CHOCK one up for AAL…
What can happen if ground crew doesn’t chock the wheels.
Wouldn’t a parking brake stop that? And the parking brake is in the checklist?
flightglobal.com/articles/20 … -on-a.html
Because the investigation is still ongoing, American does not know the exact cause of the incident. The airline says it is unsure if the brakes were set and malfunctioned, or if the brakes were not set at all. The Dallas-based carrier does confirm, however, that the wheels were not chocked at the time of the incident.
I may need some correcting by someone more familiar with the bird…but once systems are shut down, arent the parking brakes pretty much null and void, hence the necessity for chocks?
The parking brake is hydraulically controlled. The engines maintain hydraulic pressure, but only when the engines are on.
Somebody in the ground crew was too fat, and leaned against the plane. . . 
The parking brake is hydraulically actuated.
Park Brake control is mechanical or electrical.
The engine or aux Hydraulic pumps provide the pressure. The park brake traps the pressure and allows you to shut down the engines/apu leaving the brake set. If the system isn’t tight pressure can bleed down over time, thats when the chocks are wanted.
I bet the brake was never set.
+1.
The parking brake is hydraulically actuated.
Park Brake control is mechanical or electrical.
The engine or aux Hydraulic pumps provide the pressure. The park brake traps the pressure and allows you to shut down the engines/apu leaving the brake set. If the system isn’t tight pressure can bleed down over time, thats when the chocks are wanted.
I bet the brake was never set.
+1