True short field landings
Thread Starter
True short field landings
Over the past year the subject of teaching short field landings that are required in various CASA publications came up for general discussion. The main comments were on what airspeed should be used as against what is generally taught at flying schools. The accepted technique is use the airspeed from the manufacturers POH that is recommended to meet the landing length tables. In the Cessna POH for the C150/C172 the tables are annotated Short Field Landing which is actually a misnomer. In other words the tabulated landing field lengths achievable if using the airspeed published.
Basically 1.3 times the stall speed in the landing configuration. For the Cessna 172N it is 59 knots IAS.
At that airspeed in order to touch down at the slowest speed some float is anticipated; thus using more runway. To try and "spike" the aircraft on to the runway for minimum ground roll is asking for trouble - meaning a series of kangaroo type bounces with the added danger of damaging the nose wheel.
Instructors talk about the desirability to minimise the float to achieve a minimum ground roll and that is true; but how can that happen when on the other hand there is bound to be some float due to nature of the airspeed of 1.3 Vs above actual touch down speed. So what Cessna short field landing" actually means, is nothing more than normal landing. It is the Cessna POH terminology that causes confusion and the fact that many instructors are apprehensive of reducing the airspeed "over the fence" to the POH figure. Most are concerned the students will mishandle airspeed control and teach them a higher speed.
Having said all that, readers may be interested in this accident report from BASIS (Google it if you haven't a clue what it means!) Journal No.4, Autumn 1989, concerning the sad end to an Auster at Point Cook, and note it was a real short field landing of the type taught at flying schools with reasonable safety in he old days.
Edited for brevity.
04 Dec, AUSTER 3F, VH-BCG, non-commercial - pleasure, POINT COOK VIC PPL 689 hours experience.
"The pilot had been practicing short field landings in light and variable wind conditions, using the 170 degree grass strip. He made an approach for a practice short field landing with full flap selected at an approach speed of 38 knots (stall speed in that configuration is 25 knots). The pilot said that as he approached the ground, the rate of descent was high so he let the airspeed increase to 40 knots to initiate the flare. Rate of descent was still to high so he applied power.
The aircraft landed in the three point attitude (the Auster is a tail wheel type). The pilot described the landing as heavier than he would have liked. The aircraft did not bounce but ran straight and then started to sag on the right side. The right main gear diagonal brace had broken and the remainder of the structure gradually bent under the weight of the aircraft. The pilot steered the aircraft off the grass to the right and stopped.
The broken diagonal brace was inspected and was found to have failed due to overload.
It was also determined that the pilot had not made many short field landings for some time. It was for that reason that he decided to practice a short field landing."
The Auster was used extensively by the RAF and Army Cooperation units during WW2 because of its excellent slow speed landing capability. Normal approach speed was around 45-50 knots. In the case of the accident aircraft the pilot reduced speed to 38 knots some 10 knots less than recommended approach speed. In those days this was normal procedure for many other Service aircraft that is knock off 10 knots from normal landing speed and thus reduce the float and subsequent landing roll.
Short field landings came with its risk of mis-handling especially in windy or crosswinds. Student pilots were warned of this and to be vigilant about not getting too slow on final and risking a stall.
These then were true short field landings and not the fake news so called short field landings taught by todays instructors directly from the manufactures POH.
Basically 1.3 times the stall speed in the landing configuration. For the Cessna 172N it is 59 knots IAS.
At that airspeed in order to touch down at the slowest speed some float is anticipated; thus using more runway. To try and "spike" the aircraft on to the runway for minimum ground roll is asking for trouble - meaning a series of kangaroo type bounces with the added danger of damaging the nose wheel.
Instructors talk about the desirability to minimise the float to achieve a minimum ground roll and that is true; but how can that happen when on the other hand there is bound to be some float due to nature of the airspeed of 1.3 Vs above actual touch down speed. So what Cessna short field landing" actually means, is nothing more than normal landing. It is the Cessna POH terminology that causes confusion and the fact that many instructors are apprehensive of reducing the airspeed "over the fence" to the POH figure. Most are concerned the students will mishandle airspeed control and teach them a higher speed.
Having said all that, readers may be interested in this accident report from BASIS (Google it if you haven't a clue what it means!) Journal No.4, Autumn 1989, concerning the sad end to an Auster at Point Cook, and note it was a real short field landing of the type taught at flying schools with reasonable safety in he old days.
