Private Pilot Flight Training and Instruction Flight Training Article Library | Back To 4VFR.COM Light Series The light gun is used by ATC towers, in the event of radio failure, to move and sequence aircraft. In general all GREEN signals permit progress except a flashing green in the air means return. All RED signals mean don't or stop except on the ground the flashing red means clear the runway. A flashing white has no meaning in the air and means to return on the ground. With prior arrangement, light signals may be used to leave or enter a controlled airport. One way to learn the light signals is by their peculiarities: Steady red means to stop on the ground and to stop in the air which can only be done by circling. The other red light means to move (leave) in the air and on the ground. The flashing red on the ground tells you to move clear from the runway or whereever you are. The area is unsafe. In the air the same flashing red means the airport is unsafe for landing which is another way of telling you to move out of the area. The alternating red and green suggests extreme caution air or ground. It is the only light other than the steady green, that means the same both in the air and on the ground. Steady green means to takeoff or land. The flashing green clears you for taxi, and in the air, to return to await landing clearance of steady green. The flashing white only applies to ground movement and tells you to return from whence you started. A steady white has no meaning any time. A good procedure for practice is to face the tower during run-up and ask ground control for a light series. The sires may be continuous or you can ask for specific series such as "return to parking", "move from present position", etc. It is better to practice this way than just to see lights. Written by Gene Whitt Flight Training Article Library | Back To 4VFR.COM