Widely used in turbo-prop and business jets, Variable Frequency (VF) Electrical Power Systems are beginning to gain acceptance in the aviation industry. Commercial jet aviation manufacturers and systems integrators are interested because of the potential cost and weight savings VF systems offer. However, compatibility with conventional utility equipment that operates on 400Hz, fixed frequency (FF) still remains an issue in converting to VF power.This paper addresses considerations for the use of VF power in aircraft electrical power systems. It primarily identifies some of the difficult areas associated in the conversion over to VF using legacy equipment. The paper also provides the results of testing and modeling, and suggests alternate system configurations in adapting utilization equipment for VF use.