METRO 23 Servicing Fuel System Safety Precautions ... - NATA

valve, allow the desired amount of fuel to drain then release the valve. The valves are springloaded to the closed position.Defueling Aircraft1. Position aircraft at least 50 feet from any potential source of ignition.2. Static ground the aircraft using the grounding jacks (some aircraft) in the nose wheel well.3. Static ground the defueling equipment to ground and to the aircraft. The built-in groundingjacks (some aircraft) under the wings may be used for this purpose.4. Open the crossflow valve to drain both wing tanks. With the crossflow valve closed, only theright hand tank will drain. The crossflow valve is operated from the cockpit by turning on abattery switch (See Figure 40) and pressing the crossflow switch in the center of instrumentpanel. The crossflow switch/annunciator will illuminate displaying the words "X FLOWOPEN". Allow approximately three seconds for the valve to open fully, then turn off batterypower before continuing with step 5.5. Remove the access panel located at the center section just forward of the aft spar. Locate thefuel drain fitting with the dust cover (red nipple) attached. (See Figure 8)6. Remove the dust cover by depressing the end cap and pulling straight out.7. Remove the fuel filler caps.8. Install the fuel drain tube assembly (P/N 27-64043-001) or comparable drain hose assemblyby pressing straight on. Fuel will begin to flow when tube is connected.9. Defuel as required.10. When defueling operation is complete, install fuel filler caps and, using battery power, closethe crossflow valve. When the crossflow valve is fully closed, the crossflowswitch/annunciator light will extinguish. Turn off battery power.11. Disconnect the drain hose assembly and replace the dust cover by pressing straight on.12. Install the access panel.NOTE: Residual fuel may be drained at two sump drains located in each wing tank lower skinbetween nacelle and center section, and one on each nacelle outboard side, under the wing at themain spar.