Wing Inspections Proceeding on the T-6/SNJ Fleet
The North American T-6/SNJ fleet is complying with Airworthiness Directive (AD) 2005-12-51, which requires that paint be removed and a fluorescent dye penetrant be used to look for defects in the aircraft’s wing attach angles. The FAA has also approved an alternative means of compliance (AMOC) allowing eddy current inspection for defects. Each of these methods has its good and bad points.
Regarding the fluorescent dye penetrant method: Certainly attacking our aircraft with stripper is never a good idea. However, a stripping product that has come to our attention, RemovALL SV35PMA, by Napier Environmental, British Columbia, Canada (www.biowash.com), is an environmentally friendly product made specifically for the aircraft industry. It is available from Aircraft Spruce & Specialty and Wicks Aircraft Supply.
The eddy current method of inspection is much less invasive to the structure, however it is very operator-dependant for the correct results. We have had reports of NDT level 2 inspectors finding defects that turned out to be inspection stamps or scratches in the attach angle, but not a crack. Once a defect is found only a NDT level 3 inspector can change the findings.
Whatever method you use to comply with the AD, make sure that method is properly completed. If you do find cracks or corrosion please make the time to take a digital or film photograph and send it to NATA or EAA Warbirds of America. Either way, when the inspection is finished, make sure you complete the survey on EAA Warbirds of America’s website, www.warbirds-eaa.org, as to the result of your inspection.