The throttle handle is on the right lever. In the closed position it completely shuts the fuel regulator valve, stopping fuel from reaching the engine. Turning the handle counterclockwise, the pilot increases the engine thrust. During servicing of the pack with compressed nitrogen the handle is held in the closed position with a shear pin for safety. The pilot's timer is on the same handle. Since the pack has fuel for only for 21 seconds of flight, it is critical to know when the pack will run out of fuel, so that the pilot can safely land before his tanks are empty.