Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, - 30, and -40 Series Airplanes; and C-9 (Military) Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, and - 40 series airplanes; and certain C-9 (military) series airplanes. This amendment requires modifying the piping of the potable water system. This amendment is prompted by reports of ice forming on the control cables in the wheel well of the left main landing gear due to the freezing and rupturing of undrained potable water pipes. The actions specified by this AD are intended to prevent such ice formation, which could render the slat, aileron, and spoiler flight controls inoperative, and consequently could result in reduced controllability of the airplane.