CA.III.A.K1FAA-S-ACS-7B · Nov 2023Knowledge
How to obtain appropriate radio frequencies.
How to obtain appropriate radio frequencies.
Bottom line
A CTAF is a frequency designated for the purpose of carrying out airport advisory practices while operating to or from an airport without an operating control tower. The CTAF may be a Universal Integrated Community (UNICOM), MULTICOM, Flight Service Station (FSS), or tower frequency and is identified in appropriate aeronautical publications.
Key numbers
| Number | What it means |
|---|---|
| more than 30 minutes flying time or 100 NM from nearest shore | Overwater radio |
| no more than a 30-minute gap | VHF gap |
FAA references
- PHAK ch. 14 (p. 14-2) — FAA-H-8083-25C (2023)
- 14 CFR 91.511 (Communication and navigation equipment for overwater operations.) — eCFR current as of 2026-03-05
- AFH Glossary (p. G-4) — FAA-H-8083-3C
- 14 CFR 91.131 (Operations in Class B airspace.) — eCFR current as of 2026-03-05
- RMH ch. 8 (p. 8-4) — FAA-H-8083-2A
- AFH ch. 13 (p. 13-15) — FAA-H-8083-3C
- PHAK ch. 14 (p. 14-23) — FAA-H-8083-25C (2023)
- AIM 6-3-2 (Obtaining Emergency Assistance) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
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