StacksVerified U.S. regulatory reference

40 CFR §1031.50

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
The following standards apply to new turbofan or turbojet aircraft engines with rated output at or below 26.7 kN thrust that are installed in subsonic aircraft:
  1. (a)Smoke. Engines of a type or model for which the date of manufacture of the individual engine is on or after August 9, 1985 may not have a characteristic level for smoke number exceeding the lesser of 50 or the following value:
  2. (b)[Reserved]