Using CTAF and Monitoring ATC
CTAF stands for Common Traffic Advisory Frequency — the specific radio frequency pilots use to self-announce their position and intentions at a non-towered airport, using exactly the phraseology structure explained in the previous lesson. This lesson explains what CTAF is, how to find it, and how a remote pilot who chooses to monitor it — listening without necessarily transmitting — builds real, actionable situational awareness that supports 14 CFR 107.37's right-of-way rule and 14 CFR 107.43's no-interference rule.
What CTAF actually is
A Common Traffic Advisory Frequency is a designated radio frequency, published for a specific non-towered airport, that pilots use to broadcast their position and intentions to everyone else operating at or near that airport — a shared "party line" where every pilot both transmits their own updates and listens for everyone else's. Because there's no control tower actively managing traffic at a non-towered airport, CTAF is the mechanism that lets pilots build a shared mental picture of who else is where, using the standardized phraseology structure covered in the previous lesson.
Where to find a specific airport's CTAF frequency
An airport's CTAF frequency is published information, most commonly found printed directly on a sectional chart near the airport's symbol — typically shown as a frequency number preceded by the letters "CT," positioned close to the airport data block. The same frequency is also listed in the FAA's Chart Supplement (a reference publication covering airport-specific information) and in most third-party aviation apps and airport information databases. A remote pilot planning an operation near a non-towered airport can identify the correct CTAF before ever arriving on site, the same way they'd identify the runway orientation covered in the previous lesson.
CTAF is sometimes also the tower frequency, used differently after hours
Some airports have a control tower that doesn't operate 24 hours a day. During the tower's operating hours, that airport functions as a towered field with ATC actively sequencing traffic; outside those hours, the same frequency the tower used during the day often becomes the CTAF, and pilots self-announce on it exactly as they would at a fully non-towered airport. Recognizing this distinction matters because the same airport, and the same frequency, can function completely differently depending on the time of day.
Monitoring versus transmitting: what a remote pilot actually needs to do
For most Part 107 operations, the relevant activity on CTAF is monitoring — listening to the frequency to hear what manned traffic near your operating area is doing, without necessarily transmitting anything yourself. This is consistent with the earlier point that Part 107 doesn't require radio equipment at all; a remote pilot who does choose to bring a handheld aviation radio to a mission near a non-towered airport, purely to listen, gains real situational awareness value from doing so, even without ever keying the microphone.
A non-towered airport's CTAF frequency is printed directly on the sectional chart, preceded by the letters "CT," next to the airport symbol.
View LargerWorked scenario: CTAF monitoring during a real estate shoot
You're flying a real estate exterior shoot a half-mile from a non-towered airport. Before launching, you identify the airport's CTAF from a sectional chart and bring a handheld aviation radio set to that frequency. Partway through the mission, you hear a call: "Fairview traffic, Piper seven eight nine Delta Echo, ten miles northwest, inbound, Fairview traffic." Applying the position-report structure from the previous lesson, you now know an aircraft is approaching from the northwest, roughly ten miles out — information you can use to plan whether to continue, adjust your flight path, or pause the mission until that aircraft has landed, well before it becomes a right-of-way concern under 107.37.
What monitoring cannot tell you
CTAF monitoring is a valuable supplement to visual scanning, not a replacement for it. Not every aircraft near a non-towered airport transmits reliably or at all — some aircraft may have a malfunctioning or misconfigured radio, and pilots occasionally simply forget to announce. CTAF monitoring should be treated as one additional layer of situational awareness on top of, never instead of, the visual scanning and see-and-avoid discipline that remains the primary tool for satisfying 107.37's right-of-way requirement.
Monitoring at towered airports: a different frequency, a different purpose
At a towered airport, the relevant frequency to monitor is the tower's own frequency rather than a CTAF, since ATC is actively directing traffic there rather than pilots self-announcing. Monitoring the tower frequency near a towered airport lets a remote pilot hear the same kind of position and sequencing information, just relayed through the controller's instructions to various aircraft rather than through pilots announcing to each other directly.
Why this lesson doesn't describe transmitting a self-announcement on CTAF as standard practice
Unlike a manned aircraft in the pattern, a Part 107 sUAS operation isn't a traffic pattern participant in the same functional sense, and routinely transmitting sUAS position reports on CTAF isn't a standard, expected practice the way it is for a manned aircraft entering the pattern. The primary, broadly applicable use of CTAF for a Part 107 operation is monitoring for awareness; specific circumstances where actual transmission becomes relevant — including when an authorization's conditions call for it — are covered in the next and final lesson of this module.
| Element | Non-towered airport (CTAF) | Towered airport |
|---|---|---|
| Who uses the frequency | All pilots self-announcing to each other | ATC directing individual aircraft |
| How to find it | Sectional chart ("CT" plus frequency), Chart Supplement, aviation apps | Sectional chart tower frequency listing, aviation apps |
| Typical remote pilot use | Monitor for position reports from nearby traffic | Monitor ATC instructions to hear nearby traffic activity |
| Special case | — | A part-time tower's frequency often becomes the CTAF after hours |
Preparing to Monitor CTAF Before a Mission
Complete this during mission planning, before arriving on site.
Identify the nearest relevant airport and its status
Confirm whether it's towered, non-towered, or a part-time tower that may be closed during your mission window.
Find the correct frequency for your mission time
Look up the CTAF (or tower frequency, if operating during staffed hours) from a sectional chart, Chart Supplement, or aviation app.
Set a handheld aviation radio to the correct frequency, if using one
Confirm the radio is receiving clearly before launch — a radio with a dead battery or wrong frequency provides no actual awareness benefit.
Combine monitoring with active visual scanning throughout the flight
Treat radio monitoring as a supplement to, not a replacement for, watching for traffic that may not be transmitting.
Adjust your operation based on what you hear
Use overheard position reports to inform your own flight path, altitude, or timing decisions in support of 107.37 and 107.43 compliance.
| Mistake | Why it happens | Correct understanding | Regulation / source |
|---|---|---|---|
| Assuming CTAF is the same frequency at every airport | "CTAF" sounds like a single universal frequency rather than an airport-specific one | Each non-towered airport has its own published CTAF, which must be looked up individually. | FAA Remote Pilot Study Guide |
| Treating radio silence on CTAF as proof no other aircraft is nearby | An active, ongoing conversation would seem like the expected sign of traffic | Not every aircraft reliably announces; CTAF monitoring supplements, but never replaces, visual scanning. | 14 CFR 107.37 |
| Believing a part-time towered airport always uses the same procedures regardless of time of day | The airport's physical layout and tower don't visibly change based on hours | The same frequency can function as an active tower frequency during staffed hours and as a self-announce CTAF after hours. | FAA Remote Pilot Study Guide |
Is a remote pilot required to monitor CTAF near a non-towered airport?
No specific Part 107 regulation requires it. Monitoring CTAF is a recommended situational-awareness practice that supports compliance with 107.37 and 107.43, not a separate legal mandate on its own.
What does "CT" mean when printed next to a frequency on a sectional chart?
"CT" identifies the printed frequency as the airport's CTAF (Common Traffic Advisory Frequency), distinguishing it from other frequency information that might be printed nearby, like a tower or approach control frequency.
Can I use CTAF to transmit an announcement about my sUAS operation?
Nothing prohibits it, but it isn't standard, universally expected practice the way it is for manned aircraft in the pattern. The specific circumstances where direct communication becomes genuinely necessary or expected are covered in the next lesson.
Test Your Knowledge
Answer the questions below to check your understanding. Every answer can be found in the lesson above.