Section 2. Visual Signals

1. LIGHT SIGNALS

Use ATC light signals from TBL 3-2-1 to control aircraft and the movement of vehicles, equipment, and personnel on the movement area when radio communications cannot be employed.

1. WARNING SIGNAL

Direct a general warning signal, alternating red and green, to aircraft or vehicle operators, as appropriate, when:

1. Aircraft are converging and a collision hazard exists.
2. Mechanical trouble exists of which the pilot might not be aware.
3. Other hazardous conditions are present which call for intensified pilot or operator alertness. These conditions may include obstructions, soft field, ice on the runway, etc.

1. RECEIVER‐ONLY ACKNOWLEDGMENT

To obtain acknowledgment from an aircraft equipped with receiver only, request the aircraft to do the following:

1. Fixed‐wing aircraft:

1. Between sunrise and sunset:

1. Move ailerons or rudders while on the ground.
2. Rock wings while in flight.

1. Between sunset and sunrise: Flash navigation or landing lights.

1. Helicopters:

1. Between sunrise and sunset:

1. While hovering, either turn the helicopter toward the controlling facility and flash the landing light or rock the tip path plane.
2. While in flight, either flash the landing light or rock the tip path plane.

1. Between sunset and sunrise: Flash landing light or search light.