OBJECTIVES:
- Explain how communication frequencies are used
- Explain GUARD
A special frequency that everybody should know is the emergency frequency: 121.500 Mhz, also called GUARD.
Note: For military operations it will be 243.000
GUARD is the emergency frequency worldwide and it has to be used for emergencies only.
Therefore the GUARD frequency should not be used for co-ordinations, nor activation/deactivation messages. There are the chat windows or the ATC channel instead.
An emergency exists from the moment the pilot has declared it.
Transmission on the GUARD frequency shall normally be initiated by the pilot. If there is an ATC critical situation where safety is endangered (virtually of course, but if you want it as real as it gets) controllers could use Guard as well.
Controllers could use Guard only if:
no other system works (chat, private msg, voice).
In all other cases, the Guard frequency is considered to be a pilot’s emergency frequency.
Note : In text mode, every controller/pilot connected can see your message if COM is set on 121.500.