Evaluation of Lighted Crossbars and Lighted Runway Distance Markers

Lighted crossbars extending across the width of the runway spaced at 1000-foot intervals, and internally lighted frangible distance markers adjacent to the runway also spaced at 1000 -foot intervals, were evaluated at the National Aviation Facilities Experimental Center (NAFEC), Atlantic City, New Jersey, to determine a suitable system for providing runway distance-to-go information during takeoff and landing operations. Painted numerals, of the type developed and used in the United Kingdom, were also appraised. Flight testing was conducted in unlimited and restricted visibility conditions. Portions of the restricted visibility conditions were simulated using the Cockpit Fog Simulator of the Link Division, General Precision, .Inc., and fixed density sheets of Mylar film to obtain a runway visual range (RVR) of approximately 1500 feet.

It was determined that crossbars alone did not provide adequate distance -to-go information. Distance markers were not as effective as painted numerals under the lower visibility conditions. Crossbars when added to distance markers did not substantially improve the information obtained. High wind and engine blast effects caused marker damage.

Numerals painted on the runway surface and located near the runway centerline were more effective than lighted runway-distance markers under the lower visibility conditions.

It was recommended that the suitability of a combination of lighted runway-distance markers and numerals painted on the runway surface for providing distance-to-go information for civil aircraft operations be confirmed by an in-service test.

Author: F.J. Meehan