Owners, operators and pilots of Cessna 177 and 210 models need to know about a recent airworthiness bulletin for inspections of wing carry through spars. The alert covers all Cessna 177 models and Cessna 210 models with cantilevered wings, that have no bracing struts.
AWB 53-011 Issue 1 is in response to a fatal accident involving an Australian registered Cessna T210M near Mount Isa, Queensland, in May. The crash was the result of a fatigue fracture of the carry-through spar, after cracking had grown from a corrosion pit on the lower surface of the spar. The spar failed inboard of the right-hand wing attachment lugs.
An accident investigation by the Australian Transport Safety Bureau is underway and a preliminary report shows that the spar had experienced very minor surface corrosion pitting, with no other mechanical damage found at the fracture surface. A review of defect reports and industry feedback regarding corrosion to carry-through spars fitted to Cessna 210 G through M models show that the design is prone to moisture ingress at the upper wing skin joint.
Cessna advises all models of the 177 have the same design and potential for similar corrosion on the carry-through structure. Both early and later Cessna 210 and 177 models can also experience moisture ingress from the wing root rib panel cut-outs located near the wing attachment lugs on the carry-through spar. In the bulletin, CASA makes six recommendations for inspections of Cessna 177 and 210 aircraft, based on current available information. The recommendations apply to around 330 Australian registered aircraft.