Very high frequency (VHF) 121.5 and ultra high frequency (UHF) 243.0 are “guarded” frequencies reserved in the aircraft operations band exclusively for emergency communications and notifications.
People Also Ask
As of 2009, the Cospas-Sarsat system terminated monitoring and reception of the 121.5 MHz and 243.0 MHz frequencies.
During the takeoff roll, the pilot monitoring the displays (PM) will call out the two important speeds: V1 and rotate. This indicates to the pilot flying the aircraft (PF) when they are beyond the safe stopping speed and when to rotate the aircraft into the air.
The most well know of these is the code 7700. This is used to indicate an emergency of any kind. A pilot will enter this when in an emergency situation - either instructed by ATC after declaring an emergency or without communication if there is no time.
The most popular is the 144-MHz (2-meter) band. That's where you'll find a lot of ham radio operators as well as local public safety calls. If you want to hear the civilian aircraft frequencies, you'll want to look for a radio that has the 118 to 136 MHz air band.