. On an earlier thread a contributor proved the physics that the steeper an approach the shorter the landing distance. The correct approach speed is the most important element.
As to the idea that a low slow approach produces a shorter landing is wrong although I know often taught. On an earlier thread a contributor proved the physics that the steeper an approach the shorter the landing distance. The correct approach speed is the most important element.
Thread Starter
Join Date: Dec 2004
Location: Asia
Age: 39
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
stall warners on landing
To me, insisting on this is a total irrelevance, a focus on all the wrong things.
In a normal landing who cares if the stall warner sounds? Main thing is right place, right speed and in control.
A short field landing should involve a steep descent at a given airspeed over the nominal obstacle, minimum or no flare and braking to come to a halt within the shortest distance.
Poncing around just to get a stall warner going is i.m.h.o. totally daft.
In a normal landing who cares if the stall warner sounds? Main thing is right place, right speed and in control.
A short field landing should involve a steep descent at a given airspeed over the nominal obstacle, minimum or no flare and braking to come to a halt within the shortest distance.
Poncing around just to get a stall warner going is i.m.h.o. totally daft.
Join Date: Jan 2003
Location: The Heart
Posts: 811
Likes: 0
Received 0 Likes
on
0 Posts
A matter of definition regards short field landing' and 'short landing in a field'.
A short field landing is your strip technique assuming you have obstacles at the approach end. Thus, a steep approach is made to make use of as much of the field as possible, as close to the obstacle as possible.
A landing in a short field, known as a precautionary landing, assumes that you have selected a good field where the only unknown is the actual surface condition. Here you want the shortest possible ground roll at exactly the spot you have selected to touch down on.
Nothing wrong with requiring the stall warning to be activated at touchdown; it shows that the speed was controlled acurately and that isn't a bad thing to learn. Bearing in mind all landing data is based on the correct approach speed leading into the correct moment of power reduction and flare to the right attitude for touchdown.
Where there is little accuracy for the stall warning, I perhaps, wouldn't require it for every landing, it is a good indicator that the correct technique is being used.
You're never going to lose elevator authority at this point without a tailstrike first and that doesn't mean the nose will hit the ground that hard anyway.
The main gear is also much more able to cope with the strain.
I'd also like to take issue with the above method of short field landing. Minimum or no flare is v. bad advice. The key to a good short field landing (or any landing for that matter) is accurate speed control. Your technique implies that braking is the best way of stopping. It isn't if you have a taildragger, it isn't if you're on wet grass, and it isn't if you break the nose wheel which isn't designed for this treatment, and it isn't if you haven't got rid of all the lift the wings can produce (due to higher touchdown speed).
Once down you want to put as much weight on the mains as possible.
A short field landing is your strip technique assuming you have obstacles at the approach end. Thus, a steep approach is made to make use of as much of the field as possible, as close to the obstacle as possible.
A landing in a short field, known as a precautionary landing, assumes that you have selected a good field where the only unknown is the actual surface condition. Here you want the shortest possible ground roll at exactly the spot you have selected to touch down on.
Nothing wrong with requiring the stall warning to be activated at touchdown; it shows that the speed was controlled acurately and that isn't a bad thing to learn. Bearing in mind all landing data is based on the correct approach speed leading into the correct moment of power reduction and flare to the right attitude for touchdown.
Where there is little accuracy for the stall warning, I perhaps, wouldn't require it for every landing, it is a good indicator that the correct technique is being used.
You're never going to lose elevator authority at this point without a tailstrike first and that doesn't mean the nose will hit the ground that hard anyway.
The main gear is also much more able to cope with the strain.
I'd also like to take issue with the above method of short field landing. Minimum or no flare is v. bad advice. The key to a good short field landing (or any landing for that matter) is accurate speed control. Your technique implies that braking is the best way of stopping. It isn't if you have a taildragger, it isn't if you're on wet grass, and it isn't if you break the nose wheel which isn't designed for this treatment, and it isn't if you haven't got rid of all the lift the wings can produce (due to higher touchdown speed).
