Operational Airworthiness
Cessna 182S, 206H and T206H Right Wing Spar Cap Stiffeners
Purpose
This notice is to advise owners of Cessna 182S, 206H and T206H models, that some Cessna aircraft identified within a serial number range, were inadvertently manufactured with right wing spar cap stiffeners made of 0.100 inch thick material [hereafter referred to as "thin spar cap stiffener"] instead of 0.125 inch thick material [hereafter referred to as "correct spar cap stiffener"]. Although Cessna has determined that a thin spar cap stiffener on these models still meets the type design strength requirements, aircraft with the thin spar cap stiffeners are not eligible for modifications which require weight increases above the maximum takeoff weight limits specified in their respective Transport Canada (TC) and Federal Aviation Authority (FAA) aircraft Type Certificate Data Sheets (TCDS).
Background
Cessna issued Special Service Project SSP00-57-01, "Right Wing Spar Cap Stiffener Inspection" dated 11 September 2000, requiring the inspection of Model 206H and T206H wings to determine the thickness of the spar cap stiffener. Once the inspection is complete, SSP00-57-01 requires the completion and return of a form, which reports the spar cap stiffener thickness. Spar assemblies found to have been manufactured with thin spar cap stiffeners are to be replaced by Cessna on an agreed schedule with the owner/operator. Cessna has committed to tracking suspect airplanes to determine which have thin spar cap stiffeners, and which have been brought up to type data configuration [by replacing the thin with the correct spar cap stiffener] or were originally equipped with the correct spar cap stiffener from the factory. Although the same problem exists on the Cessna 182S, similar inspection action has not been initiated by Cessna since there are no known supplemental type certificates (STCs) for this aircraft that would raise the gross weight of the aircraft (ie. floats).
Both TC and the FAA have taken action to update each aircraft TCDS to identify those serial numbered aircraft suspected of having thinner spar cap stiffeners as follows:
- Note 4 in the Canadian TCDS A-212 (FAA TCDS A4CE), for both the 206H and T206H models, states that the serial numbered aircraft listed "are not eligible for any weight increases above the approved maximum takeoff weight limit of 3,600", and
- For the Cessna 182S models, Canadian TCDS A-204 Note 2 (FAA TCDS 3A13, Note 5) states that the identified serial numbered aircraft are "not eligible for any weight increase above the approved maximum takeoff weight limit of 3,100 pounds".
In discussions with the FAA, no mandatory corrective action is being proposed to remove these thin spar cap stiffeners from affected airplanes.
Recommended Practice
Although the affected aircraft are identified on the applicable TCDS, Transport Canada is concerned that because the wings are not serial numbered, wing changes in the future may lead to a wing with a thin spar cap stiffener being placed on an aircraft not currently identified in the TCDS as being ineligible for a weight increase above the approved maximum takeoff weight limit. Also, because the FAA did not mandate the Cessna corrective action, some operators may choose not to replace the thin spar cap stiffeners if they are not intending to install floats or other STCs that increase the aircraft weight above the limit specified in the TCDS.
Therefore, prior to the installation of any STC that would increase the maximum takeoff weight of the aircraft above the limit specified in the TCDS, owner/operators are advised to confirm that their aircraft is not one of the serial numbers affected by this weight increase restriction, or if it is, that the modification is coordinated through TC in accordance with Canadian TCDS instructions. When importing or purchasing these Cessna models, logbooks should also be reviewed to identify any wing replacements and, to verify, to the extent possible, the history of any such wing replacements. If the origin of the replacement wing is in doubt, inspection of the spar cap stiffener in accordance with Cessna SSP00-57-01 should be conducted to verify the actual thickness of the spar cap stiffener.