The SSA would like to update members and commercial operators on the status of the SSA review and response to the November 18 proposed rule by the FAA regarding the Pawnee wing and spar inspections for corrosion and front spar cracking. We have an SSA committee that is focused on responding to the NPRM and is actively working with Anthony Smith, Engineer Specialist with Gliding Australia. Anthony has furnished the committee with draft copies of his PA-25 Front Spar Stress and Fatigue Analysis reports developed for The Gliding Federation of Australia, Inc. These excellent reports will be utilized as supporting documents for our response and recommendations for an alternate approach to the FAA proposed AD.
Our focus establishes the significant difference between stress and fatigue created by Agricultural use and the greatly reduced stress and fatigue on Pawnees operating solely for Aerotow as a result of lower gross weight operations and flight profile. Of particular focus is the need for following inspections being based on flight hour extensions or elimination as a result of a satisfactory spar inspection or spar replacement supported by Fatigue and Stress Analysis. Additionally, we are recommending visual inspections for crack detection utilizing a high-resolution borescope capable of imaging the leading-edge attachment screw holes between the flange and the spar web as opposed to initial and reoccurring leading-edge eddy current inspections.
The committee has requested an extension to the NPRM response period based on the complexity of the proposed action as well as the holidays within the response period effectively reducing our time for analysis and response.
We have encouraged SSA Clubs and commercial operators to respond to the NPRM as well. A general response outline is available for reference by contacting rick.hoffmann50@yahoo.com.
One of our committee members, Ken Sorenson, has published a request for supporting information on the SSA Towplanes Google Groups asking for information on your Pawnee. Please review this request and respond as soon as possible as we are trying to create a model of our Pawnees aerotow histories and the potential economic impact on club’s operations and revenue generation.