Abstract: A variable power conveyance apparatus for propelling loads under environments where the angle of inclination of a conveyance path may change. For these apparatuses, in particular, those located in aircraft cargo bays, drive units are constructed to drive heavy loads under all conditions, including up a slope. These drive units may be organized into sets for loading pallets into and out of the aircraft and along the left and right storage tracks within fore and aft sections of the aircraft. An inclinometer senses the aircraft's angle of inclination and generates a representative electronic signal. Control logic determines whether to apply, via an SCR circuit, a minimum voltage or a greater variable voltage if the selected set of drive units is called upon to drive the pallets up a slope.