Originally Posted by
squib
No ADG on any airplane drops while on the ground. Nice try though. They only drop in flight with the loss of all AC power. With your logic it would drop every time airplane is completely shut down for the night.
Battery master switch should always be off while on ground power without the APU running in the event ground power is pulled or fails and no one is on the airplane to prevent draining the batteries.
Originally Posted by
Tippy
ADG drops if all power is lost IF parking break is dropped and last source of AC power was INTERNAL. So if the plane was powered down wrong and left in chocks the ADG will drop. Urban legend that a ramper was pulling the cord and the parking break was off and the ramper was impaled by the ADG.
So yes it can happen, that's y parking brake is on the safety check before powering up anything
The ADG used to drop on the ground on a regular basis. SKW had bombardier add the parking brake to the logic, so it should never drop with the brake on.
I still am very careful about the power-down sequence because I'm not sure if the logic comes from the position of the brake handle or from the actual "PARKING BRAKE ON" bit. The bit is only set when the brakes are actually pressurized so it's possible to have the handle set but no brakes or advisory message if the hydraulics are off...and you turn the hydraulics off during the terminating flow.
Same reason you may not get the acars out time when you drop the brake if the 3B pump is off.
Also...I don't know if the brake being in the logic is just a SKW thing, or if all CRJs have been modified. Don't assume this is true at other airliners.
Never leave the plane powered with the battery off, that's a MX (and ramp) procedure only. If you find the airplane powered make sure the battery is on before you go fly. I don't think it will give you any cautions on that.
The ADG couldn't impale anyone, but it could cut you pretty good or give you a nasty bruise.