{"data":{"id":"us/40-cfr-1031.50","jurisdiction":"us","citation":"40 CFR 1031.50","heading":"Subsonic turbojet and turbofan engines at or below 26.7 kN thrust.","body":"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:\n(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:\nSN = 83.6·rO− 0.274\n(b) [Reserved]","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER U—AIR POLLUTION CONTROLS","PART 1031—CONTROL OF AIR POLLUTION FROM AIRCRAFT ENGINES","Subpart B—Emission Standards and Measurement Procedures"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"9af1f77af14facc1e83f9693138505ab63b471be9b3deaf757ecb3a8edd60cfd","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1031.40","next":"us/40-cfr-1031.60"},"notice":"GroundRules: Original legal text. Not legal advice."}