In November 2023, I organised a talk for my local LAA Devon Strut (= Chapter) by British test pilot and businessman Air Commodore Dave Best. He came with impeccable credentials, having served in the Royal Air Force from 1979 to 2012. In September 1999 he became commanding officer of the Defense Evaluation and Research Agency's Empire Test Pilot School at Boscombe Down, England. In 2022 he founded SkyBoss Aerospace Ltd and runs commercial test flying. He is a Fellow of both the Royal Aeronautical Society and the Society of Experimental Test Pilots.
Towards the end of his entertaining masterclass he said that *if you are in trouble, go for overstressing the aircraft rather than exceeding Vne.* This is a very competent test pilot talking so we should take note. His argument was along the lines of “when you exceed Vne you are going into uncharted territory”. The aerodynamic loads on the airframe increase proportionately with the square of the increase in speed. Say you hit 175 mph when your Vne is 150, you will have exceeded Vne by 25 mph, which is an overspeed of 16.7%. But the aerodynamic loads have gone up by a staggering 36%. In contrast, if your G limit is +6 and you pull 7g, the increase is the same, at 16.7%. However, as the loads on the airframe in this case are linearly proportional, the extra load at 7g is still only 16.7%, less than half of that caused by the overspeed. So, if you are heading downwards with speed increasing, you should “pull” rather than exceed Vne, and give your airframe a thorough inspection after you land! Mike Mold Devon, UK
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