Influence on veer-off behavior of aircraft hydroplaning due to transverse uneven water accumulation

Accumulated water film on the pavement is unevenly distributed due to several factors, which may lead to an aircraft veer-off accident. The single index of water film thickness lacks the ability to characterize the water film distribution condition. In this paper, a theoretical model of the deviation behavior of aircraft hydroplaning was established. A hydroplaning simulation of an aircraft wheel group was carried out on the basis of the American full-scale test result of pavement loading. The transverse water film uneven distribution was quantified section by section. The differences in the frictional effect between both sides of aircraft wheel group were compared. It was suggested to use a new type of evaluation index called the critical length of unevenly distributed water film. The rationality and applicability of such an index were verified through a correlation study between critical length and aircraft taxing performance variation by using ADAMS-based kinematic analysis. The result indicated that notable differences exist between the time-history curve of the frictional effect between both sides of the wheel group in the case that the aircraft lands on the pavement with a transversely unevenly distributed water film. The entire landing procedure raised the likelihood of a veer-off mishap because asymmetric deviation forces constantly impact the aircraft's taxing performance. The critical length of uneven distributed water film derived from three study cases were merely 6.6% differed from theoretical results. The proposed evaluation index may take the accumulative impact of deviation forces due to transversely unevenly distributed water film into consideration, which may provide useful reference for take-off and landing safety protection and water distribution control on the pavement.