Amphibious Aircraft At Risk for Wing Separation

A Special Airworthiness Information Bulletin has been published for the Seamax Model M-22, an amphibious LSA.

A notable Seamax M-22 incident last year has resulted in a bulletin regarding the integrity of the strut mounting joints on folding-wing aircraft. The October 2022 crash saw the pilot fatally injured during a routine personal flight. In recovering the remains of the aircraft, the NTSB discovered the "right wing was separated from the main wreckage and located in a tree, and the right wing strut was separated from the right wing." More worrisome was their finding that the "bolt attaching the right strut to the right wing remained attached...and was not fractured; however, the nut was not present." The fact that the bolt's threading exhibited "no significant damage" only worsened the impression that the strut/wing attachment point in other Seamax M-22s could be at risk of a disappearing bolt, too. The NTSB notes that the investigation remains ongoing, so definitive causes have not been ironed out. For the time being, the concern is good enough, however, leading the body to advise owners and operators of any possible issues.

They also note that Seamax has previously issued 2 separate Service Bulletins regarding the wing attachment points, both for one-time visual inspections on the fittings and a repetitive inspection to be performed during all preflight checks. Seamax has released a Safety Directive to replace the nuts and bolts of the attachment points of the upper terminal of both wings struts, but the NTSB advises that operators continue with the inspection regimen as per usual.

FMI: www.faa.gov