PA.II.D.K6bFAA-S-ACS-6C · Nov 2023Knowledge

b. Radio communications at towered and nontowered airports

ACS element text (the applicant demonstrates understanding of)

Procedures for: b. Radio communications at towered and nontowered airports

Bottom line

Pilots operating from a towered airport are required to maintain two-way radio communication with ATC and to acknowledge and comply with their instructions. The key to communicating at an airport without an operating control tower is selection of the correct common frequency.

Key numbers

Key numbers for b. Radio communications at towered and nontowered airports
NumberWhat it means
122.9MULTICOM
122.7, 122.8, 122.725, 122.975, or 123.0UNICOM CTAF
10 miles to landingInbound
start-up to 10 milesDeparting
8 to 10 miles outStraight-in

FAA references

  1. PHAK ch. 14 (p. 14-2) — FAA-H-8083-25C (2023)
  2. AIM 4-1-9 (Traffic Advisory Practices at Airports Without Operating Control Towers) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
  3. AIM 4-1-5 (Communications Release of IFR Aircraft Landing at an Airport Without an Operating Control Tower) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
  4. AIM 4-2-13 (Communications with Tower when Aircraft Transmitter or Receiver or Both are Inoperative) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
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