This SAE Recommended Practice (ARP) is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances. The purpose of this document is to establish a guideline for the selection of prime movers for use in aircraft ground support equipment. This document is recommended for use by those engaged in the design, selection, or purchase of ground support equipment. This document is applicable to both four-stroke and two-stroke spark ignition and compression ignition engines.