second situation.?if the aircraft lands and the brake system did not work at allcan parking brakes used if the aircraft brake system failed?specially to large aircraftlike boeing and airbus???like in cars.if the brake system lost.there is a optionparking brake(handbrake)can this situation apply to the aircraft.?
In case of emergency where brakes and/or reverse thrust have failed - applying the parking brake is an option on some heavy aircraft. Obviously this would be used as an absolute last resort, given the high probablity of structural damage to the aircraft.
Large airliners also have what is called Reverse thrust How it works on the aircraft varies. On the MD 80 and 90 series two bucket looking things pop out from the engine and attenuate the thrust so that it faces forward. on the 737 the cowling hmm I dont know exactly how it works but it looks like the cowling slides apart a little bit which does the same thing which is to change the direction of the thrust. this is used to slow the aircraft down upon landing. As far as when a plane is parked at the gate they use wheel chocks. and the Parking brake does not have to be set. I think (aka I am not sure) that when the mechanics change a tire when a plane is a the gate the brakes are not set. the plane is being held in place with the chocks But to answer your question aircraft braking systems are vastly different than braking systems on a car. its hard to draw many parralels. I suppose if you had a monstously long runway you might be able to run an aircraft out especially if it was a smaller aircraft and had a slower landing speed. but without brakes you are in a world of hurt.
On large aircraft, the brake systems are hydraulic. The 747 has 4 seperate hydraulic systems, the brakes work on 2 of these seperate systems. If you have lost both of these systems you have got much bigger worries than the brakes working. But to answer your question, no they won't work on the parking brake. Light aircraft have a cable going from the parkbrake straight to the brake pedals so if the brakes aren't working the park brake won't work.