Once down you want to put as much weight on the mains as possible.
Thread Starter
Join Date: Dec 2004
Location: Asia
Age: 39
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
stall warner
I wasn't about to reply to this as clearly The Heart is nowhere near The Brain.
1. I'm not saying it's not a good thing to teach, but rather that it shouldn't be taught as the main priority.
2. No one is advocating driving aeroplanes into the ground and smashing up nosewheels. Really!
1. I'm not saying it's not a good thing to teach, but rather that it shouldn't be taught as the main priority.
2. No one is advocating driving aeroplanes into the ground and smashing up nosewheels. Really!
Join Date: Nov 2003
Location: notts
Posts: 636
Likes: 0
Received 0 Likes
on
0 Posts
Flopping
wrongwaycorrigan
I don't think that you intended any such thing either. At some point some may wish as you have clearly intended to DEBATE on these threads and not simply argue a singular point of view.
A correctly flown approach dosn't need the added distraction of simply holding off and hanging on airborne until the stall warner is activated, which may be; a horn, light or even stick-shaker.
There are some commonly flown types different from say a Cessna that while a Flare in the old sense of the word may be executed perfectly they will very suddenly lose pitch authority such as the Piper Tomahawk and the Grumman AA5. A common fault with Tomahawk is that the nose will come down very firmly if held up too long and if any rudder input is maintained the wheel will make contact with the ground sideways on. Differently with the AA5 the nosewheel assembly is a simple U-shaped tube which on impact is a very effective spring. Any sudden impact will cause a very lively pitch skywards. As to the main gear even such dosile types as the Piper Cherokee series will, if held aloft too long, simply belly flop and whether the main gear/nose gear is tough or not, time will take its toll.
I don't think that you intended any such thing either. At some point some may wish as you have clearly intended to DEBATE on these threads and not simply argue a singular point of view.
A correctly flown approach dosn't need the added distraction of simply holding off and hanging on airborne until the stall warner is activated, which may be; a horn, light or even stick-shaker.
There are some commonly flown types different from say a Cessna that while a Flare in the old sense of the word may be executed perfectly they will very suddenly lose pitch authority such as the Piper Tomahawk and the Grumman AA5. A common fault with Tomahawk is that the nose will come down very firmly if held up too long and if any rudder input is maintained the wheel will make contact with the ground sideways on. Differently with the AA5 the nosewheel assembly is a simple U-shaped tube which on impact is a very effective spring. Any sudden impact will cause a very lively pitch skywards. As to the main gear even such dosile types as the Piper Cherokee series will, if held aloft too long, simply belly flop and whether the main gear/nose gear is tough or not, time will take its toll.
Join Date: Feb 2005
Location: essex
Posts: 412
Likes: 0
Received 0 Likes
on
0 Posts
Oh dear what a lot of differing "opinions" on a very simple subject
For the pedants out there
1 - Ever heard of 1.3 VSO
2 - Stall "warner" as an indication that you hit the right spot ! Not suggesting you hold off until you hear it (but you will if you get the speed right).
Stands back - expecting more trouble !
For the pedants out there
1 - Ever heard of 1.3 VSO
2 - Stall "warner" as an indication that you hit the right spot ! Not suggesting you hold off until you hear it (but you will if you get the speed right).
Stands back - expecting more trouble !
Join Date: May 2003
Location: Asia
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
For those 'pendants', 1.3Vs is a legal requirement to ensure pitch authority for the flare but you could conceiveably keep floating until you hear the stall warning on touchdown so I don't think you can use that argument for this question.
IMHO I think it's dangerous to land with the stall warning horn sounding for a normal landing. In a Cessna, the nose would be awful high, I would feel very uncomfortable and there would be a possibility of a tailstrike. For a short field landing I would accept it if it came on just prior to touchdown but of course there are other considerations regarding that technique. I would like to know what type of aircraft this Swiss chap flies.
