Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, that would have required inspection of wire bundles in two junction boxes in the main wheel well to detect chafing or damage, and follow-on actions. This new action revises the proposed rule by expanding the applicability to include additional airplanes and models, and by adding new inspections for chafing or damage of two additional junction boxes in the main wheel well and follow-on actions for those boxes. This action is necessary to prevent wire damage, which could result in arcing and consequent fire in the main wheel well or passenger cabin, or inability to stop the flow of fuel to an engine or to the auxiliary power unit in the event of a fire. This action is intended to address the identified unsafe condition.