Frequencies

In aviation, frequencies refer to the specific radio channels used for communication between aircraft and air traffic services (ATS). These are typically found in the VHF (Very High Frequency) band and are standardized internationally to ensure clarity, compatibility, and safety.

• Aviation radio uses the range from 118.000 MHz to 136.975 MHz
• Each frequency is spaced in increments of 8.33 kHz
• Older aircraft may still use 25 kHz spacing (legacy), but 8.33 kHz spacing is mandatory in most European airspace
• Frequencies are always stated to three decimal places, but aircraft radios may only display two

• One frequency per sector or function to reduce congestion
• Ground stations may transfer control by handing over to a new frequency
• Pilots must ensure positive two-way contact when switching frequencies

• “Contact Wien Radar on one two four decimal four”
• “Remain on frequency, report when ready for departure”
• “Change to Salzburg Tower one one eight decimal one”
• “Monitor ATIS on one two six decimal zero three zero”

• Always say “decimal” to indicate the point
• Correct: “one two four decimal four”
• Incorrect: “one twenty-four point four”

• Emergency frequency: 121.500 MHz (monitored continuously by ATC and military)
• Guard frequency: Also 121.500, used for distress calls and lost comms
• Training frequencies: Sometimes allocated for school use, under regulation
• Military/UHF: Military often uses separate UHF ranges, not accessible via civilian VHF radios

• ✅ Always confirm a new frequency before switching
• ✅ Write down unfamiliar frequencies immediately
• ✅ Listen before transmitting (avoid blocking active transmissions)
• ✅ Use LearnATC to simulate real-world frequency changes and traffic handoffs