Operational Considerations Fuel System

There is no full tank protection during a manual centre to inner tank transfer. The centre tank capacity is 33,300 kg and the inner tank capacities are 33,578 kg (SG 0.785), so need to wait until 17,000 kg in each inner before transferring fuel to avoid the risk of overflow.
If both centre tank pumps fail, the transfer is by gravity. In this case, 15,000 kg (in the centre tank) is then unusable. However, still wait until 17,000 kg in inners to avoid fuel flowing back from inners to centre tank during a manual transfer.
Because forward transfers are into the centre tank if it has fuel, some or all of the trim tank fuel may also be unusable if both centre tank pumps have failed.

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