13.runway-markings-and-lighting. Runway Markings and Lighting
Runway markings and lighting provide pilots with critical visual information for safe taxi, takeoff, approach, and landing operations. Standardized by the FAA and ICAO, these visual aids communicate runway type, dimensions, usable surface, and operational status both day and night.
Runway Markings
Runway markings are white and vary by the type of approach the runway supports. The three categories are:
- Visual runways — used for VFR operations and not equipped with an instrument approach. Markings include the runway designation number and centerline. Threshold markings and aiming point markings are optional.
- Nonprecision instrument runways — serve straight-in nonprecision approaches (e.g., VOR, LOC, RNAV LNAV). Markings include the designation, centerline, threshold, and aiming point.
- Precision instrument runways — serve ILS or PAR approaches. Add touchdown zone markings and side stripes to the nonprecision set.
Key marking elements include:
- Runway designators — one or two digits representing the magnetic azimuth of the runway centerline rounded to the nearest 10 degrees, with the trailing zero dropped (Runway 9 = 090°). Parallel runways add L, C, or R.
- Centerline — a dashed white line down the middle of the runway.
- Threshold markings — eight longitudinal stripes (the "piano keys") identify the beginning of the runway available for landing. The number of stripes can also indicate runway width (e.g., 8 stripes = 100 ft).
- Aiming point — two broad white stripes located 1,000 ft from the threshold, providing a visual aiming reference.
- Touchdown zone (TDZ) markings — coded groups of one, two, and three rectangular bars on each side of the centerline at 500-ft increments, extending 3,000 ft from the threshold (or to midpoint, whichever is less).
- Side stripes — solid white lines defining the lateral edges of the runway.
- Displaced threshold — a threshold not located at the beginning of the paved surface. The pavement before the threshold (marked with white arrows) is available for taxi, takeoff, and landing rollout, but not for landing.
- Blast pad/stopway — yellow chevrons indicate pavement that is unusable for taxi, takeoff, and landing.
- Closed runway — marked with a yellow X.
Runway Holding Position Markings
Four yellow lines (two solid, two dashed) at the entrance to the runway from a taxiway. Aircraft must stop on the side of the solid lines unless cleared to cross or enter. The solid lines always face the side that must hold short.
Runway Lighting
Runway lighting allows operations at night and in low visibility. Most systems are pilot- or controller-controlled.
- Runway Edge Lights — white lights along both edges of the runway, classified by intensity as HIRL (high), MIRL (medium), or LIRL (low). The last 2,000 ft (or half the runway length, whichever is less) appear yellow when viewed from the landing direction, providing a caution zone.
- Runway End Identifier Lights (REIL) — a pair of synchronized flashing white lights at the threshold to provide rapid and positive identification of the approach end.
- Runway Centerline Lighting System (RCLS) — flush white lights along the centerline at 50-ft intervals on Category II/III runways. Lights alternate red/white between 3,000 ft and 1,000 ft from the rollout end, then turn solid red for the final 1,000 ft.
- Touchdown Zone Lights (TDZL) — two rows of transverse white light bars on either side of the centerline, extending 3,000 ft from the threshold or to midpoint.
- Threshold Lights — green when viewed on approach, red when viewed from the runway (indicating runway end).
- Taxiway Lights — blue edge lights and green centerline lights distinguish taxiways from runways.
Approach Light Systems (ALS)
ALS provide the basic means of transitioning from instrument to visual flight. Common configurations include ALSF-2 (precision Category II/III), MALSR (medium-intensity with RAIL for ILS), and ODALS (omnidirectional flashing for nonprecision).
Visual Glideslope Indicators
- VASI — typically a two-bar system. White over white = too high; red over white = on glide path; red over red = too low ("red over red, you're dead").
- PAPI — four lights in a single row, normally on the left side. Four white = high; three white/one red = slightly high; two white/two red = on glide path (typically 3°); one white/three red = slightly low; four red = low.
- Tri-color VASI — amber (high), green (on path), red (low).
Pilot-Controlled Lighting (PCL)
At many uncontrolled fields, lights are activated by keying the CTAF microphone: 7 clicks within 5 seconds = high intensity, 5 clicks = medium, 3 clicks = low. Each activation resets a 15-minute timer.
Understanding these markings and lighting elements is essential for runway identification, runway incursion avoidance, stabilized approaches, and safe night operations.