Plain English Meaning

Two sets of lights built into the runway surface that help pilots see exactly where to touch down and where the centerline runs during a low-visibility landing. If either set is out of service, the published landing minimums on the approach plate may need to be raised before the approach can legally be flown.

Full Definition

A combined reference to two in-pavement runway lighting systems used on precision instrument runways. Touchdown Zone Lighting (TDZ) consists of two rows of transverse white light bars installed symmetrically about the runway centerline in the touchdown zone, beginning 100 feet beyond the landing threshold and extending 3,000 feet down the , or to the , whichever is less. (CL) consists of flush white lights spaced 50 feet apart along the runway centerline, transitioning to alternating white and red, then to all red, as the runway end . When TDZ/CL is listed as , certain on the approach must be raised in accordance with the .