IMHO I think it's dangerous to land with the stall warning horn sounding for a normal landing. In a Cessna, the nose would be awful high, I would feel very uncomfortable and there would be a possibility of a tailstrike. For a short field landing I would accept it if it came on just prior to touchdown but of course there are other considerations regarding that technique. I would like to know what type of aircraft this Swiss chap flies.
Join Date: Jan 2003
Location: The Heart
Posts: 811
Likes: 0
Received 0 Likes
on
0 Posts
I agree, Unfazed, I thought it was a simple subject too.
My precautionary landing technique was learnt in a Tiger Moth, no stall warner other than seeing the slats pop out. Three point attitude and held in the air with power until you reach the point you want to touchdown on. Close the throttle and a quick check on the stick to soften the actual touch and you're down and stopped in no time.
I did point out that stall warners vary in accuracy. There does seem to be some confusion as to where the aeroplane is at this point where the stall warner may or may not activate.
The approach should be flown, as stated at a figure close to 1.3 Vso but the throttle will be closed at a certain point and the aircraft flared to the landing attitude. Having closed the throttle and reduced the rate of descent you will find the speed has reduced. If you stall at 45 and have approached entered the flare at 60 you only have approximately 10 kts to the stall warning. And this at a height of an inch or so, not going to harm any undercarriage. That's not unreasonable, is it?
Not a requirement, as I have agreed, but certainly not unreasonable.
Corrigan, old boy, you'll have to explain what you mean by "little or no flare".
Sounds like driving it on to me and as I pointed out, there doesn't seem to be any good reason for it. Get 'em all the time at work, "Going low, on purpose.", "Speed high, on purpose."
"What purpose?" if I may enquire.
Huck,
Is it pedantic to fly an aircraft as it was designed to be flown and according to the data produced when the aircraft was tested?
Perhaps, you prefer to make up your own rules?
My precautionary landing technique was learnt in a Tiger Moth, no stall warner other than seeing the slats pop out. Three point attitude and held in the air with power until you reach the point you want to touchdown on. Close the throttle and a quick check on the stick to soften the actual touch and you're down and stopped in no time.
I did point out that stall warners vary in accuracy. There does seem to be some confusion as to where the aeroplane is at this point where the stall warner may or may not activate.
The approach should be flown, as stated at a figure close to 1.3 Vso but the throttle will be closed at a certain point and the aircraft flared to the landing attitude. Having closed the throttle and reduced the rate of descent you will find the speed has reduced. If you stall at 45 and have approached entered the flare at 60 you only have approximately 10 kts to the stall warning. And this at a height of an inch or so, not going to harm any undercarriage. That's not unreasonable, is it?
Not a requirement, as I have agreed, but certainly not unreasonable.
Corrigan, old boy, you'll have to explain what you mean by "little or no flare".
Sounds like driving it on to me and as I pointed out, there doesn't seem to be any good reason for it. Get 'em all the time at work, "Going low, on purpose.", "Speed high, on purpose."
"What purpose?" if I may enquire.
Huck,
Is it pedantic to fly an aircraft as it was designed to be flown and according to the data produced when the aircraft was tested?
Perhaps, you prefer to make up your own rules?
Join Date: May 2003
Location: Asia
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
Miserlou, I agree with you. Fly the aircraft as it is designed to be flown. But is it normal for the stall warning to come on during touchdown? I personally don't think so and I don't think it's designed to do so either. I've never heard it during a normal landing in a Cessna except on gusty days when it will come on intermittently. As for making up my own rules, no I don't.
Join Date: Feb 2005
Location: essex
Posts: 412
Likes: 0
Received 0 Likes
on
0 Posts
"I've never heard it during a normal landing in a Cessna" (stall warner)
Huck old chap you need to try harder !
Picture the scene somewhere in Blighty - mid summer - smell of grass cuttings and aviation oil - nil wind and only fairweather cu to colour the scene.....all enhanced further by the sound of the stall warner congratulating you on your textbook Cessna landing !!
Come on give it a try and loose some of that excess airspeed
Huck old chap you need to try harder !
