Statement of Ronald Ridenour

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Statement of Ronald Ridenour 1. I submit this Statement in support of the letter from the Soaring Society of America of December 22, 2025 (the “SSA Comment Letter”). That letter provides comments on a proposed Piper PA-25 Airworthiness Directive identified as follows (the “Proposed AD”): Docket No. FAA–2025–3990; Project Identifier MCAI–2025–00097–A Document Citation: 90 FR 51610 Document Number: 2025-200-84 Publication Date: 11/18/2025 RIN 2120–AA64 2. I am a graduate of Purdue University, where I was awarded a degree in aeronautical and astronautical engineer. Since 1978I have been a licensed Airframe and Powerplant Mechanic, No. 1985138 with Inspection Authorization. I also hold pilot ratings in airplanes and gliders, including flight instructor (airplane and glider), and ATP. I also hold type ratings for several Boeing transport aircraft, and other turbine powered aircraft. I served as a pilot and line check airman for United Airlines prior to retiring in 2017. Since 1975 I have served as a Designated Pilot Examiner for the FAA for ratings for airplanes and gliders. For 18 years I owned and operated a glider flight school in the Chicago area. 3. I have for many years regularly perform maintenance and repair work on airplanes and gliders, including the Piper Pawnee PA-25 that has been owned by the Chicago Glider since 1991. I have done so for 47 years. I also sometime serve as a tow pilot, flying the Piper Pawnee in glider tow operations at the Chicago Glider Club, which is located in Minooka, Illinois. I am currently the President of the Chicago Glider Club. 4. Among other maintenance and repair work on the PA-25, in 2021 I assisted Donald Kroesch in replacing the ceconite fabric on the wing covers on the Chicago Glider Club’s PA-25, 2 and did the pre-recover inspection of the wings before the new fabric was installed. I am very familiar with the structure of the Piper PA-25 Pawnee wing, and other areas of the aircraft. 5. As an A&P with inspection authorization, I have done hundreds of annual and 100- hour inspections on airplanes and gliders. I am well acquainted with the risk of corrosion in aircraft. I review for corrosion as part of such inspections that I conduct. I know what corrosion looks like and have found it on occasion in aircraft that I have inspected. 6. I have reviewed the photos of three South American PA-25 crashes included in the SSA Comment Letter as Figures 1-3. Each shows visible evidence of corrosion that should have resulted in grounding the aircraft and repairing or replacing corroded components. Figure 1 shows visible corrosion in discoloration located on the interior to the spar flange. Figure 2 shows visible corrosion on the left portion of the spar, which is brown in color and obviously corroded. Figure 3 shows visible corrosion as evidenced by the brown color of the metal. 7. I have read the SSA Comment Letter and agree with in its comments concerning the difficulties and expenses that would result from implementing the Proposed AD. I have also read Donald Kroesch’s Statement in support of the SSA Comment Letter. I agree with his description of the difficulties, costs and risks of damage to the wing spar from implementation of the Proposed AD. 8. I believe the hourly labor estimates for implementing the Proposed AD as contained in the SSA Comment letter are fair and reasonable. 9. I am acquainted with hourly labor rates for aircraft technician in the Chicago area. They range from $120 to $245 per hour. 10. I also agree with the SSA Comment Letter that the use of a 3 mm borescope to inspect the front spar and its connection to the leading-edge sheet metal is a far better, less