Aircraft landing lights
Encyclopedia
Landing lights are lights used on aircraft
to illuminate the terrain and runway
ahead during takeoff
and landing
.
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 lamp
s, various forms arc lamp
s and discharge lamps, and LED
lamps.
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 level
s.
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).
The actual use of landing lights may or may not be required or forbidden by local regulations, depending on time of day or night, weather, airport conditions, aircraft conditions, the type of operation being carried out (take-off, landing, etc.), and other factors.
In the United States
, for example, landing lights are not required to be present or used for many types of aircraft, but their use is strongly encouraged, both for take-off and landing and during any operations below 10000 feet (3,048 m) AGL
or within ten nautical miles of an airport
. For transport category aircraft and some operations with other types of aircraft, landing lights are required to be present and used. Landing lights must be certified safe and adequate for their purpose before installation.
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
to illuminate the terrain and runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
ahead during takeoff
Takeoff
Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.For horizontal takeoff aircraft this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft , no...
and landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
.
Overview
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 lamp
Halogen lamp
A halogen lamp, also known as a tungsten halogen lamp, is an incandescent lamp with a tungsten filament contained within an inert gas and a small amount of a halogen such as iodine or bromine. The chemical halogen cycle redeposits evaporated tungsten back on to the filament, extending the life of...
s, various forms arc lamp
Arc lamp
"Arc lamp" or "arc light" is the general term for a class of lamps that produce light by an electric arc . The lamp consists of two electrodes, first made from carbon but typically made today of tungsten, which are separated by a gas...
s and discharge lamps, and LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....
lamps.
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
Business jet
Business jet, private jet or, colloquially, bizjet is a term describing a jet aircraft, usually of smaller size, designed for transporting groups of up to 19 business people or wealthy individuals...
) 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 level
Flight level
A Flight Level is a standard nominal altitude of an aircraft, in hundreds of feet. This altitude is calculated from the International standard pressure datum of 1013.25 hPa , the average sea-level pressure, and therefore is not necessarily the same as the aircraft's true altitude either...
s.
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).
Legal considerations
In many jurisdictions the landing light fixtures in the aircraft and the lamps they use must both be certified for use in a given aircraft by a government authority.The actual use of landing lights may or may not be required or forbidden by local regulations, depending on time of day or night, weather, airport conditions, aircraft conditions, the type of operation being carried out (take-off, landing, etc.), and other factors.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, for example, landing lights are not required to be present or used for many types of aircraft, but their use is strongly encouraged, both for take-off and landing and during any operations below 10000 feet (3,048 m) AGL
Above ground level
In aviation and atmospheric sciences, an altitude is said to be above ground level when it is measured with respect to the underlying ground surface. This is as opposed to above mean sea level , or in broadcast engineering, height above average terrain...
or within ten nautical miles of an airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
. For transport category aircraft and some operations with other types of aircraft, landing lights are required to be present and used. Landing lights must be certified safe and adequate for their purpose before installation.
See also
- Aircraft warning lightsAircraft warning lightsAircraft warning lights are high-intensity lighting devices that are attached to tall structures and are used as collision avoidance measures. Such devices make structures more visible to passing aircraft and are usually used at night, although they may be used during the day as well...
- Aviation navigation lights