AIM Text
- Runway Centerline Lighting System (RCLS). Runway centerline lights are installed on some precision approach runways to facilitate landing under adverse visibility conditions. They are located along the runway centerline and are spaced at 50-foot intervals. When viewed from the landing threshold, the runway centerline lights are white until the last 3,000 feet of the runway. The white lights begin to alternate with red for the next 2,000 feet, and for the last 1,000 feet of the runway, all centerline lights are red.
- Touchdown Zone Lights (TDZL). Touchdown zone lights are installed on some precision approach runways to indicate the touchdown zone when landing under adverse visibility conditions. They consist of two rows of transverse light bars disposed symmetrically about the runway centerline. The system consists of steady-burning white lights which start 100 feet beyond the landing threshold and extend to 3,000 feet beyond the landing threshold or to the midpoint of the runway, whichever is less.
- Taxiway Centerline Lead-Off Lights. Taxiway centerline lead-off lights provide visual guidance to persons exiting the runway. They are color-coded to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system (ILS) critical area, whichever is more restrictive. Alternate green and yellow lights are installed, beginning with green, from the runway centerline to one centerline light position beyond the runway holding position or ILS critical area holding position.
- Taxiway Centerline Lead-On Lights. Taxiway centerline lead-on lights provide visual guidance to persons entering the runway. These “lead-on” lights are also color-coded with the same color pattern as lead-off lights to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system (ILS) critical area, whichever is more conservative. The fixtures used for lead-on lights are bidirectional, i.e., one side emits light for the lead-on function while the other side emits light for the lead-off function. Any fixture that emits yellow light for the lead-off function must also emit yellow light for the lead-on function. (See FIG 2-1-12.)
- Land and Hold Short Lights. Land and hold short lights are used to indicate the hold short point on certain runways which are approved for Land and Hold Short Operations (LAHSO). Land and hold short lights consist of a row of pulsing white lights installed across the runway at the hold short point. Where installed, the lights will be on anytime LAHSO is in effect. These lights will be off when LAHSO is not in effect.
Source: FAA Aeronautical Information Manual · current edition · paragraph 2-1-5.
The short answer
This AIM section is FAA advisory guidance on in-runway lighting, covering the Runway Centerline Lighting System (RCLS), Touchdown Zone Lights (TDZL), taxiway centerline lead-off and lead-on lights, and Land and Hold Short lights. These in-pavement systems help pilots land under adverse visibility and identify the runway environment and ILS critical areas during ground operations.
Research Notes
Common Questions
What do the runway centerline lights mean as I roll out?
Runway centerline lights (RCLS) are spaced at 50-foot intervals. Viewed from the landing threshold, they are white until the last 3,000 feet of the runway; the white lights then alternate with red for the next 2,000 feet, and for the last 1,000 feet all centerline lights are red — warning the pilot of the approaching runway end.
Where are touchdown zone lights installed?
Touchdown zone lights (TDZL) are installed on some precision approach runways and consist of two rows of transverse light bars symmetrical about the runway centerline. The steady-burning white lights start 100 feet beyond the landing threshold and extend to 3,000 feet beyond the threshold or to the midpoint of the runway, whichever is less.
What do the green and yellow taxiway centerline lights indicate?
Alternate green and yellow taxiway centerline lead-off and lead-on lights warn pilots and vehicle drivers that they are within the runway environment or ILS critical area, whichever is more restrictive. They begin with green from the runway centerline to one centerline light position beyond the runway holding position or ILS critical area holding position. Land and Hold Short lights, by contrast, are a row of pulsing white lights at the hold short point, on whenever LAHSO is in effect.