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sample size

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FAA Issues Draft “Sample Size” Advisory Circular that Would Apply to PMA, STC, and RS-DER applications

The FAA has issued for comment a draft Advisory Circular focused on sample size for statistical analysis in PMA applications. As many of you remember, there was a draft on statistical analysis issued several years ago. MARPA objected to that draft because it implied that every PMA application needed to be based on statistical analysis, … Continue reading

FAA Issues Statistical Analysis Guidance – Are You Testing Enough Parts?

The FAA has issued new guidance for how to use statistics in your PMA and STC applications. They have also set minimum sample sizes that seem unrealistically high for many parts. The guidance is limited to sample sizes for engine parts and APU parts, but it sets a precedent that could be followed for other parts. Continue reading