GMIA - 121.5MHz - Int'l Emergency Aircraft frequency

[rc1990]

I've been in Moncton for about a month. I've heard the Int'l Emergency Aviation frequency (121.5) being active quite a few times. However, none of those time, it was use for an emergency (I hear normal calm ATC tranmissions)! Would it be use for some other purpose (like as a back-up freq for the tower)? I thought that freq was to be use ONLY in an emergency!

 

[kma371]

This has come up before. Sometimes pilots listen to 121.5 on a back up radio for emergencies.

When they key up on the primary radio for normal ATC comms, it activates both. And that's why you hear them.

I'm sure others have different theories.

 

[WA1ATA]

Could the transmissions be the first VHF contact with transoceanic flights that don't have an assigned Vhf freq?

121.5 is not just for emergencies. It is also used to contact aircraft that for any reason are no longer in contact with ATC on the regular freq.

 

[rc1990]

Thanks guys!