scope:

Description of Driving Event:

Part shortages, late engineering changes, and manufacturing difficulties have resulted in a number of minor differences between the structural test article (STA) and the ensuing flight article. Initially, the engineering intent was that the structural subassembly of these two vehicles would be identical from an engineering drawing standpoint. At the last minute, part shortages required the use of acceptable substitutes for the test article. These last-minute changes carried over to the flight articles, resulting in engineering configuration changes / part number changes for major subassemblies late in the manufacturing cycle, causing delays as the planning/manufacturing paperwork was reworked. Additionally, non-conforming detail parts that are acceptable for the STA only require additional engineering documentation to control their usage to test only if the next assemblies do not account for specific part number differences between flight and test. This again has caused delays in getting acceptable hardware installed on schedule.

Root cause: Failure to carry part number differences between the flight article and test article early in the design and planning phase.