Originally Posted by GearDown&Locked
If the crew sensed they were facing an imminent catastrophe why didn’t they throw everything out, using brute force like the parking brake? Doesn't come to mind in this type trainning?
Use of the Parking brake is the last-ditch effort, if all other brake systems fail. It is part of the "Loss of Braking" memory item:
[... failure of autobrake, manual normal brake, manual alternate brake ...]
IF STILL NO BRAKING
- PARKING BRAKE ............ USE
Use short successive parking brake applications to stop the aircraft. [...]
But you don't do that unless all other braking systems have failed. There is no indication that normal mode manual braking (with anti-skid) did not work.
The parking brake is not designed to decelerate the aircraft, it has no anti-skid, it cannot be modulated, it has a fixed brake pressure, and it may brake asymmetrically, causing a yawing moment.
Most importantly, it will provide less deceleration than the normal or alternate brakes.