1.1 This specification covers minimum requirements for the design of Electric Propulsion Units (EPU).

1.2 Distributed propulsion is not excluded; however, additional requirements will be needed to address the additional issues that distributed propulsion can create. Some of those issues may include: use of a common motor controller/inverter, segregated electric harnesses, cooling systems, electric power supplies, and others.

1.3 This specification does not address all of the requirements that may be necessary for possible hybrid configurations where an EPU and a combustion engine drive a common thruster. This specification may be used for the EPU aspects with supplemental requirements for the thruster and the combustion engine.

1.4 This specification does not include the requirements for EPUs that include gearboxes, thrusters, liquid cooling/lubrication, or any energy storage systems. This specification may be used for the EPU base aspects with supplemental requirements for these additional features. This version of this ASTM specification also does not address all of the requirements necessary for configurations of motor driven ducted-fans. It is anticipated that the fan would be subject to parts of 14 CFR 33 or CS-E and/or 14 CFR 35 or CS-P, or equivalent, in particular blade-off and bird strike. These would be conducted on the fan as a unit (including motor) rather than on motor or fan alone.

1.5 The applicant for a design approval shall seek the individual guida