HF, it sounds like that instructor was not thinking far enough ahead of the plane. From what you describe, that should have been seen as an approach to a possible spin, which, in a 172 (other than BoseX's apparently
) is permitted within limitations. But I recall one of those limitations being flaps up for spin entries.
Two reasons for this:
If you spin with flaps extended, it is very likely that you will exceed either or both of the flap limiting speed or G loading during the recovery, because you forget to retract, or the electric flaps won't retract fast enough.
Secondly, a spin entry is a sideslip. Most 172's are placarded to
avoid slips with flaps extended. Not prohibited, just avoid... But, the avoid is because in some slipping conditions, the wake off the outboard corner of the flap will impinge on the H tail on that side, and render it less effective. If you're trying to recover a spin, you'd like the H tail to be effective.
BoseX, the placard against spins for your 172... is it original from Cessna? Or perhaps associated with an STC'd mod (engine change or STOL kit)?