Here's a schoolboy practical explanation once demonstrated by a very respectable Boeing Flight Operations Engineer and never since forgotten:
- Pretend you are the aircraft and your hands are the brakes;
- On landing, you apply brakes, so clap your hands and push them together for 30 seconds;
- After landing you taxi to the parking position, so clap your hands twice to resemble stopping/slowing down on your way to there;
- Having reached the parking position you set brakes to park, so clap your hands one last time and keep them pressed together;
- Once chocks are in place, parking brake can be released, so after some 15 seconds of pressing hands together, move them apart and FEEL the effect this action has on your palms: THAT'S WHY we release brakes to cool them.
Clap & hold [30 seconds], clap, clap, clap & hold [15 seconds], release...
