Research On Aircraft's Towing And Parking Safety Technology

Aviation safety is an everlasting subject of civil aviation and the basis of the civil aviation's survival and development.As an important part of aviation safety,the aircraft ground safety is always the focus of govermental supervision.When airplanes are parking or being towed,bad weather,environment,unexpected events,human error and other factors may cause ground accidents with casualties and property loss.Although the results of these accidents are not as serious as results of fatal aircraft crashes and the impacts of these accidents are not very huge,the frequency of these accidents is so high that they should be paid enough attention.In view of this,this paper is to study the safety of aircraft ground traction process and ground parking under normal operating conditions.The main research contents include:1)Based on the Adams simulation platform,the dynamic simulation model of the aircraft traction system was established,and the traction loads and the landing gear parts of the traction system were analyzed by simulating.The influence of the non-matching traction system on the load was analyzed,and meanwhile the failure mode of the drag arm under the action of the load on the front landing gear of the B737-800 airplanes was analyzed.2)In order to improve the present situation that towing loads are uncontrollable and safety can not been maintained in special conditions or under non-normal operation,the idea of controlling the towing loads was proposed and a new type towbar with controllable shock absorption was developed.On the basis of active or passive controlling means,the towbar can change its oneself stiffness and damping in real time.After the completion of the relevant parameters,the new type towbar was simulated and the results showed that this new type of towbar could effectively reduce the towing overloads.3)Based on the investigation for the aircraft manufacturers including Boeing and Airbus,wheel chock manufacturers,airlines and airports in China and abroad,the formulae of the forward lift,forward thrust and cross thrust of wind were set up according to the test data of B737-800 airplanes on the ground,and the load distribution to aircraft tires were gotten by analyzing the forces on aircraft and calculating the gravity center of aircraft.In consideration of wind forces,ground conditions,brake status and maximum wind speed permitted,the restraint efficacy and the failure modes of rubber and medal chocks popularly used in China have been thoroughly studied by using the self-clocking principle of friction cone when the airplanes can be restrainted by chocks under extremely high wind conditions.4)The finite element method was used to analyze the two kinds of metal chocks,and the new parameter of “coefficient of pushing away” was put forward to measure restraint efficacy of wheel chocks.The advantages and disadvantages of the two metal chocks were compared and the topological optimization of metal chocks was also carried.In addition,the paper put forward the optimized design schemes for rubber and metal chocks with high comprehensive performances according to the restraint efficacy and failure modes and convenience to use.