Airworthiness Directives; Boeing Model 737 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 737 series airplanes, that requires revising the FAA-approved maintenance program to prohibit the use of pressure washing within the wheel well or on the landing gear and to prohibit the use of pumps and/or nozzles for washing wheel wells or the landing gear; or incorporation of a certain Temporary Revision to the Boeing Airplane Maintenance Manual into the FAA-approved maintenance program. This amendment is prompted by a review of the design of the flight control systems on Model 737 series airplanes. The actions specified by this AD are intended to prevent corrosion of certain equipment due to the use of inappropriate pressure washing techniques. Corrosion of bearings, cables, electrical connectors, or other equipment in the main wheel well, if not detected and corrected in a timely manner, could result in reduced controllability of the airplane.