Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Twin Commander Aircraft Corporation (Twin Commander) Models 690, 690A, and 690B airplanes. This proposed AD would require you to inspect, visually and using fluorescent dye penetrant, the support structures for the inboard and center aileron hinge fittings on both wings for cracks and replace any cracked support structure. This proposed AD would require you to reinforce the support structures for the inboard and center aileron hinge fittings on both wings. This proposed AD results from reports that cracks were found in the support structures for the inboard and center aileron hinge fittings on both wings. We are issuing this proposed AD to detect and correct cracks in the support structures for the inboard and center aileron hinge fittings on both wings, which could result in aileron failure. This failure could lead to reduced controllability or loss of control of the airplane.