Brakes!!
Ref Missed Apch post #23.
I remember many years ago we DID indeed frequently use flaps as brakes, but with the advent of larger aircraft with greater wingspan and consequently more complex flap mechanisms this is no longer the case. I recall one well known aircraft manufacturer sending out a letter asking us to treat the mechanism with respect because of this complexity, telling us that they were strong enough, but continued such use would put unnecessary strain on the works.
Indeed, small amounts of flap can tend to make the aircraft more ‘slippery’, quite the opposite of braking, and it is not until one has greater than T/O flap that major drag comes into play.
Prober