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« Last post by Bruce Byerly on November 29, 2025, 05:20:52 pm »
From DOM side:
Lekebis Russell
Aviation Safety Engineer (Airframe)
East Certification Branch
1701 Columbia Ave.
Atlanta, GA 30337
(404)474-5510
Lekebis.m.russell@faa.gov
In regard to the Airworthiness Concern Sheet, dated May 27, 2025, concerning AD95-13-02, SB218. We have been paying particular attention to the visible structures in Fuselage Stations 386, 409, 429, & vertical stabilizer skins since early 2018 at each annual/150 hour inspection. This includes more than 50 models of Twin Commander’s ranging from 690A’s through 695B aircraft and found no cracking in the structure that is visible through inspection panels and access through the aft fuselage. The inspections have been performed with a mirror & flashlight and not non-destructive testing methods. There are areas in the vertical stabilizer structure above the repair, part 2, of SB218 that are not visible. We do inspect the outer skins, rivets and structure above the repair to the best of our abilities with no defects noted. We also still perform the bolt torque check at FS409.56 per SB206 that we believe to be essential to prevent cracking.
We do have several Twin Commanders that have a 5” diameter inspection panels installed on the right-hand side of the vertical stabilizer above the repair from part 2 of SB218 through an engineering order from GTEC. All the areas above the repair have been visibly inspected with no defects noted.
We have 2 aircraft that we maintain that still require the 500 hr inspection of the tail because part 2 of SB218 has not been complied with. One is a 690C, and the other is a 695A. Both aircraft had no cracks or defects noted at the last 500 hr inspection. All the aircraft we maintain are 91 and a few 135 operators.
In conclusion, I am not saying there is not a cracking issue in the fuselage stations noted in the Airworthiness Concern Sheet that requires paying particular attention during inspection process. Adding the 5” inspection panel above the repair from part 2 of SB218 would help in the inspection process of the vertical stabilizer. We are not seeing the cracking issue the Forest Service aircraft are experiencing in our Part 91 and 135 operators. If you have any questions or concerns, please feel free to contact me.
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