Fuel pump is not working normally
Anti return valve in fuel pump is blocked / Return line is blocked
NOTE: As described in the installation manual, the return line must not be shut off even with a ‘fuel off tap’ (such as a
duplex fuel tap) to allow the fuel rail to breathe. After a flight , the engine is hot but fresh fuel is in the fuel circuit. After
shutting down the engine, the heat from the engine warms up the fuel inside the lines.
If the return line has been shut off, fuel cannot “escape” resulting in pressures of up to 30 bar. Such high pressure pushes
the rubber anti-return valve in the fuel pump and can ‘jam’ or ‘block’ the system. On the next engine run, the fuel pump
may not be able to unblock this condition. Consequently, the pump makes a strange noise and there is little or no fuel
pressure in the fuel lines.
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make you sure the fuel return line cannot be shut off.
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Rectify your installation
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Change the fuel pump
Fuel supply is restricted
Check that there is a supply of fuel to the pump (fuel tap/fuel lines,etc)
Check filters
Electrical connections:
Check that the FPCR (Fuel Pump Control Relay) is working (replace if necessary)
Check electrical installation including switch function
