14 C.F.R. § 125.365 Alternate airport for departure.
Title 14 - Aeronautics and Space
(a) If the weather conditions at the airport of takeoff are below the landing minimums in the certificate holder's operations specifications for that airport, no person may release an airplane from that airport unless the flight release specifies an alternate airport located within the following distances from the airport of takeoff: (1) Airplanes having two engines. Not more than 1 hour from the departure airport at normal cruising speed in still air with one engine inoperative. (2) Airplanes having three or more engines. Not more than 2 hours from the departure airport at normal cruising speed in still air with one engine inoperative. (b) For the purposes of paragraph (a) of this section, the alternate airport weather conditions must meet the requirements of the certificate holder's operations specifications. (c) No person may release an airplane from an airport unless that person lists each required alternate airport in the flight release.
Title 14: Aeronautics and Space
PART 125—CERTIFICATION AND OPERATIONS: AIRPLANES HAVING A SEATING CAPACITY OF 20 OR MORE PASSENGERS OR A MAXIMUM PAYLOAD CAPACITY OF 6,000 POUNDS OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT
Subpart K—Flight Release Rules
§ 125.365 Alternate airport for departure.
