Question

(AIM)

All aircraft operating in US national airspace are highly encouraged to maintain a listening watch on VHF/UHF guard frequencies (____ or ____ MHz).

Answer 1

All aircraft operating in US national airspace are highly encouraged to maintain a listening watch on VHF/UHF guard frequencies (121.5 MHz or 243 MHz).

Step-by-step explanation:

All aircraft operating in US national airspace are highly encouraged to maintain a listening watch on VHF/UHF guard frequencies. The VHF guard frequency is 121.5 MHz, while the UHF guard frequency is 243 MHz. These frequencies are designated for emergency communication and can be used by aircraft to send distress signals or communicate with air traffic control during an emergency.

It is called guard because everybody is supposed to listen/guard the frequency just in case someone has a problem. Guard definitions: a state of caution, vigilance, or preparedness against adverse circumstances. watch over in order to protect or control.

Frequency 121.5 MHz, also known as the guard frequency, is a frequency reserved for civil aviation emergencies by the FAA. On the other hand, emergencies in military aviation are more often channeled through the 243 MHz frequency even though the 121.5 MHz can sometimes be used for similar purposes.