B737-200 Flap extension during flare
I have seen a couple of videos of B737-200 landings and there is something I don't understand. As far as I know an aircraft should be landed using a stabilized approach, no change of aircraft configuration below 500' or 1000' AAL. But in this landings the crew made a final flap extension (I think from 30 to 40) just during flare, before touchdown and after closing the throttles.
Is an approved technique?
Please, I would like som help with that