In 2019, a T210M in Australia suffered an in‑flight breakup traced to a fatigue crack that began in a corrosion pit just 0.011 inches deep. That accident triggered a fleet‑wide look at the Cessna 210 and 177 carry‑thru spar, and what the FAA found became AD 2023‑02‑17.

The spar is a single‑load‑path structure made from 2014‑T6 aluminum, strong but vulnerable to intergranular corrosion. Of 211 Textron Model 177‑series inspections reported to the FAA, 120 showed corrosion or damage, and at least 14 spars were removed from service. Even “clean” airplanes can hide trouble.

‍What it requires: A visual inspection of the carry‑thru spar lower cap, followed by an eddy current inspection. Corrosion findings require blending or repair; all aircraft receive primer and CIC.

‍Field Notes: The eddy current inspection has two parts.

‍• Kick Area: Every affected airplane gets an unconditional ECI of the “kick” area, exactly where the fatal T210M crack initiated, regardless of what the visual shows. Because the lower cap is in compression during inspection, early cracks can stay closed and invisible.

• Blended Areas: Any area where corrosion was blended must also receive an ECI. A blended surface can look clean, but only ECI confirms that no subsurface cracking remains.

‍Reporting: Results must be submitted to the FAA within 30 days.

‍From the field: A 177 arrived with a log entry claiming compliance, but no CIC was listed, and no FAA report was filed under paragraph (k). That’s not compliance. The AD’s materials list is specific, and the logbook must reflect exactly what was applied. If it isn’t documented, it didn’t happen.

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