@bcgallacher:
Whoa, no need to lash out at people... One of those aircraft is the 777 - Gear extension only releases the uplocks hydraulically to let the gear free fall (metered by a flow restrictor in the retraction actuator). The side and drag braces on the main gears are also hydraulically overcentered to lock the gear down, but they will extend and lock without pressure as well during a manual extension. (Ref AMM 32-32-00-001)