40 CFR 1031.1: Applicability.

This part applies to aircraft gas turbine engines on and after January 1, 2023. Emission standards apply as described in subpart B of this part.

(a) Except as provided in paragraph (b) of this section, the regulations of this part apply to aircraft engines subject to 14 CFR part 33.

(b) The requirements of this part do not apply to the following aircraft engines:

(1) Reciprocating engines (including engines used in ultralight aircraft).

(2) Turboshaft engines such as those used in helicopters.

(3) Engines used only in aircraft that are not airplanes.

(4) Engines not used for propulsion.