What is runway friction testing?

What is runway friction testing?

The GripTester is a Federal Aviation Administration (FAA) approved continuous friction measurement equipment (CFME) device. It evaluates runway pavement friction and identifies areas that may have experienced a loss in texture due to wear and rubber build-up.

How is runway friction measured?

Surface Friction Measurement Devices which detect surface friction are termed ‘Continuous Friction Measuring Equipment’ (CFME). Usually, CFME is towed behind a vehicle at a constant speed and a wheel fitted with a smooth tyre is fitted with equipment which can directly measure the friction encountered.

What does friction coefficient 45 in a runway report mean?

3. What does “Friction coefficient 45” in a runway report mean: Braking action good. 4.

What is porous friction course runway?

Porous Friction Courses (PFC) are open-graded, high air void, bituminous mixtures that are applied to pavement surfaces to improve skid resistance. In 1989, a PFC was used as an interlayer prior to placing a bituminous overlay on the bituminous runway at the Pekin Municipal Airport.

What is a friction test?

Coefficient of Friction (COF) testing is used for a variety of materials from lubricants, to films and household items (ceramic tiles) to determine the frictional characteristics of a material. …

What is runway braking action?

Braking action in aviation is a description of how easily an aircraft can stop after landing on a runway. If an air traffic controller receives a braking action report worse than good, an advisory must be included in the Automatic Terminal Information Service (“Braking Action Advisories are in effect”).

Is friction a fluid?

Fluid friction occurs between fluid layers that are moving relative to each other. This internal resistance to flow is named viscosity. In everyday terms, the viscosity of a fluid is described as its “thickness”. The less viscous the fluid, the greater its ease of deformation or movement.

What is an example of sliding friction?

Examples of Sliding Friction A child sliding down through a slide in a park. A coaster sliding against a table. A washing machine pushed along with the floor. The frame and the edge of the door sliding against one another.

What does a lower coefficient of friction mean?

The coefficient of friction, µ, is a measure of the amount of friction existing between two surfaces. A low value of coefficient of friction indicates that the force required for sliding to occur is less than the force required when the coefficient of friction is high.

What is runway friction coefficient?

Table: Friction coefficient for compacted snow and/or ice covered runways, from ICAO Doc 9137, Part 2, Table 4-1. The friction conditions of a runway should be expressed as “braking action information” in terms of the measured/calculated friction coefficient μ or estimated braking action.

What does a grooved runway mean?

Grooves are cut in the runway surface transversely to the pavement centerline and make a secondary contribution to drainage. Runway grooving provides a higher degree of contact between aircraft tires and the pavement surface under the condition of standing water.

Is a grooved runway considered dry?

NASA did find a disparity in stopping distance on a wet grooved runway for different aircraft types. In any case, the research showed that a grooved runway, with a moderate rain fall rate, or less, could be considered “effectively dry.”

When to start a friction survey at an airport?

When conducting friction surveys at 60 mph (95 km/h), the airport operator should start recording the survey 1,000 feet (305 km) from the threshold end and terminate the survey approximately 1,000 feet from the opposite end of the runway.

How is surface friction achieved on a runway?

Enhancement of surface friction where challenged by water contamination can be achieved by grooving a runway surface to aid more rapid water dispersal. Various specifications exist for grooving but most are the same as or close to the FAA version, which is 6mm (0.25 inches) deep and 6mm wide spaced at 38 mm (1.5 inches).

Where can I find guidance on pavement friction measurement?

Guidance on pavement friction measurement for aircraft operational purposes during winter weather and performance standards for decelerometers are found in AC 150/5200-30, Airport Winter Safety and Operations. 1-2. BACKGROUND.

Which is an alternative to grooving on a runway?

An alternative to grooving as a means of facilitating surface water dispersal is the laying of a Porous Friction Course (PFC) which allows water to pass vertically through the surface layer and then move horizontally clear of the runway beneath, but essentially parallel to the surface.