When you check the emergency extension of the gear, first retract the gear normally, secure external hydraulic pressure, place the landing gear handle in the down position, and then pull and hold the emergency extension handle fully aft. Visually check that all gear assemblies are down and locked by observing the landing gear position indicator in the cockpit, and then release the emergency extension handle. The force required to push the main gear to the locked position should not exceed 20 pounds applied to the axle hub. The force required to push the nose gear to the locked position should not exceed 10 pounds applied at the center line of the axle hub. Make at least one complete normal cycle of the landing gear, and then remove external power and aircraft from jacks.
Some aircraft require resetting of the landing gear dump valves before recycling the landing gear.
Refer to the applicable MIMs. Troubleshooting steps provided in the MIM are normally aligned with the sequence of events or steps in the operational checkouts. They provide an efficient means of isolating the malfunction. The MIM requires that each step in the operational checkouts be performed in sequence. If trouble occurs during the procedure, it must be corrected before proceeding with the next step.