This AC applies to certain sections of Title 14 of the Code of Federal Regulations (14 CFR) parts 21, 33, and 45, and describes or references methods of compliance that may be acceptable for engine type certification work.

This advisory circular (AC) provides guidance and acceptable means, but not the only means, for demonstrating compliance with the specific requirements applicable to 30-second and 2-minute One-Engine-Inoperative (OEI) rotorcraft turbine engine ratings in part 33 of Title 14 of the Code of Federal Regulations (14 CFR part 33).

This guidance is for the comparative test and analysis method used to show compliance to the airworthiness requirements under test and computation, per § 21.303 of Title 14 of the Code of Federal Regulations(14 CFR). This method supports showing the engine or APU still complies with 14 CFR part 33 and Technical Standard Order (TSO) C77.

This advisory circular (AC) provides guidance to support the development of technical data needed to show that an engine or APU replacement part complies with the airworthiness requirements under test and computation, per Title 14, Code of Federal Regulations (14 CFR) 21.303, using the comparative test and analysis approach. This guidance also supports the development of technical data needed for major repairs performed in accordance with 14 CFR Part 43.13(b), where parts fabrication and their implementation must be accomplished “in such a manner that the condition of the aircraft engine or appliance worked on will be at least equal to its original or properly altered condition.