Edited for brevity.
04 Dec, AUSTER 3F, VH-BCG, non-commercial - pleasure, POINT COOK VIC PPL 689 hours experience.
"The pilot had been practicing short field landings in light and variable wind conditions, using the 170 degree grass strip. He made an approach for a practice short field landing with full flap selected at an approach speed of 38 knots (stall speed in that configuration is 25 knots). The pilot said that as he approached the ground, the rate of descent was high so he let the airspeed increase to 40 knots to initiate the flare. Rate of descent was still to high so he applied power.
The aircraft landed in the three point attitude (the Auster is a tail wheel type). The pilot described the landing as heavier than he would have liked. The aircraft did not bounce but ran straight and then started to sag on the right side. The right main gear diagonal brace had broken and the remainder of the structure gradually bent under the weight of the aircraft. The pilot steered the aircraft off the grass to the right and stopped.
The broken diagonal brace was inspected and was found to have failed due to overload.
It was also determined that the pilot had not made many short field landings for some time. It was for that reason that he decided to practice a short field landing."
The Auster was used extensively by the RAF and Army Cooperation units during WW2 because of its excellent slow speed landing capability. Normal approach speed was around 45-50 knots. In the case of the accident aircraft the pilot reduced speed to 38 knots some 10 knots less than recommended approach speed. In those days this was normal procedure for many other Service aircraft that is knock off 10 knots from normal landing speed and thus reduce the float and subsequent landing roll.
Short field landings came with its risk of mis-handling especially in windy or crosswinds. Student pilots were warned of this and to be vigilant about not getting too slow on final and risking a stall.
These then were true short field landings and not the fake news so called short field landings taught by todays instructors directly from the manufactures POH.
Damn and blast these young people of today.
Moderator
Some thoughts, perhaps ...
(a) a particular aircraft will be certificated with whatever approach speed to 50ft. Come significantly below that and come to grief and you have some awkward questions to answer .. because you weren't supposed to be there.
(b) STOL is a military animal and involves takeoff and landing operation at speeds rather less than the normal civil certification requirements. The additional risk associated with a reduced speed pad is an accepted operational consideration. So, as a general observation, when we talk about "STOL" in respect of civil aircraft, we are talking through our hats somewhat and really are referring to operations at the minimum speeds. Just what minimum speeds .. well that can vary a bit according to the story teller.
(c) it is common practice, especially on light aircraft to approach at speeds a little above the AFM/POH book value(s), I guess to add a bit for inexperience, mum and the kids, and whatever else. Providing that the excess speed isn't so great as to cause undue float etc., and you have plenty of runway, no real problem. However, the legit minimum speed remains whatever the POH says it should it be .. go slower and prang, and you need a good story.
(d) we all are well aware that, in the good old days of yore, folks were a bit gamer and used approach speeds somewhat less than the book value .. just don't get caught out.
(e) 1.3 by 25 = 37.5, what am I missing?
What most folk miss when they try to do this sort of sum while not knowing what is required. The quoted end figures, presumably IAS, have whatever PEC involved. You need to convert the starting figure to CAS, do the sum, and then convert the answer back to IAS. Then you should get the answer sought. The report quoted in the earlier post doesn't have enough information to know just what they are talking about specifically.
Down in the stall region weeds, PEC can become a bit significant .. we all know that the little Cessnas can hang on the prop with nothing on the clock bar the maker's name .. but the "speed" indicated has little to do with reality, I'm afraid.
(a) a particular aircraft will be certificated with whatever approach speed to 50ft. Come significantly below that and come to grief and you have some awkward questions to answer .. because you weren't supposed to be there.
(b) STOL is a military animal and involves takeoff and landing operation at speeds rather less than the normal civil certification requirements. The additional risk associated with a reduced speed pad is an accepted operational consideration. So, as a general observation, when we talk about "STOL" in respect of civil aircraft, we are talking through our hats somewhat and really are referring to operations at the minimum speeds. Just what minimum speeds .. well that can vary a bit according to the story teller.
(c) it is common practice, especially on light aircraft to approach at speeds a little above the AFM/POH book value(s), I guess to add a bit for inexperience, mum and the kids, and whatever else. Providing that the excess speed isn't so great as to cause undue float etc., and you have plenty of runway, no real problem. However, the legit minimum speed remains whatever the POH says it should it be .. go slower and prang, and you need a good story.
