9.6 Radio Communications, Traffic Patterns & ATC Services
Key Takeaways
- Propeller-driven airplanes enter the traffic pattern at 1,000 feet AGL unless another altitude is published, and all pattern turns are to the left unless otherwise indicated (AIM 4-3-3).
- When departing a non-towered airport's pattern, continue straight out or make a 45° turn in the pattern direction beyond the runway's departure end after reaching pattern altitude.
- A steady green light gun signal clears an aircraft for takeoff on the ground or to land in flight; flashing green clears it to taxi or to return for landing.
- When making routine transponder code changes, pilots should avoid inadvertently selecting 7500, 7600, or 7700, the hijack, radio failure, and emergency codes.
- The AIM encourages landing lights on below 10,000 feet, day or night, especially within 10 miles of an airport, in reduced visibility, and where birds may be expected.
Radio Communications, Traffic Patterns & ATC Services
The private pilot knowledge areas include radio communication procedures (14 CFR 61.105(b)(5)), and the commercial areas include procedures for operating within the National Airspace System (61.125(b)(15)). The FAA's published AGI sample questions ask about departing a non-towered airport, light gun signals, transponder codes to avoid, and when to use landing lights. The primary sources are AIM Chapter 4 and AC 90-66C, Non-Towered Airport Flight Operations.
Radio Technique
A good initial call follows the AIM's order: who you are calling, who you are, where you are, and what you want, followed by the ATIS code if one is available. For example: "Centerville Tower, Cessna Two Three Four Five Kilo, ten miles south, landing with information Bravo."
- Use the ICAO phonetic alphabet and pronounce 9 as "niner."
- State altitudes in thousands and hundreds ("one two thousand five hundred") and headings as three digits ("heading zero niner zero").
- Read back runway assignments, clearances to enter or cross runways, and hold short instructions; ATC expects them.
- At a non-towered airport, self-announce on the Common Traffic Advisory Frequency (CTAF), which may be a UNICOM, a MULTICOM (122.9), or a Flight Service frequency. Begin and end each report with the airport name, because several airports may share the frequency. AC 90-66C recommends calls about 10 miles out, entering downwind, on base, on final, and when clear of the runway.
- 121.5 MHz is the emergency frequency. Flight Service is reached on published frequencies and by phone at 1-800-WX-BRIEF.
The Standard Traffic Pattern
| Item | AIM 4-3-3 and AC 90-66C Guidance |
|---|---|
| Pattern altitude | Propeller-driven airplanes: 1,000 feet AGL; large and turbine-powered airplanes: at least 1,500 feet AGL or 500 feet above the established pattern altitude; unless the Chart Supplement publishes a different altitude |
| Direction | Left turns unless otherwise indicated; right patterns are shown on charts as "RP" plus the runway number and by traffic pattern indicators at the segmented circle |
| Entry | Enter in level flight at pattern altitude, typically on a 45° angle to the downwind leg, abeam the midpoint of the runway |
| Downwind to final | Maintain pattern altitude until abeam the approach end; complete the turn to final at least ¼ mile from the runway |
| Remaining in the pattern | Continue straight ahead until beyond the departure end; turn crosswind within 300 feet of pattern altitude |
| Departing the pattern | Continue straight out, or exit with a 45° turn in the direction of the pattern (left for a left pattern) beyond the departure end of the runway, after reaching pattern altitude |
At airports with an operating control tower, the controller's instructions govern, but the pattern shape is the same. Under 14 CFR 91.126 and 91.127, airplanes approaching to land at an airport without a tower in Class G or Class E airspace must make all turns to the left unless markings or lights indicate otherwise.
ATC Light Gun Signals
When a radio fails at a towered airport, the tower uses light gun signals (AIM 4-3-13):
| Signal | Aircraft on the Ground | Aircraft in Flight |
|---|---|---|
| Steady green | Cleared for takeoff | Cleared to land |
| Flashing green | Cleared to taxi | Return for landing (to be followed by steady green) |
| Steady red | Stop | Give way to other aircraft and continue circling |
| Flashing red | Taxi clear of the runway in use | Airport unsafe, do not land |
| Flashing white | Return to starting point on airport | Not applicable |
| Alternating red and green | Exercise extreme caution | Exercise extreme caution |
VFR radio failure: squawk 7600, remain in VMC, and land as soon as practicable. Approaching a towered airport, stay outside or above the Class D airspace until you determine the direction and flow of traffic, join the pattern, and watch the tower for light signals. Acknowledge signals in flight by rocking the wings during daylight or flashing the landing or navigation lights at night.
Transponder Codes and Conspicuity
| Code | Meaning |
|---|---|
| 1200 | VFR, not in contact with ATC |
| 7500 | Hijack |
| 7600 | Two-way radio communication failure |
| 7700 | Emergency |
When making routine code changes, pilots should avoid inadvertent selection of 7500, 7600, or 7700, which can trigger momentary false alarms at automated ATC facilities (AIM 4-1-20). Mode C and ADS-B Out requirements are covered in Section 9.4.
The AIM's "operation lights on" program encourages pilots to turn on landing lights when operating below 10,000 feet, day or night, especially within 10 miles of any airport, in conditions of reduced visibility, and where flocks of birds may be expected. Landing lights should also be turned on when takeoff clearance is received, or when starting the takeoff roll at an airport without a tower.
ATC Services for VFR Pilots
- Radar traffic advisories (flight following): available on a workload-permitting basis from approach control or an ARTCC. They do not relieve the pilot of see-and-avoid responsibility.
- Class C and Class B services: separation or sequencing services within those areas, as described in the AIM.
- Flight Service: preflight briefings, flight plans, and inflight advisories.
- Collision avoidance: AC 90-48D notes that most midair collisions and near midair collisions happen in good weather and in daylight, with many near airports. The AIM scanning technique (short eye movements of no more than 10°, pausing about 1 second in each sector) and radio calls on the correct frequency are the pilot's best defenses; see Sections 2.3 and 12.4.
According to the AIM, what is the correct procedure for departing the traffic pattern at a non-towered airport that uses a left-hand pattern?
While on final approach at a towered airport with a failed radio, a pilot receives a flashing green light from the tower. What does it mean?
When making routine transponder code changes, pilots should avoid inadvertently selecting which codes?
The AIM encourages pilots to turn on their landing lights when operating below 10,000 feet, day or night, especially