Guidance for Powered-Lift Electric Propulsion System Lightning Hazard Assessments
Year: 2026
Type: conference-paper
Abstract: The rapid development of powered-lift aircraft introduces novel electric propulsion systems lacking established service histories in lightning environments. To ensure flight safety applicants will show compliance with the airworthiness criteria outlined in FAA AC 21.17-4 (Type Certification Powered-Lift). This will ensure that these aircraft are safeguarded against catastrophic vehicle-level effects as well as hazardous or major propeller-level effects resulting from lightning strikes. This paper provides comprehensive guidance for conducting a Lightning Hazard Assessment (LHA) explicitly tailored to powered-lift electric propulsion systems. Applying the methodology outlined in SAE ARP5577 (Aircraft Lightning Direct Effects Certification), this assessment evaluates the direct effects of lightning attachment and current transfer on the structural and mechanical elements of the propulsion unit. By defining a simplified propulsion unit architecture, this paper traces expected current conduction paths from the propulsor blades through the hub, motor shaft, bearings, and motor controller down to the airframe. Furthermore, it details potential failure mechanisms for critical components, including resistive heating and acoustic shock damage in composite blades, arcing and pitting at metallic bearing interfaces, dielectric breakdown of internal motor insulation, and injected transients affecting sensitive power electronics. The assessment also accounts for novel operational scenarios inherent to these vehicles, such as distributed electric propulsion and vectored thrust tilt mechanisms. Ultimately, this paper highlights critical verification strategies—primarily laboratory testing—and continuing airworthiness considerations, such as post-strike inspections, essential for ensuring the long-term safety and reliability of powered-lift electric propulsion systems.
Authors: Ahmad, Faisal, Marple, Murray
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214716698