Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 Series Airplanes; and Model DC-9-81 (MD-81) and DC-9-82 (MD-82) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes; and Model DC-9-81 (MD-81) and DC-9-82 (MD-82) airplanes. This AD requires repetitive detailed inspections of the upper and lower caps of the rear spar of the left and right wings, and corrective action if necessary. This AD also provides an optional modification that would end the repetitive inspections. This AD is prompted by reports of fatigue cracks in the upper and lower caps of the wing spar. We are issuing this AD to detect and correct fatigue cracking in the upper and lower caps of the rear spar of the left and right wings, which could result in structural failure of the wings.