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Runway friction testing plays a crucial role in maintaining airport safety. It helps assess runway conditions before and after rubber removal, ensuring optimal friction levels for landing and takeoff. This guide will walk you through the step-by-step process of how to conduct runway friction testing, from preparation to evaluating the results.
Before conducting any friction test, it’s essential to close down the runway. You can’t have air traffic landing or taking off during the test. A typical friction test takes around an hour, and continuous friction measuring equipment (CFME) can be quickly removed in case of an emergency landing.
Once the runway is clear, ensure your CFME setup is ready. Most CFME units are trailer-mounted, towed behind a truck that pours water in front of the testing tire to simulate rainy conditions. The water forms a 1mm layer on the runway surface, mimicking wet weather. Make sure the water tank is full, and calibrate the CFME to ensure accurate readings.
Step 2: Perform the Friction Test
The friction test involves four runs at different speeds and distances from the centerline of the runway. These runs simulate real-world conditions for aircraft during takeoff and landing:
- 10 feet from the centerline at 40 mph
- Tests the microtexture of the runway, simulating conditions for narrow-body aircraft or small to medium-sized planes during taxiing or early takeoff.
- 10 feet from the centerline at 60 mph
- Evaluates the macrotexture, measuring high-speed grip for narrow-body aircraft just before takeoff or as they land.
- 20 feet from the centerline at 40 mph
- This test checks microtexture further from the centerline, where wide-body aircraft (such as Boeing 777s or Airbus A350s) tend to cause rubber buildup.
- 20 feet from the centerline at 60 mph
- Similar to the above, this run assesses macrotexture for wide-body aircraft, specifically looking at the areas of the runway used during high-speed landings and takeoffs.
Each test requires acceleration space: 500 feet for the 40 mph tests and 1,000 feet for the 60 mph tests.
Step 3: Interpreting the Results
Each 500-foot segment of the runway is measured, and the continuous friction measuring equipment (CFME) provides a friction coefficient value, which indicates how well the runway surface grips the testing tire in wet conditions. These readings are recorded by an on-board computer, allowing the operator to easily store the data on a laptop or hard drive for further analysis.
The friction data collected can be analyzed using specialized software that often comes included with the purchase of CFME devices. This software helps generate reports and visualize the results, making it easier for airport personnel to assess runway conditions and determine when rubber removal is necessary. The following table can help you interpret the results from your runway friction test, depending on the CFME you use:
Friction values fall into three categories:
- Above Maintenance Planning Value: Friction is adequate, but the runway should be monitored.
- Below Maintenance Planning Value: Rubber removal should be planned soon.
- Below Minimum Value: Immediate rubber removal is required for safety.
If one 500-foot segment returns a low reading, it might not be a cause for immediate concern. However, if three adjacent segments are below the maintenance threshold, rubber removal should be conducted as soon as possible. We at Avion hope this guide was useful in assisting with your successful runway friction testing.
Step 4: Conducting Rubber Removal
If runway friction testing shows low grip levels due to rubber buildup, rubber removal should be performed promptly. Avion50 is highly effective, removing rubber without damaging runway markings, joint seals, or the pavement surface itself. It’s a safe, environmentally friendly solution that extends the lifespan of your runway, and costs only pennies per square foot. Contact us here and secure a sample today to test Avion50 against your current rubber removal method!