FUEL DISTRIBUTING – CROSSFEED CONDITION
The pilot can operate the cross-feed valve at any time setting the XFEED
switch to OPEN, or CLOSED or NORMAL.
In normal operation the cross-feed valve is closed (switch set to NORM).
If the XFEED switch is set to NORM the cross-feed valve is automatically
opened as a result of single fuel line pressure drop or booster pump failure.
In this case the remaining booster pump supply fuel to both engines.
When the XFEED valve is open and pressure is restored in the failed supply
line, the transducer installed in the fuel manifold provides indications of the
restored pressure.
When the XFEED valve is open but the pressure in the failed supply line is
not restored, possible fuel leak. Close manually the XFEED valve (SUCTION
MODE). The pilot has to be attentive for sign of fuel leak or engine loss of
power.
When cross feeding, the tank with pump off, NOT supplying the engines, will
have a maximum quantity of unusable fuel of 228 kg. This unusable fuel
quantity value will change to grey to indicate the tank can no longer supply
fuel.
Close X-FEED to restore the availability of up to 228 kg of fuel (fuel level
value returns to green). Engine operation, in suction mode, is assured and
FUEL pressure, on MFD, is invalid displaying amber dashed. Avoid abrupt
aircraft manoeuvres.