This document covers performance test methods of fuel cell power systems intended for being used to power unmanned aircrafts, including general requirements, start-up, shutdown, power output, continuous running time, electric efficiency, data transmission, warning and monitoring, environmental compatibility, etc. The scope of the document is limited to electric powered unmanned aircrafts with a maximum take-off mass not exceeding 150 kg (i.e., level 5 or lower UAs). The document applies to fuel cell power systems with a rated output voltage not exceeding 220 V DC for outdoor use. The document applies only to compressed gaseous hydrogen-fuelled fuel cell power systems. The document does not apply to reformer-equipped fuel cell power systems.