To: rjsquirrel
A tail rotor hub cracked, and that the crack progressed to fail the tail rotor, toss some blades and cause the crash. Conventional wisdom says that only time and experience (and crashes) will teach us how to eliminate all these critical component failures.
If a proper engineering program is initiated it will include Product Integrity analyses which includes an FMECA. The purpose of the FMECA is manifold in that it identifies all potential failure modes and the resultant effect of those failures. The FMECA also is used to create the troubleshooting procedures relative to the identified failures. The severity of the failure and its’ effect will identify to engineering and the test engineers what should be tested and what may have to be redesigned in order to eliminate the effect as well as the failure. A properly executed FMECA will encompass all of these elements. However in this case the FMECA was just executed.
