AIRCRAFT LIGHTING

Aircraft Lighting

Landing lights are lights used on aircraft to illuminate the terrain and runway ahead during takeoff and landing.

Almost all modern aircraft are equipped with landing lights if they are intended and approved for nighttime operations. Landing lights are usually of very high intensity because of the considerable distance that may separate an aircraft from terrain or obstacles; the landing lights of large aircraft can easily be seen by other aircraft over 100 miles away.

In the design of landing lights, key considerations are intensity, reliability, weight, and power consumption. Ideal landing lights are extremely intense, require little electrical power, are lightweight, and have long and predictable service lives. Technologies used in past and present have included ordinary incandescent lamps, halogen lamps, various forms arc lamps and discharge lamps, and LED lamps.

Landing lights on a Royal Jordanian Airbus A310, two on the nose undercarriage leg and two on the wings. Click on the picture to see them more clearly.

Landing lights are typically only useful as visibility aids to the pilots when the aircraft is very low and close to terrain, as during take-off and landing. Landing lights are usually extinguished in cruise flight, especially if atmospheric conditions are likely to cause reflection or glare from the lights back into the eyes of the pilots. However, the brightness of the landing lights makes them useful for increasing the visibility of an aircraft to other pilots, and so pilots are often encouraged to keep their landing lights on while in flight below certain altitudes or in crowded airspaces. Some aircraft (especially business jets) have lights that can be operated in a flashing mode when not needed to directly illuminate the ground to enhance the visbility of the aircraft further. One convention is for commercial aircraft to turn on their landing lights when changing flight levels.

Landing lights are sometimes used in emergencies to communicate with ground personnel or other aircraft, especially if other means of communication are not available (radio failures and the like).

Landing lights on a Royal Jordanian Airbus A310, two on the nose undercarriage leg and two on the wings. Click on the picture to see them more clearly.

Landing lights are typically only useful as visibility aids to the pilots when the aircraft is very low and close to terrain, as during take-off and landing. Landing lights are usually extinguished in cruise flight, especially if atmospheric conditions are likely to cause reflection or glare from the lights back into the eyes of the pilots. However, the brightness of the landing lights makes them useful for increasing the visibility of an aircraft to other pilots, and so pilots are often encouraged to keep their landing lights on while in flight below certain altitudes or in crowded airspaces. Some aircraft (especially business jets) have lights that can be operated in a flashing mode when not needed to directly illuminate the ground to enhance the visbility of the aircraft further. One convention is for commercial aircraft to turn on their landing lights when changing flight levels.

Landing lights are sometimes used in emergencies to communicate with ground personnel or other aircraft, especially if other means of communication are not available (radio failures and the like).

 

Wingtip devices increase the lift generated at the wingtip (by smoothing the airflow across the upper wing near the tip) and reduce the lift-induced drag caused by wingtip vortices, improving lift-to-drag ratio. This increases fuel efficiency in powered aircraft and increases cross-country speed in gliders, in both cases increasing range.

Lights of special significance

In addition to red, white and green running lights, a combination of red, white and green Mast Lights placed on a mast higher than all the running lights, and viewable from all directions, may be used to indicate the type of craft or the service it is performing.

Wingtip devices are usually intended to improve the efficiency of fixed-wing aircraft.^[1] There are several types of wingtip devices, and though they function in different manners, the intended effect is always to reduce the aircraft's drag by altering the airflow near the wingtips. Wingtip devices can also improve aircraft handling characteristics and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing without materially increasing the wingspan. An extension of span would lower lift-induced drag, but would increase parasitic dragand would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan (e.g., available width at airport gates).