The hydraulic system is controlled by an electrically driven hydraulic pump which operates the retractable landing gear, tailwheel, and flaps. There is a hand-operated hydraulic pump attached to the floor of the cockpit on the right side. On models through the P-40 L, there is an additional hand-operated hydraulic pump inboard of the main hydraulic pump. This is an emergency pump, not an auxiliary pump. Use ft only in an emergency. Operate by removing pump handle from regular, or outboard, pump and attaching it to the emergency, or inboard, PUMP. To check the functioning of the hydraulic system on the ground: 1. Place the flap handle DOWN. This allows the flaps to drop 100 to 150. 2. Put the flap handle in UP and pump up the flaps with the hard hydraulic pump untill you build up a solid pressure.