Runway Status Lights: Takeoff Hold Lighting System Evaluation

Takeoff hold lights (THL) are positioned along the runway centerline, and when illuminated, they are visible to an aircraft pilot at the beginning of the runway preparing for takeoff. Normally, these lights are off. A Runway Status Light (RWSL) System monitors the runway occupancy status and conveys this information to the pilots, ground vehicle operators, and others using special lighting components such as the THLs. Specifically, when a runway is occupied, the RWSL System turns on the THLs and provides a conspicuous visual warning to pilots preparing for takeoff that they should not continue.

 Project personnel from the Federal Aviation Administration (FAA) Airport Safety Technology Research and Development Subteam evaluated four THL configurations on Runway 13 at the Atlantic City International Airport. Three configurations contained a double row of red lights and one contained a single row of red lights. Project personnel collected data on the appearance of each configuration and recorded their findings on questionnaires.

 The results of this evaluation validated previous findings by the FAA Airport Safety Technology Research and Development Subteam that the double-row THL configuration spaced 6 ft from the runway centerline was more effective than the other three configurations. The 6-ft spacing created very distinct lines that did not, at any time, blend with the runway centerline fixtures. As a result, this configuration created a more conspicuous signal that was easily acquired by the pilots. Using double-row THLs significantly enhanced the THL system.

DOT/FAA/AR-TN09/25
Author: James Patterson