The Statistics AC is going to be revised.
We have been working with the FAA to study the Advisory Circular (AC) 33-10, Statistical Analysis Considerations for Comparative Test and Analysis Based Compliance Findings for Turbine Engine and Auxiliary Power Unit Replacement, Redesign and Repaired Parts. We have pointed out a number of concerns with respect to this advisory circular in both our formal comments and in subsequent discussions with the FAA. These can be summarized as saying that the AC does not appear to get the FAA to where the FAA wants to be, and consequently will not appreciably contribute to safety.
The FAA has let us know that they will be rescinding the version of AC 33-10 that was published in late August. It must go through the internal FAA process so the rescission will not be immediate, but applicants should probably treat it as if it no longer existed because the text did not suit the FAA’s intended purposes.
This is not the end for statistics. The FAA still wants to provide useful guidance to the industry. But they have recognized that the current draft of the statistics AC is not what they want and have decided to take a step back and revisit the scope and intent of the AC. They plan to incorporate changes and solicit formal comments on the revised document in order to make sure that they meet their goal of creating a useful document that helps to move the industry towards our mutual safety goals. This will give everyone in the MARPA community an opportunity to contribute to the document.
This action reflects a joint efforts by the FAA and MARPA to understand the true impact of the guidance, and the rescission is a triumph of both good government and good industry efforts.