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

Details

• Corporate Creators:
  United States. Department of Transportation. Federal Aviation Administration
• Subject/TRT Terms:
  Airplanes Airworthiness Airworthiness Directive 93-21-12 Corrosion Cracking Forward Spar Fuselage Attachment Fitting Inspection Maintenance Nondestructive Inspection Nondestructive Tests Piper PA-25

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• Publication/ Report Number:
  DOT/FAA/AR-95/51
• DOI:
  https://doi.org/10.21949/1404004
• Resource Type:
  Research Paper
• Geographical Coverage:
  United States
• Corporate Publisher:
  United States. Department of Transportation. Federal Aviation Administration
• Abstract:
  The Federal Aviation Administration's (FAA's) Aging Aircraft NDI Validation Center (AANC) at Sandia National Laboratories applied two nondestructive inspection (NDI) techniques for the inspection of a Piper PA-25 forward spar fuselage attachment fitting. A review of two PA-25 accidents revealed the susceptibility of these fittings to corrosion and corrosion-induced-cracking. It was believed that corrosion was a precursor to the cracking and hence this effort focused primarily on developing techniques to detect the material thinning. The nondestructive testing techniques attempted were based on radiography and ultrasonics. Each of these techniques did reveal material thinning in the attachment fitting samples from a PA-25 aircraft. Efforts to detect cracks in the attachment fitting using NDI proved unreliable due to 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. Document downloads as a Word file using WINWORD.EXE.
• Format:
  DOC
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:7cc907a292bf4fc2d0fe78763cb0a1138ad0e818399215dec6583334b44e9623212c1153939f456a3c46c257625cef123c4998edb7a0c9d16f631c49914d5628
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/12527/dot_12527_DS1.pdf
• File Type:
  [PDF - 369.21 KB ]