ATC Light Signals

FAR 91.125 — ATC Light Signals

FAR 91.125 defines ATC light gun signals for aircraft in flight and on the ground. Learn each color and meaning for your checkride and written test.

In Plain English

FAR 91.125 lists the ATC light gun signals that controllers use when an aircraft has lost radio communication or is operating NORDO. You must memorize each signal because it's the only way the tower can communicate with you when the radios are out. Each signal has a different meaning depending on whether you are in flight or on the surface.

Steady green — On the surface: cleared for takeoff. In flight: cleared to land.
Flashing green — On the surface: cleared to taxi. In flight: return for landing (to be followed by a steady green at the proper time).
Steady red — On the surface: stop. In flight: give way to other aircraft and continue circling.
Flashing red — On the surface: taxi clear of the runway in use. In flight: airport unsafe—do not land.
Flashing white — On the surface: return to starting point on airport. Not applicable in flight.
Alternating red and green — Exercise extreme caution (both in flight and on the surface).

Knowing these cold lets you safely complete a pattern, taxi, takeoff, or landing if you experience a radio failure at a towered field.

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Regulation Text

14 CFR § 91.125

§ 91.125 ATC light signals. ATC light signals have the meaning shown in the following table: Exercise extreme caution. Exercise extreme caution Alternating red and green Not applicable. Return to starting point on airport Flashing white Airport unsafe—do not land. Taxi clear of runway in use Flashing red Give way to other aircraft and continue circling. Stop Steady red Return for landing (to be followed by steady green at proper time). Cleared to taxi Flashing green Cleared to land. Cleared for takeoff Steady green Meaning with respect to aircraft in flight Meaning with respect to aircraft on the surface Color and type of signal

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You are flying VFR in Class E airspace at 8,500 feet MSL during the day. What are your minimum visibility and cloud clearance requirements?

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Oral Exam Questions a DPE Might Ask

Q1You're on downwind at a towered airport and lose your radios. The tower flashes a steady green light at you. What does that mean and what do you do?

Per FAR 91.125, a steady green light to an aircraft in flight means cleared to land. I would continue the approach and land normally while watching for further signals.

Q2What does an alternating red and green light signal mean?

Under FAR 91.125, alternating red and green means exercise extreme caution, and it applies to aircraft both in flight and on the surface.

Q3While taxiing for departure with a radio failure, you receive a flashing red light from the tower. What is the controller telling you?

FAR 91.125 states that a flashing red light to an aircraft on the surface means taxi clear of the runway in use. I would exit the runway promptly and hold for further signals.

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