How to use radios?
I know recent airliners have as many as three radio sets.
But only three!
One is always used for ACARS.
One is for ATC communication.
The other is for 121.5Mhz?
If so, how about company radio or ATIS?
Then I'm wondering if 121.5 should be monitored by every pilot at any time?
I do not think old single piston airplanes have only one radio, which should be used for ATC.
Thank you for any input!