Airworthiness Certification of Fe-Si3N4-graphite Brake Composites for Military Aircraft

Metal matrix hybrid composites are usually preferred for high energy aircraft (1-10 MJ) brake pads (HEABP) applications. The report focuses mainly on the evaluation of the wear and braking performance of the composite for the military aircraft applications. In this paper, the design and processing of a typical HEABP composite have been discussed in detail. The airworthiness qualification tests for the HEABP and the brake units are outlined with details. Also, brake testing parameters calculations derived from the typical aircraft data are presented for both the laboratory and full scale dynamometer tests. A case study of Fe-Si3N4- graphite composite pads is presented to exemplify the steps involved in the design, development, and airworthiness certification of HEABPs for the 8 MJ energy military aircraft. From the microstructure and wear surface morphology analysis and the results of brake performance parameters, functional tests and aircraft trials, it is concluded that the Fe-Si3N4- graphite composite has a minimum life of 200 normal energy landings with excellent braking performances.