Picture the scene somewhere in Blighty - mid summer - smell of grass cuttings and aviation oil - nil wind and only fairweather cu to colour the scene.....all enhanced further by the sound of the stall warner congratulating you on your textbook Cessna landing !!
Come on give it a try and loose some of that excess airspeed
Join Date: May 2003
Location: Asia
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
Ahh, nice scene. But can I change the location to a place called Ardmore? I mentioned I've never heard it during a normal landing... didn't mention about my other less than 'normal' ones. Haha.
Why do it if it's not fun?
Join Date: Jul 2001
Location: Bournemouth
Posts: 4,779
Likes: 0
Received 0 Likes
on
0 Posts
Forgive me for barging in so late in the discussion, but it seems to me that all the "Yes" and "No" answers must surely be wrong?
Different stall warners, as Miserlou has said, have different sensitivities. One C150 I fly has a stall warner which used to sometimes goes off just after the aircraft enters a clean power-off stall at altitude, for example. This was clearly a fault with the stall warner on that particular aircraft, but demonstrates that not all stall warners on any given type of aircraft will go off at the same point.
So now, if we were to say that the stall warner must go off prior to landing, we would be faced with a situation where we could carry out a landing in one aircraft which, according to our criteria, would be perfectly acceptable. Then we could move to another aircraft, with a very slightly less sensitive stall warner, and carry out an identical landing (I know that no two landings are the same.....), yet by our own criteria this identical landing would be a bad one because the stall warner is configured differently? What crap!
Likewise, if we were to say that the stall warner must not go off before landing, we would be faced with the same problem, where a landing which was perfectly acceptable in one aircraft might not be acceptable if the stall warner was slightly more sensitive.
What do I look for in a landing? I teach my students to try to not land the aircraft, but to keep it flying for as long as they possibly can. This is the way I always try to land the aircraft myself, too. When I do what I consider to be a "good" landing in a C150/152/172/PA28, I run out of lift just as the wheels touch the ground. The nose wheel does not come crashing down when this happens; it actually makes a nice smooth landing. I have never had a tail-strike using this method either; I can't see how you could get a tail-strike unless you had left the power on for the flare (or, as happens more often with students, for a bounce recovery). Sometimes the stall warner goes off for this type of landing, more often it doesn't. I have never run out of elevator authority on landing, I just run out of lift. In fact, I often demonstrate to my students that I still have some elevator authority whilst taxying - move the controls forwards and backwards at about 20kts, and watch the nose go up and down. (Or point the aircraft into a 20kt wind whilst stationary on the ground and try the same thing.)
However, what is far more important in my opinion is what you do with the controls after the aircraft has landed. Anyone who lets go of the controls column after the aircraft has landed does not go solo in my aircraft, because it is that which causes the nose to come crashing down onto the ground after the main wheels. Once the main wheels have touched the ground, keep the controls back. Once the nose-wheel has touched the ground, keep the controls back. Keep the controls back until you have reached taxy speed - and even then you should really be keeping the controls back too, unless you have a strong tail-wind, but I tend to be a little more lenient at taxy speeds because in the aircraft I fly it's not so critical.
FFF
-----------------
Different stall warners, as Miserlou has said, have different sensitivities. One C150 I fly has a stall warner which used to sometimes goes off just after the aircraft enters a clean power-off stall at altitude, for example. This was clearly a fault with the stall warner on that particular aircraft, but demonstrates that not all stall warners on any given type of aircraft will go off at the same point.
So now, if we were to say that the stall warner must go off prior to landing, we would be faced with a situation where we could carry out a landing in one aircraft which, according to our criteria, would be perfectly acceptable. Then we could move to another aircraft, with a very slightly less sensitive stall warner, and carry out an identical landing (I know that no two landings are the same.....), yet by our own criteria this identical landing would be a bad one because the stall warner is configured differently? What crap!
