AIM 

4/20/23 

equipment, and personnel equipped with radio if radio contact cannot be established. ATC personnel use a 

directive traffic control signal which emits an intense narrow light beam of a selected color (either red, white, 

or green) when controlling traffic by light signals. 

b. 

Although the traffic signal light offers the advantage that some control may be exercised over nonradio 

equipped aircraft, pilots should be cognizant of the disadvantages which are: 

1. 

Pilots may not be looking at the control tower at the time a signal is directed toward their aircraft. 

2. 

The directions transmitted by a light signal are very limited since only approval or disapproval of a pilot’s 

anticipated actions may be transmitted. No supplement or explanatory information may be transmitted except 

by the use of the “General Warning Signal” which advises the pilot to be on the alert. 

c. 

Between sunset and sunrise, a pilot wishing to attract the attention of the control tower should turn on a 

landing light and taxi the aircraft into a position, clear of the active runway, so that light is visible to the tower. 

The landing light should remain on until appropriate signals are received from the tower. 

d. 

Airport Traffic Control Tower Light Gun Signals. (See TBL 4

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3

−

1.) 

e. 

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. 

TBL 4

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3

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1 

Airport Traffic Control Tower Light Gun Signals 

Meaning 

Color and Type of Signal 

Movement of Vehicles, 

Equipment and Personnel 

Aircraft on the Ground 

Aircraft in Flight 

Steady green 

Cleared to cross, proceed or go 

Cleared for takeoff 

Cleared to land 

Flashing green 

Not applicable 

Cleared for taxi 

Return for landing (to be 

followed by steady green at the 

proper time) 

Steady red 

STOP 

STOP 

Give way to other aircraft and 

continue circling 

Flashing red 

Clear the taxiway/runway 

Taxi clear of the runway in use 

Airport unsafe, do not land 

Flashing white 

Return to starting point on airport  Return to starting point on airport  Not applicable 

Alternating red and green  Exercise extreme caution 

Exercise extreme caution 

Exercise extreme caution 

4

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3

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14.  Communications 

a. 

Pilots of departing aircraft should communicate with the control tower on the appropriate ground 

control/clearance delivery frequency prior to starting engines to receive engine start time, taxi and/or clearance 

information. Unless otherwise advised by the tower, remain on that frequency during taxiing and runup, then 

change to local control frequency when ready to request takeoff clearance. 

NOTE

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Pilots are encouraged to monitor the local tower frequency as soon as practical consistent with other ATC requirements. 

REFERENCE

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AIM, Para 4

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1

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13, Automatic Terminal Information Service (ATIS). 

b. 

The tower controller will consider that pilots of turbine

−

powered aircraft are ready for takeoff when they 

reach the runway or warm

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up block unless advised otherwise. 

c. 

The majority of ground control frequencies are in the 121.6

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121.9 MHz bandwidth. Ground control 

frequencies are provided to eliminate frequency congestion on the tower (local control) frequency and are limited 

to communications between the tower and aircraft on the ground and between the tower and utility vehicles on 

the airport, provide a clear VHF channel for arriving and departing aircraft. They are used for issuance of taxi 

4

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3

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20 

Airport Operations