runway-friction reports and advisories

runway-friction reports and advisories

Runway-friction reports quantify the slipperiness of pavement surfaces. Runway friction is indicated by the Greek letter μ (mu). Its value ranges from 0 to 100, where 0 is the lowest friction and 100 is the maximum value that can be obtained. The lower the μ value, the less effective braking performance becomes and the more difficult directional control becomes. For frozen contaminants on runway surfaces, a μ value of 40 or less is the level when the aircraft braking performance starts to deteriorate and directional control begins to be less responsive. The report will identify the runway, the time of measurement, the type of friction-measuring device used, the μ values for each zone, and the contaminant conditions (e.g., wet snow, dry snow, slush, deicing chemicals). Measurements for each one-third zone will be given in the direction of takeoff and landing on the runway. A report should also be given when μ values rise above 40 in all zones of a runway previously reporting a μ below 40. Airport management should initiate a NOTAM (D) when the friction-measuring device is out of service. NOTAM (D) is a type of NOTAM (notices to airmen) that indicates information about movement areas.

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