AD FAA-2009-1023

The FAA is revising an existing airworthiness directive (AD), which applies to certain 328 Support Services GmbH Dornier Model 328- 300 airplanes. That AD currently requires modifying the electrical wiring of the fuel pumps; installing insulation at the flow control and shut-off valves, and other components of the environmental control system; installing markings at fuel wiring harnesses; replacing the wiring harness of the auxiliary fuel system with a new wiring harness; and installing insulated couplings in the fuel system; as applicable. That AD also currently requires revising the Airworthiness Limitations section of the Instructions for Continued Airworthiness to incorporate new inspections of the fuel tank system. This AD clarifies the intended effect of the AD on spare and on-airplane fuel tank system components. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to reduce the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.