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Non-towered · Class G at the surface

Knox County (4I3) radio calls

Mount Vernon, OHFAA identifier 4I3; no ICAO code assigned

Knox County is a non-towered airport in Mount Vernon, OH. Nobody clears you to do anything: you self-announce on the CTAF, 123.05, as Knox County Traffic, with the airport name at the start and end of each call. The approach control for the area is Columbus Approach on 125.95, which is who you call for VFR flight following.

No Class B, C, D or E surface area is designated for this airport in the FAA data, so the airspace at the surface is Class G.

Frequencies

Clearance Delivery119.45
CTAFKnox County Traffic123.05
Approach / DepartureColumbus Approach125.95

Airport

Runways
10 · 28
Elevation
1,192 ft
Pattern altitude
808 ft MSL (published TPA)
Position
40.329, -82.526

Non-towered airport: self-announce on the CTAF

Sample calls at 4I3

Knox County has no operating control tower. Every call below goes out on the CTAF, 123.05, to the other aircraft, not to a controller. The runway shown is 10; use whichever runway the wind and the traffic dictate on the day.

The aircraft is the AIM’s own example, Cessna Three One Six Zero Foxtrot; the squawk codes, altitudes and headings are illustrative. Frequencies, station names and runway numbers are this airport’s, from the FAA data.

  1. Tune 123.05. Nobody clears you; you announce and you listen. The airport name goes at the start and the end of every call, and the runway is always a number, never "the active" (AIM 4-1-9 g 8).
  2. YouKnox County traffic, Cessna Three One Six Zero Foxtrot, taxiing to runway one zero, Knox County.
  3. YouKnox County traffic, Cessna Six Zero Foxtrot, departing runway one zero, departing the pattern to the north, Knox County.
  4. Announce until you are about 10 miles out; on the way back, start announcing at 10 miles (AIM 4-1-9 c 1, TBL 4-1-1).
  5. YouKnox County traffic, Cessna Three One Six Zero Foxtrot, one zero miles south, two thousand five hundred, landing Knox County, Knox County.
  6. YouKnox County UNICOM, Cessna Six Zero Foxtrot, one zero miles south, request wind and runway information, Knox County.
  7. A UNICOM operator, if one is on, answers with the wind and the runway in use (AIM 4-1-9 h). If nobody answers, choose the runway from the wind and the pattern traffic you can hear.
  8. YouKnox County traffic, Cessna Six Zero Foxtrot, entering left downwind runway one zero, full stop, Knox County.
  9. YouKnox County traffic, Cessna Six Zero Foxtrot, left base runway one zero, Knox County.
  10. YouKnox County traffic, Cessna Six Zero Foxtrot, final runway one zero, full stop, Knox County.
  11. YouKnox County traffic, Cessna Six Zero Foxtrot, clear of runway one zero, Knox County.

If things change. Want flight following after departure? Call Columbus Approach on 125.95 once clear of the pattern: identification, type, position, altitude, destination, "request VFR flight following" (AIM 4-1-18 a 3). Do not use "any traffic in the area, please advise"; the AIM says it is not to be used under any condition (AIM 4-1-9 g 1).

Phraseology from AIM 4-1-9 c 1, g 1, g 8, h; TBL 4-1-1; 4-3-3. What TowerTalk grades against →

The calls you will make here

Nearby in Ohio

Frequencies, runways and airspace from the FAA National Airspace System Resources (NASR) 28-day subscription, cycle effective Oct 29, 2026. Training use only. Always verify against a current Chart Supplement and sectional chart before flight; frequencies change. TowerTalk is not affiliated with the FAA. Report a discrepancy.