Summary
We propose to supersede Airworthiness Directive (AD) 2014-03- 14, for all Airbus Model A330-200 and -300 series airplanes, and Model A340-200, -300, -500, and -600 series airplanes. AD 2014-03-14 currently requires removing bulb-type maintenance lights; installing a drain mast on certain airplanes; and installing muffs on connecting bleed elements on certain airplanes. Since we issued AD 2014-03-14, we have determined that additional actions are necessary to address the identified unsafe condition for certain airplanes on which muffs are installed. For certain Model A340-200 and -300 series airplanes, this proposed AD would also require replacing certain insulation sleeves with new insulation sleeves. We are proposing this AD to prevent ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.