Failure analysis of a main wheel brake assembly of a Royal Malaysian Armed Forces (RMAF) aircraft

This paper presents the failure analysis of a broken main wheel brake assembly of a Royal Malaysian Armed Forces (RMAF) aircraft. The analyses performed included visual and macroscopic observations, together with fractographic and chemical composition analyses. Based on the analyses conducted, shrinkage porosities and intergranular crack propagation along the dendrite boundaries were revealed. Scanning electron microscope (SEM) analysis found a number of voids in between the dendrite arms as evidence of shrinkage porosities that lead to material separation and crack propagation before the component fractured. It was concluded that service life and environmental factors caused the crack to initiate from the porosities, which propagated intergranularly and created connections between each other. This activity weakened the structure of the composition and hence, the fracture occurred once the crack propagation exceeded its critical limit