Likewise, if we were to say that the stall warner must not go off before landing, we would be faced with the same problem, where a landing which was perfectly acceptable in one aircraft might not be acceptable if the stall warner was slightly more sensitive.
What do I look for in a landing? I teach my students to try to not land the aircraft, but to keep it flying for as long as they possibly can. This is the way I always try to land the aircraft myself, too. When I do what I consider to be a "good" landing in a C150/152/172/PA28, I run out of lift just as the wheels touch the ground. The nose wheel does not come crashing down when this happens; it actually makes a nice smooth landing. I have never had a tail-strike using this method either; I can't see how you could get a tail-strike unless you had left the power on for the flare (or, as happens more often with students, for a bounce recovery). Sometimes the stall warner goes off for this type of landing, more often it doesn't. I have never run out of elevator authority on landing, I just run out of lift. In fact, I often demonstrate to my students that I still have some elevator authority whilst taxying - move the controls forwards and backwards at about 20kts, and watch the nose go up and down. (Or point the aircraft into a 20kt wind whilst stationary on the ground and try the same thing.)
However, what is far more important in my opinion is what you do with the controls after the aircraft has landed. Anyone who lets go of the controls column after the aircraft has landed does not go solo in my aircraft, because it is that which causes the nose to come crashing down onto the ground after the main wheels. Once the main wheels have touched the ground, keep the controls back. Once the nose-wheel has touched the ground, keep the controls back. Keep the controls back until you have reached taxy speed - and even then you should really be keeping the controls back too, unless you have a strong tail-wind, but I tend to be a little more lenient at taxy speeds because in the aircraft I fly it's not so critical.
FFF
-----------------
Join Date: Mar 2002
Location: Euroland
Posts: 2,814
Likes: 0
Received 0 Likes
on
0 Posts
The stall speed is the minimum steady flight speed.
The stall warner is required to sound at some pre-determined speed above the stall.
If one runs out of elevator authority before reaching the stall speed, how can one stall the aircraft (1g) and demonstrate what the stall speed is?
If pilots are touching down close to the minimum flight speed then the stall warner should be sounding because holding the aircraft off at this speed will require an angle of atack close to the stall angle.
Perhaps if the speed is close to the stall at touchdown and the warner fails to sound then the stall warner is U/S and one must check to see if flight without the warner is permitted!
Best short landing figures are obtained from power off approach at the appropriate speed, flare, land and maximum braking. That is where Cessna get the numbers from.
Remember also that if one flares a bit quickly (more than 1g) than the stall speed will increase and not only will the stall happen at a higher speed (nose drop) but the warner will so at a higher speed also. This is also worth thinking about with regard to the nose wheel.
Regards,
DFC
The stall warner is required to sound at some pre-determined speed above the stall.
If one runs out of elevator authority before reaching the stall speed, how can one stall the aircraft (1g) and demonstrate what the stall speed is?
If pilots are touching down close to the minimum flight speed then the stall warner should be sounding because holding the aircraft off at this speed will require an angle of atack close to the stall angle.
Perhaps if the speed is close to the stall at touchdown and the warner fails to sound then the stall warner is U/S and one must check to see if flight without the warner is permitted!
Best short landing figures are obtained from power off approach at the appropriate speed, flare, land and maximum braking. That is where Cessna get the numbers from.
Remember also that if one flares a bit quickly (more than 1g) than the stall speed will increase and not only will the stall happen at a higher speed (nose drop) but the warner will so at a higher speed also. This is also worth thinking about with regard to the nose wheel.
Regards,
DFC
Join Date: Jan 2003
Location: The Heart
Posts: 811
Likes: 0
Received 0 Likes
on
0 Posts
So, we're all agreed then and can say without shadow of doubt or fear of contradiction, maybe!
FFF mentions a point which is particularly relevant when discussing the abuse of the undercarriage during landing.
Why do people give up flying the aircraft as soon as the main wheels are firmly planted?
FFF mentions a point which is particularly relevant when discussing the abuse of the undercarriage during landing.
Why do people give up flying the aircraft as soon as the main wheels are firmly planted?
