{"data":{"id":"us/40-cfr-1031.40","jurisdiction":"us","citation":"40 CFR 1031.40","heading":"Turboprop engines.","body":"The following standards apply to turboprop engines with rated output at or above 1,000 kW:\n(a) Smoke. Engines of a type or model for which the date of manufacture of the individual engine is on or after January 1, 1984, may not have a characteristic level for smoke number exceeding the following value:\nSN = 187·rO− 0.168\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":"03334dbe7bc5130cc7e04662316238b5121632e3e25439459513a85471bce654","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1031.30","next":"us/40-cfr-1031.50"},"notice":"GroundRules: Original legal text. Not legal advice."}