Section 121.621 - Alternate airport for destination: Flag operations(a) No person may dispatch an airplane under IFR or over-the-top unless he lists at least one alternate airport for each destination airport in the dispatch release, unless-(1) The flight is scheduled for not more than 6 hours and, for at least 1 hour before and 1 hour after the estimated time of arrival at the destination airport, the appropriate weather reports or forecasts, or any combination of them, indicate the ceiling will be: (i) At least 1,500 feet above the lowest circling MDA, if a circling approach is required and authorized for that airport; or(ii) At least 1,500 feet above the lowest published instrument approach minimum or 2,000 feet above the airport elevation, whichever is greater; and(iii) The visibility at that airport will be at least 3 miles, or 2 miles more than the lowest applicable visibility minimums, whichever is greater, for the instrument approach procedures to be used at the destination airport; or(2) The flight is over a route approved without an available alternate airport for a particular destination airport and the airplane has enough fuel to meet the requirements of § 121.641(b) or § 121.645(c) .(b) For the purposes of paragraph (a) of this section, the weather conditions at the alternate airport must meet the requirements of the certificate holder's operations specifications.(c) No person may dispatch a flight unless he lists each required alternate airport in the dispatch release.Doc. No. 6258, 29 FR 19222, Dec. 31, 1964, as amended by Amdt. 121-159, 45 FR 41594, June 19, 1980; Amdt. 121-253, 61 FR 2614, Jan. 26, 1996