if in flight you 'break' the flaps they don't stay extended. Airflow over them causes them to blow to trail...meaning they just retract.
I've had one flap snap back up thanks to a broken cable in a C-172. Was on a real high final with my usual 20º of flaps like 99% of landings, thought I was too high and added in 30 to make the second turnoff. As soon as the motor started, a nice loud BANG. Didn't take a rocket scientest to figure out what happened thanks to the a hefty roll to the right. Retracted the flaps, went around and landed no flaps.
I wasn't exceeding any speeds either, was at 70kts when I put in the extra 10 degrees and showing 4 whites on the PAPI.