Originally Posted by
ecam
Interesting perspective, never thought of that.
The handful we fly without them do get hot brakes often, but they do seem to cool off faster too.
Yes, those things are obnoxiously loud.
Without the fans, the brake temps start to up, peak, and then decline on their own. They are open to the air. Convection conduction,,and radiation. Put the fans on and they hold the heat in. They start to get hot, keep getting hotter, and don't cool off until you turn the fans on. If you park at the gate and come back 2 hours later with the fans off, they still have a lot of residual heat.
3 years at UAL flying 319's and 320's with no fans, hot brakes maybe 5 or 6 times. 4 years at 2 airlines with 319,320, 321, I might have NOT gotten hot brakes the same number of times.