Following an assessment of historical data, the aircraft manufacturer, Textron Aviation, replaced a flight hour based repetitive eddy current inspection for cracking of the carry-through structure with a three-yearly visual corrosion inspection for all operation types. This significantly limited the opportunities to identify fatigue cracking within the carry-through structure of low-level survey aircraft prior to a crack reaching a critical size.
On 24 June 2019, Textron Aviation (Textron) released mandatory service letters SEL‑57‑06 and SEL‑57‑07 for the Cessna 210 (C210) and Cessna 177 (C177) aircraft. These service letters required a one-off inspection of the structure and communication of inspection findings to the manufacturer.
On 4 November 2019, following the receipt and analysis of results from the previously released service letters, Textron released updated service letters SEL-57-08 for the C210 and SEL-57-09 for the C177.
Textron subsequently advised the ATSB that it was undertaking a fatigue analysis of the C210 wing spar carry-through. This analysis included information from the VH-SUX accident and inspections of other aircraft and aimed to determine whether a modified inspection program or life limit was necessary. Textron also advised that work on a certification program to install a new spar in the C210 with an updated configuration and material was ongoing.
The ATSB acknowledges the safety action taken by Textron and welcomes its ongoing efforts to address this safety issue. However, the ATSB remains concerned by the indefinite nature of the proposed analysis and certification program. As such, the ATSB issues the following safety recommendation to Textron to take further action to address this safety issue.
The Australian Transport Safety Bureau recommends that Textron Aviation takes further safety action to address the risk of fatigue cracking within the carry-through structure of Cessna 210 aircraft operating in low-level geophysical survey roles.
On 21 February 2020, the FAA adopted airworthiness directive (AD) AD 2020-03-16 for all Cessna model 210G, T210G, 210H, T210H, 210J, T210J, 210K, T210K, 210L, T210L, 210M, and T210M aircraft. This AD required:
On 11 May 2021, the FAA issued a notice of proposed rulemaking for a one-time inspection for 210N, 210R, P210N, P210R, T210N, T210R, 177, 177A, 177B, 177RG, and F177RG models. On 25 June 2021, the consultation period for the notice of proposed rulemaking closed. At the time of writing, the FAA was reviewing the received comments.
On 12 July 2019, the Civil Aviation Safety Authority (CASA) released Airworthiness Bulletin AWB 53-011 providing additional information to assist with managing the airworthiness of Cessna 210 (C210) and Cessna 177 (C177) wing carry-though spar structures.
This bulletin recommended that operators and maintainers of C177 and C210 aircraft with cantilevered (unstrutted) wings undertake actions including:
Note: CASA recognises that some maintenance programs already require compliance with these Cessna service letters.