(d) we all are well aware that, in the good old days of yore, folks were a bit gamer and used approach speeds somewhat less than the book value .. just don't get caught out.
(e) 1.3 by 25 = 37.5, what am I missing?
What most folk miss when they try to do this sort of sum while not knowing what is required. The quoted end figures, presumably IAS, have whatever PEC involved. You need to convert the starting figure to CAS, do the sum, and then convert the answer back to IAS. Then you should get the answer sought. The report quoted in the earlier post doesn't have enough information to know just what they are talking about specifically.
Down in the stall region weeds, PEC can become a bit significant .. we all know that the little Cessnas can hang on the prop with nothing on the clock bar the maker's name .. but the "speed" indicated has little to do with reality, I'm afraid.
I reckon it’s a good idea to practise slow flying in landing configuration at altitude. 3,000’ AMSL on a nice cool, high pressure day can be the same density altitude as 500’ on final to a sea level aerodrome on a hot, low pressure day.
I don’t think you can do a proper short-field landing unless you know the gentle hints as to when you’re aircraft will stall, in the real world.
I’m frequently surprised at how little runway I need to do a ‘normal’ landing in my ‘high performance’ bugsmasher, then watching subsequent landings in little Cessnas and Pipers coming in high and fast and using up most of the runway.
I don’t think you can do a proper short-field landing unless you know the gentle hints as to when you’re aircraft will stall, in the real world.
I’m frequently surprised at how little runway I need to do a ‘normal’ landing in my ‘high performance’ bugsmasher, then watching subsequent landings in little Cessnas and Pipers coming in high and fast and using up most of the runway.
Join Date: Nov 2005
Location: Zulu Time Zone
Posts: 730
Likes: 0
Received 0 Likes
on
0 Posts
By using the AFM figures you do not get the shortest possible ladding roll. What you get is an approach that will enable the ‘average pilot’ to most consistently reproduce the landing distance tabulated and also have a safe margin for a go around. If you are an Alaskan bush pilot flying fishermen onto sand bars you will probably have a different set of figures that you can make work due to your greater experience and familiarity with that type of operation. But not many flight schools are teaching Alaskan bush pilots. The average student does not even come with the ability of the average pilot.
I’m guessing that because you’re located in “GT’s Sex Dungeon” that you know all about “stick position”?
Join Date: Apr 2011
Location: Victoria
Posts: 750
Likes: 0
Received 0 Likes
on
0 Posts
Over the past year the subject of teaching short field landings that are required in various CASA publications came up for general discussion. The main comments were on what airspeed should be used as against what is generally taught at flying schools. The accepted technique is use the airspeed from the manufacturers POH that is recommended to meet the landing length tables. In the Cessna POH for the C150/C172 the tables are annotated Short Field Landing which is actually a misnomer. In other words the tabulated landing field lengths achievable if using the airspeed published.
Basically 1.3 times the stall speed in the landing configuration. For the Cessna 172N it is 59 knots IAS.
At that airspeed in order to touch down at the slowest speed some float is anticipated; thus using more runway. To try and "spike" the aircraft on to the runway for minimum ground roll is asking for trouble - meaning a series of kangaroo type bounces with the added danger of damaging the nose wheel.
Instructors talk about the desirability to minimise the float to achieve a minimum ground roll and that is true; but how can that happen when on the other hand there is bound to be some float due to nature of the airspeed of 1.3 Vs above actual touch down speed. So what Cessna short field landing" actually means, is nothing more than normal landing. It is the Cessna POH terminology that causes confusion and the fact that many instructors are apprehensive of reducing the airspeed "over the fence" to the POH figure. Most are concerned the students will mishandle airspeed control and teach them a higher speed.
Having said all that, readers may be interested in this accident report from BASIS (Google it if you haven't a clue what it means!) Journal No.4, Autumn 1989, concerning the sad end to an Auster at Point Cook, and note it was a real short field landing of the type taught at flying schools with reasonable safety in he old days.
Edited for brevity.
04 Dec, AUSTER 3F, VH-BCG, non-commercial - pleasure, POINT COOK VIC PPL 689 hours experience.
"The pilot had been practicing short field landings in light and variable wind conditions, using the 170 degree grass strip. He made an approach for a practice short field landing with full flap selected at an approach speed of 38 knots (stall speed in that configuration is 25 knots). The pilot said that as he approached the ground, the rate of descent was high so he let the airspeed increase to 40 knots to initiate the flare. Rate of descent was still to high so he applied power.
