SAE ARP 503H PDF 2025

This SAE Aerospace Recommended Practice (ARP) provides criteria for design and location of power supplies, controls, light fixtures, and associated equipment which are used to provide emergency illumination in transport aircraft, designed to comply with 14 CFR Part 25 (see Reference 1) for operation under 14 CFR Part 91 (see Reference 11) and 14 CFR Part 121 (see Reference 2), and also in compliance with FAA Advisory Circulars AC 25.812-1A (see Reference 3) and AC 25.812-2 (see Reference 10).
It is not the purpose of an ARP to specify design methods to be followed in the accomplishment of the stated objectives.