USA TODAY International Edition
Airplane, airport lights perform vital functions
Question: Why does the air traffic control tower have a green and white light on top that rotates?
– Duncan, Lake Tahoe, Nevada Answer: It indicates that it is a civilian airfield. Pilots see alternating green and white flashes. Military airfields have two white flashes followed by a green one.
Q: At what point in the approach are the landing lights turned on? What is their real purpose?
– JD, Hilton Head, South Carolina A: It varies by the operator and the individual pilot. Some operators illuminate the landing lights below 18,000 feet, others at 10,000 feet. During the night, they provide illumination to help the pilot judge the distance above the runway during landing. They also improve the visibility of the aircraft to other airplanes and birds.
Q: Other than the red and green lights at the end of the wings, are the exterior lights configured specifically for an aircraft?
– Glenn K. Rutz, Villa Park, Illinois
A: Yes, there is a white light in the tail, there are red blinking lights on the top and bottom of the airplane, and often bright white blinking strobe lights on the wing tips.
Q: Regarding your column about the minimum equipment list, does that include lighting?
– Ted W., New Jersey
A: Some planes have two navigation lights in each required position (wing tip and tail). This allows them to continue flying if one fails. Otherwise, navigation lights are required at night.
John Cox is a retired airline captain with US Airways.