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Runway Friction Tester

NAC-DFT™ Runway Friction Tester

The NAC-Dynamic Friction Tester (NAC-DFT™) is an aerodynamic tow-behind continuous friction measurement device (CFME), approved for use on airport runways by the FAA. The NAC-DFT™ is built in the United States and is used by airport authorities around the world.

    The NAC-DFT™ complies with ASTM E2340 Standard Test Method for Measuring the Skid Resistance of Pavements Using a Continuous Reading, Fixed-Slip Technique. It creates and measures the frictional force between an ASTM E1551 test tire operated at a 12% slip while towed across the runway surface.

    The device is optimally suited for both summer- and winter-time testing.

      Friction is key to runway safety

      Regular measurement of runway friction is essential to safety. The FAA Advisory Circular on runway friction states:

      Regardless of pavement type or surface treatment, runway friction characteristics will change over time depending on type and frequency of aircraft activity, weather, environmental issues, and other factors. In addition to ordinary mechanical wear and tear from aircraft tires, contaminants can collect on runway pavement surfaces to decrease their friction properties. Contaminants such as rubber deposits, dust particles, jet fuel, oil spillage, water, snow, ice, and slush all cause friction loss on runway pavement surfaces. Rubber deposits occur in the touchdown areas on runways and can be quite extensive. Heavy rubber deposits can completely cover the pavement surface texture thereby causing loss of aircraft braking capability and directional control when runways are wet.

      As to the frequency of testing, the FAA advises: “Every runway for jet aircraft should be evaluated at least once each year. Depending on the volume and type (weight) of traffic on the runways, evaluations will be needed more frequently, with the most heavily used runways needing evaluation as often as weekly, as rubber deposits build up.”

      Working Principle

      The NAC-DFT™ is a portable CFME testing trailer able measure surface friction, drag, and travel distance, through contaminants accounting for longitudinal and lateral acceleration at 12% slip braking. The NAC-DFT™ is completely self contained with on board power supply, control unit, and water tank. The DFT has a high profile and long chassis to facilitate ease of movement and measurement at up to 100 km/h (60 mph).

      The NAC-DFT™ collects reliable friction values continuously and the results are displayed graphically. The data collection software uses touchscreen controls for user convenience and runs under the Microsoft Windows operating system. Friction results can be automatically displayed in either Mu or RCR values. Data can be automatically displayed in an easy-to-read bar chart that displays results for specific runway sections such as touchdown, midfield, and rollout. The software includes contaminant type drop down menu listing over 14 different types of contaminate which align with the Notice to Air Missions (NOTAM) reporting system. All data collection is transmitted wirelessly or via direct serial cable to the tow vehicle laptop or tablet.

      The device features state-of-the-art precision engineering and is the leader in reliability and environmental-friendliness. Its built-to-last design dramatically reduces maintenance and operating expense.

          Industry Standards

          • ASTM E2340 Standard Test Method for Measuring the Skid Resistance of Pavements and Other Trafficked Surfaces Using a Continuous Reading, Fixed-Slip Technique
          • ASTM E1551 Standard Specification for a Size 4.00-8 Smooth Tread Friction Test Tire

          NAC-DFT™

          A CFME approved by FAA for use on airport runways.