Stall

Power on Stall Develops Into a Spin

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• published: 19 Dec 2012
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You've got to expect things are going to go wrong. And we always need to prepare ourselves for handling the unexpected. — Neil Armstrong, 2005 movie Magnificent Desolation: Walking On The Moon. This was a practice power on stall exercise with a student in a Cessna 172 (180HP STC). Notice aircraft is yawing left due to lack of right rudder. When the left wing drops the student attempted recovery by trying to lift the down wing with aileron (a very natural yet incorrect response) , this only aggravates the stall (by further increasing the wings AOA, and more deeply stalling the wing) and the development of a spin begins as we go into the vertical. The correct response to a wing drop is quick and pronounced opposite rudder. In 15 seconds we went from 7600ft MSL to 6600ft MSL before recovering. The descent was 4000ft a minute! We leveled off at 2100ft AGL and would have had only an additional 30 seconds before impact. The student goes hands off as I go hands on. We were able to recover after only half a turn (incipient phase) so the spin never fully developed. While pointed in the vertical directly at the ground I will tell you I had to mentally force myself to release the back pressure on the yoke. The urge to keep the yoke fully aft was very strong. As soon as I applied opposite right rudder the rotation stopped (again we were in the incipient phase so the rudder had a ton of authority still, this would not have been the case had the spin fully developed). It was an intense experience where training I received over a year ago suddenly kicked in. I am very thankful to my CFI spin instructor, Marcus Paine, and the great aerobatic instructors at Chandler Air Service, for preparing me to handle this situation which I was told would eventually happen. A pilot who wants to train out the natural response to lift a wing with aileron should practice the falling leaf exercise with a CFI.