Abstract: This invention relates generally to hydraulic and electrical systems for aircraft belt loaders and more particularly to such systems with interlocks to facilitate efficient and safe operation. The present invention provides a hydraulic and electrical system for battery powered aircraft belt loaders which precludes actuation of the electric traction drive motors when the brake is applied or set, or without the operator seat being occupied, which precludes actuation of the belt conveyor if the brake is not set, which controls conveyor run time and requires that the conveyor be reset to neutral before being actuated the hydraulic pump to permit power steering when the operator seat is occupied, and which requires that the directional control lever for traction drive be reset to neutral after demounting the seat before the electric traction drive motors can be energized.