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.
