Nondestructive Inspection of Piper PA-25 Forward Spar Fuselage Attachment Fitting

摘要

The Federal Aviation Administration's (FAA's) Aging Aircraft NDI ValidationCenter (AANC) at Sandia National Laboratories applied two nondestructive inspection (NDI) techniques to inspect a forward spar fuselage attachment fitting of a Piper PA-25 aircraft. The NDI techniques used were based on radiography and ultrasonic testing methods. Each of these techniques did reveal material thinning in the attachment fitting samples cut from the PA-25 aircraft. Efforts to detect cracks in the attachment fitting using NDI techniques proved unreliable due to the geometry constraints and were therefore abandoned. Based on the results of these experiments, an ultrasonic test procedure was subsequently developed for identifying the material thinning and is appendixed to this report. This procedure has since been incorporated by the FAA into a revision of Airworthiness Directive 93-21-12. The Federal Aviation Administration's (FAA's) Aging Aircraft NDI Validation Center (AANC) at Sandia National Laboratories applied two nondestructive inspection (NDI) techniques to inspect a forward spar fuselage attachment fitting of a Piper PA-25 aircraft. The NDI techniques used were based on radiography and ultrasonic testing methods. Each of these techniques did reveal material thinning in the attachment fitting samples cut from the PA-25 aircraft. Efforts to detect cracks in the attachment fitting using NDI techniques proved unreliable due to the geometry constraints and were therefore abandoned. Based on the results of these experiments, an ultrasonic test procedure was subsequently developed for identifying the material thinning and is appendixed to this report. This procedure has since been incorporated by the FAA into a revision of Airworthiness Directive 93-21-12.