Airworthiness Directives; Boeing Model 707 Airplanes, and Model 720 and 720B Series Airplanes

We are adopting a new airworthiness directive (AD) for certain Boeing Model 707 airplanes, and Model 720 and 720B series airplanes. This AD requires repetitive detailed inspections to detect cracks and corrosion on any existing repairs and at certain body stations of the visible surfaces of the wing to body terminal fittings including the web, flanges, and ribs; and applicable related investigative and corrective actions. This AD results from reports of cracks found in the wing to body terminal fittings during routine inspections. We are issuing this AD to prevent cracks and corrosion in the body terminal fittings, which could cause loss of support for the wing and could adversely affect the structural integrity of the airplane.