A few times in 30 years of flying.
1st time I was still a student. I found stalls to be a bit uneventful, they pretty much did what I expected them to. So I was out trying all kinds of stalls (solo) I finally tried a full flap power on stall and launched the plane up (very nose high). It promptly rolled over into about a 1/2 turn of a spin (looked like I was pointed straight down) I recovered promptly a pulled a couple G’s doing so. Two lessons learned . 1. It recovers a lot quicker, easier, and with less G’s if you pull the power off for the recovery ( I didn’t). 2. C-152’s ( and I later learned most other plans) have more aggressive stall characteristics with full flaps.
2nd time was in my glider I was landing off airport into a field the approach end was a couple hunderd feet higher than my touch down area so turning final I was only a about 200 feet above the ground instead of my normal 400 feet. The glider started to rumble (1-26 rumble) indicating it was near stall. I noted my airspeed was slow and lowered the nose. Moments later as I was evaluating my landing area the 1-26 rumbled again and an airspeed check again indicated I was slow and and pushed forward. I then watch my airspeed closely and noted that to maintain speed I had to watch the airspeed and forceably keep the nose down, If took my attention away from the airspeed for even a little bit I would slow down. This felt exactly like the lean’s when instrument flying where you feel like you are turning, so you start turning unless you force yourself to correct based on the instruments. In this case I felt like I was going fast since I was closer to the ground than normal giving the sensation of speed, causing me to slow down if I didn’t watch the instruments. I have since had a least two other pilots describe experiencing this phenomenon. Lesson learned. I think many stall spin accidents are the result of the false sensation (illusion) of speed and or ground track of the aircraft.
2 other times really weren’t inadvertent for me as I saw them coming, but the students I was flying with did not.
I used to instruct in a particular champ that on two occasions while doing slow flying the wing started to drop, the student tried pick up the wing with aileron and the wing dropped even more . This happened quite slowly in this champ. As the wing continued to drop the student(s) started adding back elevator until they had full opposite aileron and full back elevator as the plane slowly enter a spin. In both cases the student yelled something like “what do I do”, and my response was “push the stick forward”. When they did the ailerons started working and the plane came right out of the spin (No rudder required, but recommended) Lesson learned, you probably won’t recover from a stall spin if you aren’t thinking you could be in a stall spin situation.
Brian
CFIIG/ASEL