Non-Towered Airport Flight Operations (AC 90-66C)
Advisory Circular 90-66C provides guidance for operations at non-towered airports including traffic pattern procedures, radio communication practices, and right-of-way rules. It covers standard traffic pattern entry and departure, recommended communication phraseology on CTAF frequencies, and procedures for handling conflicts at airports without air traffic control.
Why This Document Matters
Most airports in the United States are non-towered, and this AC is the definitive guide to operating at them safely. It covers standard traffic pattern entry (45-degree to downwind), straight-in approaches, communication on CTAF/UNICOM frequencies, and how to handle conflicting traffic. The 2023 revision (C) updated guidance on traffic pattern operations and clarified several long-debated topics. Every pilot should be familiar with this AC, especially for the practical test where DPEs expect proper non-towered procedures.
Chapter-by-Chapter Guide
What each section covers and the key topics to study
1Traffic Pattern Operations
Standard traffic pattern entry and departure procedures, pattern altitude, and right-of-way.
Traffic Pattern Operations
Standard traffic pattern entry and departure procedures, pattern altitude, and right-of-way.
Key Topics
2Radio Communications at Non-Towered Airports
CTAF procedures, recommended phraseology, position reporting, and AWOS/ASOS usage.
Radio Communications at Non-Towered Airports
CTAF procedures, recommended phraseology, position reporting, and AWOS/ASOS usage.
Key Topics
Study Tips
- Know the standard traffic pattern entry: overfly midfield at pattern altitude + 500 feet, then descend into a 45-degree entry to the downwind leg.
- Practice self-announce radio calls — the format is always: airport name, your aircraft type and call sign, position, and intentions.
- Understand when a straight-in approach is acceptable and when the 45-degree entry is preferred — this is a common DPE discussion topic.
Frequently Asked Questions
Are radio calls required at non-towered airports?
Radio communications are not legally required at non-towered airports (unless in Class E surface area or other specific situations), but they are strongly recommended by the FAA. AC 90-66C provides the recommended procedures. Operating NORDO (no radio) is legal but requires extra vigilance and doesn't exempt you from right-of-way rules.
What is the standard traffic pattern altitude?
The standard traffic pattern altitude is 1,000 feet above ground level (AGL) for propeller-driven aircraft and 1,500 feet AGL for large or turbine-powered aircraft. Check the Chart Supplement (A/FD) for any airport-specific traffic pattern altitudes.
Quick Facts
- Document ID
- AC 90-66C
- Last Updated
- 2023
- Cost
- Free
- Publisher
- FAA
Applies To
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Non-Towered Airport Flight Operations (AC 90-66C) is an official FAA publication available at FAA.gov
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