The aircraft landed in the three point attitude (the Auster is a tail wheel type). The pilot described the landing as heavier than he would have liked. The aircraft did not bounce but ran straight and then started to sag on the right side. The right main gear diagonal brace had broken and the remainder of the structure gradually bent under the weight of the aircraft. The pilot steered the aircraft off the grass to the right and stopped.
The broken diagonal brace was inspected and was found to have failed due to overload.
It was also determined that the pilot had not made many short field landings for some time. It was for that reason that he decided to practice a short field landing."
The Auster was used extensively by the RAF and Army Cooperation units during WW2 because of its excellent slow speed landing capability. Normal approach speed was around 45-50 knots. In the case of the accident aircraft the pilot reduced speed to 38 knots some 10 knots less than recommended approach speed. In those days this was normal procedure for many other Service aircraft that is knock off 10 knots from normal landing speed and thus reduce the float and subsequent landing roll.
Short field landings came with its risk of mis-handling especially in windy or crosswinds. Student pilots were warned of this and to be vigilant about not getting too slow on final and risking a stall.
These then were true short field landings and not the fake news so called short field landings taught by todays instructors directly from the manufactures POH.
Basically 1.3 times the stall speed in the landing configuration. For the Cessna 172N it is 59 knots IAS.
At that airspeed in order to touch down at the slowest speed some float is anticipated; thus using more runway. To try and "spike" the aircraft on to the runway for minimum ground roll is asking for trouble - meaning a series of kangaroo type bounces with the added danger of damaging the nose wheel.
Instructors talk about the desirability to minimise the float to achieve a minimum ground roll and that is true; but how can that happen when on the other hand there is bound to be some float due to nature of the airspeed of 1.3 Vs above actual touch down speed. So what Cessna short field landing" actually means, is nothing more than normal landing. It is the Cessna POH terminology that causes confusion and the fact that many instructors are apprehensive of reducing the airspeed "over the fence" to the POH figure. Most are concerned the students will mishandle airspeed control and teach them a higher speed.
Having said all that, readers may be interested in this accident report from BASIS (Google it if you haven't a clue what it means!) Journal No.4, Autumn 1989, concerning the sad end to an Auster at Point Cook, and note it was a real short field landing of the type taught at flying schools with reasonable safety in he old days.
Edited for brevity.
04 Dec, AUSTER 3F, VH-BCG, non-commercial - pleasure, POINT COOK VIC PPL 689 hours experience.
"The pilot had been practicing short field landings in light and variable wind conditions, using the 170 degree grass strip. He made an approach for a practice short field landing with full flap selected at an approach speed of 38 knots (stall speed in that configuration is 25 knots). The pilot said that as he approached the ground, the rate of descent was high so he let the airspeed increase to 40 knots to initiate the flare. Rate of descent was still to high so he applied power.
The aircraft landed in the three point attitude (the Auster is a tail wheel type). The pilot described the landing as heavier than he would have liked. The aircraft did not bounce but ran straight and then started to sag on the right side. The right main gear diagonal brace had broken and the remainder of the structure gradually bent under the weight of the aircraft. The pilot steered the aircraft off the grass to the right and stopped.
The broken diagonal brace was inspected and was found to have failed due to overload.
It was also determined that the pilot had not made many short field landings for some time. It was for that reason that he decided to practice a short field landing."
The Auster was used extensively by the RAF and Army Cooperation units during WW2 because of its excellent slow speed landing capability. Normal approach speed was around 45-50 knots. In the case of the accident aircraft the pilot reduced speed to 38 knots some 10 knots less than recommended approach speed. In those days this was normal procedure for many other Service aircraft that is knock off 10 knots from normal landing speed and thus reduce the float and subsequent landing roll.
Short field landings came with its risk of mis-handling especially in windy or crosswinds. Student pilots were warned of this and to be vigilant about not getting too slow on final and risking a stall.
These then were true short field landings and not the fake news so called short field landings taught by todays instructors directly from the manufactures POH.
Austers are an interesting beast and yes, you can land at extremely slow speeds.
My J5D has humongous flaps and stalls around 26 knots but I try not to rely on that because it is also susceptible to gusts and you are relying on a lot of power to get you down gently at such small margins. This is how the Army pilots used to do it.
