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AIM 

4/20/23

 

4

3

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Airport Operations

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

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

3

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

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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

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

REFERENCE

AIM, Para 4

1

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

up block unless advised otherwise.

c.

The majority of ground control frequencies are in the 121.6

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