Authority
ASTM
Applicability
Design and installation of electric propulsion systems for aeroplanes; hybrid-electric systems are addressed implicitly unless otherwise stated. Broader use requires project-specific substantiation and authority acceptance.
Status
Active ASTM revision
Plain-English Explainer
ASTM F3239/F3239M-26 addresses airworthiness requirements for design and installation of aircraft electric-propulsion systems, with hybrid-electric systems included implicitly unless the standard says otherwise.
ASTM explicitly states that an applicant proposing the standard as a means of compliance must work with the relevant civil aviation authority on acceptable use and application.
ASTM's current edition is the 2026 revision. The FAA's Part 23 accepted-means-of-compliance page, effective May 2025, cites F3239-22a for specific powerplant provisions. A newer ASTM revision therefore should not be assumed to be automatically accepted in place of the revision listed by the FAA.
