Samuel Gosnell Tucker

Docket No. FAA-2010-0684; Directorate Identifier 2010-CE-031-AD I have comments and suggestions for improvement on AD 2010-14-15. I believe that the inspection required as compliance, accomplished per MB No. L-13 / 109a, is inadequate to detect cracks in multiple layers of structure of the spar cap splice. The inspection per the AD note requires a 10x inspection, but no details are given to require any specialized viewing equipment. Due to focal distance limitations and limited access from the wing root, it will be difficult if not impossible to do a thorough inspection of the critical area using just a magnifying glass. At a minimum, a high magnification borescope with working length equal to or better than the 500mm inspection area should be required. Even using proper equipment, the inspection will be limited to visible surface area of a multi layered structure. Open hole eddy current of the critical fastener holes would provide much better inspection coverage. It would detect cracks in all layers, not just on the visible surface, and would find cracks smaller than those visible even with 10x magnification The AD as written requires reporting per the MB. Due to the requirement of the MB to compare operations to Average Operation Conditions, this AD as written has the possibly unintended effect of grounding gliders not within the averages, pending a manufacturer’s review. The problem with this is that it puts operators at the mercy of the manufacturer and on their timetable. In addition, no provision is given for repetitive inspections. No hard time limits are given for life limits on parts. I suggest that most of the provisions of GFA ( Glider Federation of Australia) AD369 (attached) be incorporated as compliance for this AD. This would give hard time limits to components, instead of relying on an arbitrary average and Manufacturer’s approval for continued operation. The Australian AD specifies hard time replacement of the carry though at 5000 hrs, and replacement of the wings or repetitive open hole inspections as an alternative. AD 2010-14-15 as written has no hard time limits on gliders within Average Operation Conditions, It only does a one time visual inspection, with no repetitive inspections or life limits. It leaves it up to the manufacturer to establish continued service for gliders outside the average operations requirements, on an individual basis.. It does not provide inspection of all layers of the structure, and it does not specify special viewing equipment that would improve probability of detection. The AD should be redrafted to incorporate all of these provisions and it should add NDT requirements. The Austrailian GFA AD369 provides a good model of a working document that improves overall safety of the fleet while giving operators options to assure continued airworthiness without having to submit to the manufacturer for approval when averages are exceeded..