One destination alternate for IFR flight unless :
1) Duration of flight less than 6 hours (from take off to landing)
2) 2 separate runways available and useable at destination. Each runway should have its own approach procedure based on separate NAVAIDs.
3) Appropriate weather forecast at destination airport indicates that for 1 hour either side of ETA the ceiling will be 2000 ft or circling height + 500 ft > Whichever the greater
4) Visibility > 5 KM
- The destination is isolated and no adequate alternate exists
2 destination alternate aerodrome should be selected when weather report or forecasts indicate that for 1 hour either side of ETA, the weather at destination airport will be below planning minima or no meteorological information is available.