I heard this word while local flying, and can't find any other results on internet.

I only knew that 'monitoring a frequency' means only listenening to the selected frequency, rather than making a communication channel.

What is 'dual monitoring', and how is it different from 'monitoring a frequency'?

  • $\begingroup$ Further to the answer provided... It's a common practice among some aviators to always be monitoring COM2, since it's there for free anyway. Tuning it to the emergency freq, (121.50 in the US) and listening "just in case" is called being "on guard." Or if you are VFR in an area where there's approach control, you can dial that up and listen in. Also quite useful in IFR flight because you really need to stay on your controller's freq because you can go get ATIS, as the answer suggests. $\endgroup$
    – Max R
    Commented Aug 5, 2022 at 2:36

1 Answer 1


In an aircraft with two or more comm radios, you can only transmit on one, but you can listen to more than one frequency.

So "dual monitoring" this would be listening (and transmitting) on one frequescy, while also listening on a second frequency. This is common when you're in contact with one ATC, but maybe you're passing close to perhaps a busy airport where you might want to monitor their movements. Another good example is monitoring an ATIS while also talking to an approach controller.

This is a pretty standard radio panel in most light aircraft

enter image description here

The knob to the right selects which comm radio you transmit on. The button with illumination marked COM1 is which comm radios you're monitoring. You might usually have just COM1 selected, but you can also select COM2 (and/or COM3) to dual monitor. As you can see from the above image it is possible to have 3 comm radios wired to this box.


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