Originally Posted by
DAL4EVER
Its been awhile but I will try and draw on my old 737 knowledge. There is a small tube looking device that is right below the gear well. If it gets cut for any reason it is supposed to relieve hydraulic pressure
You got it right.....if you want to get technical, the systems term for it is "the Frangible Impact Fitting". The little shear pin/button is right on the ring of the main gear well and theoretically, a spinning wheel with a seperated tread hits the fitting causing all 'UP' hydraulic pressure to be dumped and the gear freefalls back down.