Cessna 210 Centurion Spar Inspection

               Cessna published SEL-57-01 after receiving reports from the Australian CASA of cracks in the lower spar inboard of wing station 43. This service letter requires a repetitive inspection of the area at a 100 hour or annual interval, whichever occurs first on all cantilever wing Cessna 210’s. When this service letter is accomplished, a report form must be returned to Cessna reporting the airplane’s condition: cracked or un-cracked.

             The Federal Aviation Administration published AD2012-10-04 May 21st, with an effective date of June 5th, 2012, requiring a one-time inspection and report of findings to the FAA, Wichita ACO. Cessna encourages continued compliance with the service letter inspection interval and reporting in addition to compliance with the AD. 
                    Cessna is working with the FAA to provide terminating action to this issue while maintaining the safety and viability of the 210 fleet. Terminating action in this instance can be a life-limit and part replacement program, or a damage tolerance-based inspection program.
                Cessna is moving forward with an engineering study to develop a damage tolerance inspection program which if successful will allow airplanes to remain in-service without spar replacement.
                  This program will include a flight strain survey, material tests of the spar cap and analysis of the data to complete crack growth models; and component testing to verify the residual strength capability of the spar cap with a crack.
             Since publication of this service letter, two additional airplanes have been found with a lower spar cap cracked. A summary of the incidents appears in the table below.