Prevailing Cultural / Organizational Factors

Quality Control Process Lapse

Illustration of the effect of misaligned counter bore
Illustration of the effect of misaligned counter bore - ATSB accident report

Rolls-Royce discovered that a number of oil feed stub pipes had been incorrectly manufactured (non-concentric counter bores), and delivered on engines. Other oil feed stub pipes with non-concentric counter bores were also found in the factory, prior to installation on engines. A statistical analysis was performed using the not-yet- delivered parts, and the results of that analysis were extrapolated to include the parts already in service. Based on the results of that analysis, it was determined that the oil feed stub pipes that were already in service did not need to be recalled or replaced.

Investigators determined that an expert review of the nonconformance issues had not been performed, nor was it required for review of what was termed ”retrospective concession applications.” Further, investigators noted that the manufacturer’s processes did not specify when the Chief Engineer and Business Quality Director approvals were required. Both of these items were identified as safety issues by the investigators. Investigators also noted that by not providing the opportunity for the Chief Engineer or Business Quality Director to review and approve the analyses associated with retrospective concessions, it prevented those parties from assessing the potential impact on the in-service fleet.

Manufacturing Process Lapse

Finally, investigators stated in the accident report that since the manufacturing errors took place over at least three years, it was likely that, “…… a culture existed ……… that considered that not strictly adhering to the nonconformance management procedures in the group quality procedures was a viable form of behavior. Specifically, it was considered acceptable to release parts with undeclared non-conformances that were considered by at least some of the inspectors to be ‘minor’. “

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