I am not an instructor, however....
The essential components of a spin are wings stalled with yaw and/or roll present. Deliberately inducing yaw with rudder to “pick up” a dropped wing, with the aircraft stalled, is tantamount to setting up for a spin.
Very much agreed!
A number of times, while deliberately stalling aircraft for test purposes (the aircraft, not the pilot), other pilots who have accompanied me have resisted the use of ailerons to maintain co-ordinated flight up to the stall. Though a few aircraft (C 208 Caravan for example) recommend minimizing the use of ailerons during a stall recovery, the certification requirements state that the aircraft must be recoverable with "normal" use of the controls. For certified general aviation aircraft types, great use of ailerons (or rudder) during a stall will increase drag, and perhaps worsen the situation just a little,
gentle use of the ailerons will not cause the aircraft to spin - great use of the rudder will!
"oscillatory stalling"
Will occur with certain very stall resistant aircraft types. The most pronounced example of this I have seen is a Robertson STOL equipped C 206 with 40 flap extended. Though the aircraft will indicate all of the symptoms of a stall, and be descending at a high rate, it can be flown at yet a slower indicated airspeed. This occurs becasue the aircraft with lots of up elevator applied will bob up and down, with a corresponding increase and decrease in indicated airspeed, but you cannot control it. You can recover any time you like, but you cannot maintain a speed slower than the faster speed then that at which you entered. The aircraft only reaches this speed momentarily on its own, then speeds up again. Of course, the whole time you're doing this, the stall warning is screaming, and you're going down at a heck of a rate.
During flight testing of this type, I had a heck of a time defining the "stall speed" in KIAS. I was told by the flight test authority that the
fastest indicated speed at which pitch control could not be maintained was the stall speed. The fact that the aircraft could be flown at yet a slower speed, albeit with this "bobbing" in pitch, did not give credit for a slower speed. Stall speeds are predicated on the speed at which the pilot can no longer maintain pitch control (one of the criteria). At a slower speed, that condition has already occurred, even if the plane is oscillating between these speeds on its own.