Work Item
ASTM WK83412

New Specification for Design of Hybrid-Electric Powerplants for General Aviation Aircraft

1. Scope

1.1 This specification covers minimum requirements for the design of hybrid-electric powerplants. Note: hybrid-electric powerplant will need to be defined. We can start with a basic definition of: “an aircraft engine that generates electrical power for use as primary aircraft propulsive power.” There is obviously much to be discussed on this point.

1.2 This specification is applicable to series-hybrid, parallel-hybrid, and series/parallel-hybrid configurations.

1.3 This specification is applicable to hybrid powerplants that utilize internal combustion engines as the prime mover, including turbine-hybrid, piston-hybrid, rotary-hybrid, or other internal combustion engine cycles and configurations.


generator; generation; APU; electric power


Part 33, a prescriptive regulation, does not include rules that govern hybrid-electric powerplants. Discussions with the FAA indicate that existing processes for certification of auxiliary power units (APUs) are not appropriate for hybrid powerplants. Existing ASTM and SAE standards mention hybrid power, but only as an aside; VerdeGo Aero is not aware of any existing standards efforts to develop a design standard for hybrid powerplants. The proposed standard will be used as a Means of Compliance to Part 33 and/or EASA CS-E for hybrid powerplants. Potential users are VerdeGo Aero, Rolls Royce, Raytheon/Pratt & Whitney/Collins, Honeywell, and any other company pursuing stand-alone certification of a hybrid powerplant.

The title and scope are in draft form and are under development within this ASTM Committee.


Developed by Subcommittee: F39.05

Committee: F39

Staff Manager: Joe Koury

Work Item Status

Date Initiated: 09-09-2022

Technical Contact: David Eichstedt

Item: 000