The Department of Transportation’s Federal Aviation Administration (FAA), aimed in part at regulating civil aviation and US commercial space transportation, recently adopting a new airworthiness directive (AD) for a number of Boeing airplanes, requiring the inspection of motor-operated valve (MOV) actuators. The AD encompasses all Boeing Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, Model 757 airplanes, Model 767 airplanes and Model 777 airplanes.
This AD results from fuel system reviews conducted by the manufacturer. This AD requires an inspection to determine if certain MOV actuators for the fuel valves are installed, as well as the replacement of any affected actuators. Previous ADs addressed th Special Federal Aviation Regulation No. 88 (SFAR 88) issue for the majority of the airplanes delivered with these actuators. Since those ADs did not cover all of the airplanes – and for some airplanes delivered with improved actuators, there was no restriction on installation of replacement actuators with the unsafe condition – this additional rulemaking action is required. As with the related ADs, the FAA is issuing this AD to prevent electrical energy from lightning, hot shorts or fault current from entering the fuel tank through the fuel valve actuator shaft, which could result in fuel tank explosions and consequent loss of the airplane.