Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, 700C, -800, -900, and - 900ER series airplanes. This proposed AD was prompted by a report of installation of incorrect wire support clamps within the left and right Environmental Control Systems (ECS) bay area during production, which is a flammable leakage zone. Use of incorrect wire support clamps that are not fully cushioned could allow electrical power wiring to come in contact with the exposed metal of the improper clamp, causing a short circuit and subsequent electrical arcing. This proposed AD would require inspecting to identify the part number of the wire support clamp, and related investigative and corrective actions if necessary. We are proposing this AD to prevent electrical arcing and a potential ignition source, which, in combination with flammable fuel vapors, could result in a fuel tank explosion, and consequent loss of the airplane.