Braking performance of commercial airplanes during operation on winter contaminated runways

The relation between descriptive information of runway surface conditions and the braking performance of commercial airplanes was investigated at two Norwegian airports during the winter seasons 2008/2009 and 2009/2010. Of the 24,928 analyzed landings, 885 landings (3.6%) took place where the airplane stopping capability was limited by the frictional conditions on the runway. For these landings the airplane braking coefficient (μB) was determined using the Boeing Airplane Braking Performance Model. The average μB was clearly sensitive to the reported type and spatial coverage of contamination; however there exists a large variability between individual landings on the same reported conditions. To a lesser extent, the average μB was sensitive to the amount of precipitation accumulated since the last runway inspection/snow clearing. The results of this study are relevant for ongoing initiatives to interpret descriptive information on runway surface condition in a scale ranging from “poor” to “good”.