Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposed AD was prompted by reports of chaffing, arcing, and burning damage to the control cabin overhead wiring and ducting with smoke and fire caused by metal clamps installed on certain hoses. This proposed AD would require inspecting for the presence of metal clamps, replacing metal clamps installed on the hoses to the air conditioning temperature sensor, gasper air outlet, and diffuser on the left side of the control cabin with plastic tie straps, and inspecting for and repairing damaged wire bundles. We are proposing this AD to prevent damage to wire bundles, which could cause electrical arcing that could result in a fire or smoke in the control cabin of the airplane.