Study on Brake Efficiency Airworthiness Requirements and Verification of Transport Category Aircraft

Braking efficiency is one of the key indicators for evaluating the performance of braking systems on transport category aircraft. The value of braking efficiency is directly related to the safety of aircraft deceleration processes, especially during landing, and it is also critical for civil aircraft operators to improve operational efficiency on routes. This paper presents the airworthiness regulation requirements related to braking efficiency, requirements for aircraft wheels and tires, requirements for runway pavement types, major sources of contaminants, and specific requirements for simulating wet runway conditions using different contaminants. This paper analyzes effective methods for calculating braking efficiency, including the pressure method, torque method, and slip ratio method, and introduces the approaches for acquiring data of relevant parameters. Combining experience from braking efficiency verification work, the paper demonstrates the specific test procedures for the actual measurement of braking efficiency. Based on measured data such as braking pressure, wheel speed, and aircraft speed during braking, as well as the wheel dimensions and rotational inertia of wheels and brakes, the specific braking efficiency values under different calculation methods are derived. The paper compares the differences in braking efficiency values obtained by various calculation methods for similar braking processes, analyzes the causes of these differences, and demonstrates that the accuracy of braking efficiency calculated by different methods is acceptable. Additionally, the same calculation method is applied to compute the braking efficiency of multiple braking deceleration processes, which demonstrates that the method has good repeatability and can be stably used for braking efficiency calculation. This verification method provides a reference for the certification work to ensure that the braking efficiency of transport category aircraft complies with airworthiness and performance requirements.