{"data":{"id":"us/14-cfr-121.509","jurisdiction":"us","citation":"14 CFR 121.509","heading":"Flight time limitations: Four pilot crews: airplanes.","body":"(a) No certificate holder conducting supplemental operations may schedule a pilot—\n(1) For flight deck duty in an airplane that has a crew of four pilots for more than eight hours in any 24 consecutive hours; or\n(2) To be aloft in an airplane that has a crew of four pilots for more than 16 hours in any 24 consecutive hours.\n(b) No pilot of an airplane that has a crew of four pilots may be on duty for more than 20 hours in any 24 consecutive hours.","path":["Title 14—Aeronautics and Space","CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER G—AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS","PART 121—OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS","Subpart S—Flight Time Limitations: Supplemental Operations"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-14.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:20Z","sha256":"eba065c28b46f8dd1d2f6c41e7deb127e868759416450a05cf7ccc32a5838846","source_id":"us-cfr","stale":true,"prev":"us/14-cfr-121.507","next":"us/14-cfr-121.511"},"notice":"GroundRules: Original legal text. Not legal advice."}