View all text of Subpart U [§ 121.591 - § 121.667]
§ 121.599 - Familiarity with weather conditions.
(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.