U.S. Air Force Efforts in Understanding and Mitigating the Effects of "NDI Misses" (Preprint)
Abstract
Recent events within the U.S. Air Force (USAF) have highlighted the reality that cracks large enough to be readily detected by non-destructive inspection (NDI) can be missed during in-service NDI actions. These so-called "missed crack" or "NDI miss" events may pose serious risks to the safety and integrity of aircraft structures. This paper will review USAF actions: 1) to understand the severity and ramifications of the NDI miss problem, 2) to minimize the probability that cracks will be missed, and 3) to mitigate the effects of undetected cracks. In this paper, the probability of detection (POD) concept will be described from the standpoint of the variables that govern the detectable crack size associated with a given POD. Examples will be presented that illustrate the ramifications missed cracks have on aircraft structural safety. A technique for estimating the probability distribution of missed cracks based on NDI findings (i.e., "found cracks") and on the knowledge of a specific NDI technique's POD capability will be described. In addition, a brief review of recent advances in NDI technologies and techniques designed to minimize NDI misses will be presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2007
- Accession Number
- ADA476857
Entities
People
- Alan P. Berens
- Charles A. Babish Iv
- James C. Malas
- Joseph P. Gallagher
- Lawrence M. Butkus
Organizations
- Air Force Research Laboratory