PLT2427

IPH IFR Alternate Requirments 1-14Not all airports can be used as alternate airports. An airport may not be qualified for alternate use if the airport NAVAID is unmonitored, or if it does not have weather reporting capabilities.

ICAO Annex 10, Vol 2. Chaper 5 Aeronautical Mobile Service - Voice Communications5.1.5 Recommendation.--- After a call has been made to the aeronautical station, a period of at least 10 seconds should elapse before a second call is made. This should eliminate unnecessary transmissions while the aeronautical station is getting ready to reply to the initial call.