Runway end identifier lights (REIL) (ICAO identifies these as Runway Threshold Identification Lights) are installed at many

airport An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surfa ...

s to provide rapid and positive identification of the approach end of a particular

runway According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt concrete, as ...

. The system consists of a pair of synchronized flashing lights located laterally on each side of the runway threshold. REILs may be either omnidirectional or unidirectional facing the approach area.FAA Aeronautical Information Manual, Chapter 2 (Aeronautical Lighting and Other Airport Visual Aids), Section 1 (Airport Lighting Aids)
They are effective for: * Identification of a runway surrounded by a preponderance of other lighting * Identification of a runway which lacks contrast with surrounding terrain * Identification of a runway during reduced visibility The

International Civil Aviation Organization The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international ...

(ICAO) recommends that: §5.3.8, "Runway threshold identification lights" * Runway threshold identification lights should be installed: ** at the threshold of a non-precision approach runway when additional threshold conspicuity is necessary or where it is not practicable to provide other approach lighting aids; and ** where a runway threshold is permanently displaced from the runway extremity or temporarily displaced from the normal position and additional threshold conspicuity is necessary. * Runway threshold identification lights shall be located symmetrically about the runway centre line, in line with the threshold and approximately 10 meters outside each line of runway edge lights. * Runway threshold identification lights should be flashing white lights with a flash frequency between 60 and 120 per minute. * The lights shall be visible only in the direction of approach to the runway.

References

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External links

FAA Aeronautical Information Manual
Airport lighting