The operator must select at least two destination alternate aerodromes for each IFR flight and specify them in the OFP when-
- the appropriate weather reports or forecasts for the destination aerodrome, or any combination thereof, indicate that during a period commencing one hour before and ending one hour after the estimated time of arrival, the weather conditions will be below the applicable planning minima; or
- meteorological information is not available at the destination aerodrome.