14 CFR 121.599 : Aeronautics And Space (§ 1.1 To Parts 1311-1399) — (§ 110.1 To Part 199) — Federal Aviation Administration, Department Of Transportation (Continued) (§ 110.1 To Part 199) — Air Carriers And Operators For Compensation Or Hire: Certification And Operations (§ 110.1 To § 139.343) — Operating Requirements: Domestic, Flag, And Supplemental Operations (§ 121.1 To Appendix P To Part 121) — Dispatching And Flight Release Rules (§ 121.591 To § 121.667) — Familiarity with weather conditions.

4 Aug 2016

(a) Domestic and flag operations. No aircraft dispatcher may release a flight unless he is thoroughly familiar with reported and forecast weather conditions on the route to be flown.

(b) Supplemental operations. No pilot in command may begin a flight unless he is thoroughly familiar with reported and forecast weather conditions on the route to be flown.

14 CFR 121.599
[Doc. No. 6258, 29 FR 19222, Dec. 31, 1964, as amended by Amdt. 121-253, 61 FR 2614, Jan. 26, 1996]