Airworthiness Directives; Twin Commander Aircraft Corporation Models 690, 690A, and 690B Airplanes

We are adopting a new airworthiness directive (AD) for all Twin Commander Aircraft Corporation (Twin Commander) Models 690, 690A, and 690B airplanes. This AD requires 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 AD requires you to reinforce the support structures for the inboard and center aileron hinge fittings on both wings. This 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 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.