AIM Text
- Arriving Aircraft.
- Receiver inoperative.
- If you have reason to believe your receiver is inoperative, remain outside or above the Class D surface area until the direction and flow of traffic has been determined; then, advise the tower of your type aircraft, position, altitude, intention to land, and request that you be controlled with light signals.
- When you are approximately 3 to 5 miles from the airport, advise the tower of your position and join the airport traffic pattern. From this point on, watch the tower for light signals. Thereafter, if a complete pattern is made, transmit your position downwind and/or turning base leg.
- Transmitter inoperative. Remain outside or above the Class D surface area until the direction and flow of traffic has been determined; then, join the airport traffic pattern. Monitor the primary local control frequency as depicted on Sectional Charts for landing or traffic information, and look for a light signal which may be addressed to your aircraft. During hours of daylight, acknowledge tower transmissions or light signals by rocking your wings. At night, acknowledge by blinking the landing or navigation lights. To acknowledge tower transmissions during daylight hours, hovering helicopters will turn in the direction of the controlling facility and flash the landing light. While in flight, helicopters should show their acknowledgement of receiving a transmission by making shallow banks in opposite directions. At night, helicopters will acknowledge receipt of transmissions by flashing either the landing or the search light.
- Transmitter and receiver inoperative. Remain outside or above the Class D surface area until the direction and flow of traffic has been determined; then, join the airport traffic pattern and maintain visual contact with the tower to receive light signals. Acknowledge light signals as noted above.
- Receiver inoperative.
- Departing Aircraft. If you experience radio failure prior to leaving the parking area, make every effort to have the equipment repaired. If you are unable to have the malfunction repaired, call the tower by telephone and request authorization to depart without two‐way radio communications. If tower authorization is granted, you will be given departure information and requested to monitor the tower frequency or watch for light signals as appropriate. During daylight hours, acknowledge tower transmissions or light signals by moving the ailerons or rudder. At night, acknowledge by blinking the landing or navigation lights. If radio malfunction occurs after departing the parking area, watch the tower for light signals or monitor tower frequency.
Source: FAA Aeronautical Information Manual · current edition · paragraph 4-2-13.
Research Notes
AIM 4-2-13 covers directions in ATC communications — how compass headings and turn directions are expressed.
Headings: Three digits, magnetic course. "Heading zero-niner-zero" (090° magnetic), "Heading two-seven-zero" (270° magnetic). Always three digits — "heading nine zero" is unacceptable.
Turns: The controller specifies LEFT or RIGHT and the heading:
- "Turn right, heading one-eight-zero"
- "Turn left, heading three-six-zero" (which is the same as "north")
Compass references: "Direct" + a fix is a course-to-fix command. "Proceed direct" or "direct to" + fix means fly the great-circle course from present position.
Climbs and descents in turns: Controllers may combine: "Climb and maintain seven thousand, turn right heading one-eight-zero." Read back both items.
Reference: AIM 4-2-13.