Airport pavement markings provide critical information and guidance to pilots, ground vehicles, and airport staff—helping ensure they operate efficiently within safe boundaries and avoid accidents.
The State of Minnesota requires that markings at all state public airports meet FAA requirements, such as those found in Advisory Circular (AC) 150/5340-1M. This AC encompasses all of an airfield’s pavement, including runways, taxiways, and aprons. To ensure that an airport’s markings meet minimum standards, MnDOT refreshes or repaints markings on a reoccurring basis. At a minimum, all public airports in the state are repainted every four years.
Timing depends primarily on airport size, use, and weather. Typically, airports with more operations see markings deteriorate quickly compared to quieter airports. Weather and climate conditions, such as precipitation, freeze/thaw cycles, and humidity all affect how long markings last on an airport surface.
Markings for runways are white, while those for taxiways, areas not intended for use by aircraft (closed and hazardous areas), and holding positions are yellow. The paint used on markings must be kept to a minimal thickness for each application. If it exceeds this over time, all paint layers must be removed and reapplied. If this measurement, referred to as a “mil,” becomes too thick on a particular surface, markings will start to crack and adhere poorly to the pavement.
The effectiveness of pavement markings is also determined by their reflectivity. To meet reflectivity requirements, glass beads are dropped onto paint markings during application. The minimum requirement for reflectivity after application is lower due to expected wear and tear of a surface yet must exceed a minimum level to meet airport safety specifications. If reflectivity drops below the specified level, it must be repainted to meet FAA requirements.
MnDOT tests the effectiveness of markings around the state through the use of reflectometers (reflectivity sensors) and aerial software. This testing helps MnDOT make decisions about when to repaint, when to remove paint, and why paint might be deteriorating. Currently the state is taking measures to improve the process for applying paint.
The type of pavement markings required on an airport’s paved surfaces depends on the airport’s approach systems and design categories. For example, a threshold marking is required at airports with non-precision or precision approaches but is typically not required at airports with a visual approach. Paint requirements also depend on the runway design. For example, threshold markings are required on all runways with category C or D airplanes. Additional markings may be required in certain situations on taxiways or aprons as well, where a holding position marking or a delineating precision obstacle-free-zone (POFZ) marking, may be needed. Marking elements vary from airport to airport, so pilots must understand the different markings and which ones may be present at any location they visit. However, the FAA encourages uniformity in airport markings and signs from one airport to another to improve safety and efficiency.
—Nate Sievert is an airport operations program administrator with MnDOT Aeronautics. Adapted from an article that was originally published in Midwest Flyer.