I like to have 50 knots on the turn to final (VFE is 58) with at least one stage then pull 2 when I'm sure my glide will see me over the fence. I side slip if high and don't use 3 all that often unless close to nil wind. I try to put one wheel down first in a crosswind and always 3 point. Austers weren't built to main wheel but I'm happy to bow to Nick Caudwells vastly superior skills who happily dances the AUSTER from wheel to wheel down the runway and nails a wheeler every time.
500 hours on type and still learning.
Kaz
Join Date: Sep 2007
Location: Australia
Posts: 121
Likes: 0
Received 0 Likes
on
0 Posts
Why is that nobody ever mentions Flap Dumping during the flare (With manual flaps of course) when discussing "Short Landings"? Has to be done with skill and care, but it works really well as a method of putting the aeroplane exactly on the spot. Is it a taboo subject?
Join Date: Apr 1998
Location: Mesopotamos
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
During my training I found short field landings to be much more comfortable, more fun and easier than your normal mushy landing using your regular training hack. Simply set the correct attitude and tractor her in controlling the ROD with throttle - how easy can that be.
I vividly remember during my PPL flight test when the examiner ask me to do a short field landing touching down on the runway numbers, my response was at the top or the bottom of the numbers, he didn't reply.
I vividly remember during my PPL flight test when the examiner ask me to do a short field landing touching down on the runway numbers, my response was at the top or the bottom of the numbers, he didn't reply.
Join Date: Jul 2006
Location: Australia
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
A mate of mine did a "short field" landing in his Jabiru. The front "snapped" off and he and his pax stepped out where the windscreen once was :-). You certainly do need to be careful.
You certainly do need to be careful.
In my case No 10 Squadron at Townsville flew its Lincolns, Wirraway and a Dakota in the display. I was supposed to demo a short field landing in a Long Nose Lincoln in front of spectators at Garbutt Airfield (Townsville).
On the day I decided (much to my later chagrin) to knock off a few knots below the normal landing speed in order to plant it on the threshold.
The old Lincoln fell out of the sky from 50 feet and being a tail wheel type, it bounced so high I had to go-around.
The noise of four Rolls Royce Merlins clawing for the sky at max power bought more cheers from the crowd than a smooth three-pointer would have done. They thought it was part of the act.
.
Two points seem to have been missed.
It's 1.3 Vs at 50 feet, not 1.3 to the flare. An approach flown accurately with speed decreasing to 1.3 Vs at 50 feet and continuing to decrease to touchdown will result in a touchdown close to Vs and thus little or no float.
The Vs figure quoted in the POH is at MAUW. When used for training your average C172 and PA28 is most likely well below it's MAUW and so the Vs in that situation is going to be less. The Vs of 59 KIAS for the C172 mentioned about is actually higher than the Vs for a normal training situation. On the basis Vs changes at the square root of the load factor you can calculate the Vs for any given weight. You might be surprised at what the Vs is for a C172 with half tanks and two up.
It's 1.3 Vs at 50 feet, not 1.3 to the flare. An approach flown accurately with speed decreasing to 1.3 Vs at 50 feet and continuing to decrease to touchdown will result in a touchdown close to Vs and thus little or no float.
The Vs figure quoted in the POH is at MAUW. When used for training your average C172 and PA28 is most likely well below it's MAUW and so the Vs in that situation is going to be less. The Vs of 59 KIAS for the C172 mentioned about is actually higher than the Vs for a normal training situation. On the basis Vs changes at the square root of the load factor you can calculate the Vs for any given weight. You might be surprised at what the Vs is for a C172 with half tanks and two up.
Last edited by 27/09; 9th Feb 2018 at 23:14.
Moderator
The Vs figure quoted in the POH is at MAUW.
Depends on the POH performance section. The better documents will have more data and schedule the speeds/distances according to the weight.
Interestingly, if the approach speed is solely for MLW, the landing distance required usually then increases with decreasing weight, largely due to the increased float .. but it saves dollars in the work up side of things for the OEM or subsequent modifier.
Small bugbear of mine, I'm afraid ..
Depends on the POH performance section. The better documents will have more data and schedule the speeds/distances according to the weight.
Interestingly, if the approach speed is solely for MLW, the landing distance required usually then increases with decreasing weight, largely due to the increased float .. but it saves dollars in the work up side of things for the OEM or subsequent modifier.
Small bugbear of mine, I'm afraid ..