The Cessna 172 POH has a table headed Landing Distance - Short Field. The speed used to attain the distances quoted is in fact the "normal" approach speed based on certification tests - ie 1.3 VS. The Boeing 737 "normal" approach speed for normal landings is the equivalent in principle to the Cessna figures.
In no case does the pilot deliberately reduce the approach speed below the stated "normal" approach speed as stated in the flight manuals (POH if you like). Therefore in reality the so called short field landing is always a normal landing speed and technique in order to attain the book landing distance figures.
During the war real short field landings required a certain speed reduction below the certification speed - usually 10% or even 20% lower. Landing on an aircraft carrier is an example of this where the approach is made at 1.1Vs instead of the normal 1.3Vs. (those figures are not necessarily correct but you get the idea, I hope). In those cases, it was slipstream provided by the propeller that kept the inboard wing area from stalling and if you chopped the power before the flare you would certainly fall out of the sky. Thus the true "short field" landing certainly required a powered approach "hanging on the prop" and of course as soon as the aircraft was flared the float would be minimal and the subsequent landing roll short. Just the sort of technique needed to land an aircraft into a field of unknown length but assuming the worst - very very short. Military trainee pilots were taught this technique until proved competent. These were not normal 1.3Vs landings that we know nowadays.
It wasn't until Flight Manuals were produced for civilian aircraft that certification requirements demanded a min speed of 1.3Vs for calculation of landing distances. Again there were probable exceptions to the method of stall speed calculation for purposes of landing speeds "over the fence".
All this boils down to there is no such thing as a short field landing where an approach speed significantly below the certification speed in the POH is routinely used. Thus if the POH speed is used correctly, then there will always be a float period to dissipate the speed (light aircraft such as Cessna types) before touch-down. That is because it is not the done thing to "plant" an aircraft on all three wheels at flying speed. There are obvious dangers to this - nose-wheel damage - bounce - and application of non-anti-skid brakes at relatively high ground speed.
If your instructor demands an approach at less than the POH recommended approach speed (1.3Vs) then it is both illegal and reckless. It is never done in a airliner or business jet, so why should it be done in a trainer?
In no case does the pilot deliberately reduce the approach speed below the stated "normal" approach speed as stated in the flight manuals (POH if you like). Therefore in reality the so called short field landing is always a normal landing speed and technique in order to attain the book landing distance figures.
During the war real short field landings required a certain speed reduction below the certification speed - usually 10% or even 20% lower. Landing on an aircraft carrier is an example of this where the approach is made at 1.1Vs instead of the normal 1.3Vs. (those figures are not necessarily correct but you get the idea, I hope). In those cases, it was slipstream provided by the propeller that kept the inboard wing area from stalling and if you chopped the power before the flare you would certainly fall out of the sky. Thus the true "short field" landing certainly required a powered approach "hanging on the prop" and of course as soon as the aircraft was flared the float would be minimal and the subsequent landing roll short. Just the sort of technique needed to land an aircraft into a field of unknown length but assuming the worst - very very short. Military trainee pilots were taught this technique until proved competent. These were not normal 1.3Vs landings that we know nowadays.
It wasn't until Flight Manuals were produced for civilian aircraft that certification requirements demanded a min speed of 1.3Vs for calculation of landing distances. Again there were probable exceptions to the method of stall speed calculation for purposes of landing speeds "over the fence".
All this boils down to there is no such thing as a short field landing where an approach speed significantly below the certification speed in the POH is routinely used. Thus if the POH speed is used correctly, then there will always be a float period to dissipate the speed (light aircraft such as Cessna types) before touch-down. That is because it is not the done thing to "plant" an aircraft on all three wheels at flying speed. There are obvious dangers to this - nose-wheel damage - bounce - and application of non-anti-skid brakes at relatively high ground speed.
If your instructor demands an approach at less than the POH recommended approach speed (1.3Vs) then it is both illegal and reckless. It is never done in a airliner or business jet, so why should it be done in a trainer?