mixturerichlean
About 9 months ago I was a passenger in a C172 - we were a little high on approach so the pilot, on 20 degrees flap, selected full flaps (30 degrees) on short finals. At about 400 - 500 ft coming in to land the picture of the approach appeared that we would need some more power to take us to the threshold. Instead of adding power the pilot reduced flaps to 20 degrees which flattened the approach and we landed on the keys with no extra input of power.
It was the first time I had seen this technique and wondered if this was acceptable (ie safe) and wondered what might the pitfalls be if this practice is not safe.
I wonder if the OP or anyone else has considered that maybe this pilot was just practising a glide approach after simulating an engine failure downwind, that would make the above procedure a perfectly normal technique to obtain the correct touchdown point on your runway, or an off airport landing in a field, personally I practice glide approaches regularly for this reason.