scope:

Description of Driving Event:

The shuttle orbiter right hand inboard brake failed during the STS-7 landing, even though there was very little braking action. A post-flight tear down and evaluation of the brakes determined the cause of the failure to be defective retainers (washers), which hold together the carbon lining and the carrier plate. These retainers are made from Titanium/Zirconium/Molybde-Num (TZM), which is very resistant to high temperature and very brittle. Numerous cracked retainers were found during the inspection. The cracks, in many cases, were not perceptible with the human eye and were only detected by Eddy Current inspection. The retainers were visually inspected and replaced as required before the STS-7 flight. As corrective actions, the supplier implemented the use of a different riveting tool to minimize cracks and a change in the inspection procedure to include a 100% use of the Eddy Current inspection technique.