Radio communications for remote pilots: CTAF, UNICOM and phraseology

Remote pilots are not required to talk on aviation radio, and should not transmit on aviation frequencies except in an emergency. But listening is one of the best ways to know what manned aircraft are doing near your site, and the test checks that you understand what you hear.

Frequencies at airports without a tower

Pilots at non-towered airports announce their positions on the common traffic advisory frequency (CTAF). The CTAF can be a UNICOM, MULTICOM, flight service or part-time tower frequency.

• UNICOM is often 122.8. It is also used for airport services such as fuel.
• If there is no tower, flight service or UNICOM, pilots use MULTICOM 122.9.
• Find the CTAF on the sectional (the frequency followed by a circled C) or in the Chart Supplement.

Inbound pilots usually report about 10 miles out, and say the airport name at the start and end of each call so listeners know which airport they mean.

ATIS

At larger airports the Automatic Terminal Information Service is a continuous recording of weather, active runway and other non-control information. It is updated at least hourly and each version gets a new letter: "information Bravo".

Phraseology

Aviation uses the ICAO phonetic alphabet: Alpha, Bravo, Charlie, Delta and so on. Numbers are spoken digit by digit, and 9 is said "niner". Altitudes are spoken in thousands and hundreds: 4,500 is "four thousand five hundred".

Call signs follow patterns:

• A light aircraft N123AB might call itself "Cessna One Two Three Alpha Bravo", shortened after first contact.
• Airlines use their company name and flight number, such as "Southwest Seven Eleven".

Traffic is described by clock position: "traffic two o'clock" is ahead and to the right.

Why listening matters

If you hear an aircraft report entering the downwind for the runway next to your site, you know where it will turn. A handheld receiver, a printed CTAF and a quick look at the traffic pattern direction on the chart are simple ways to stay ahead of manned traffic.