PART I-DESCRIPTIVE
(b) Three switches control the booster pumps. They arc the
FUEL MASTER ON/OFF switch (31), the two-position
TAKE-OFF-NORMAL auto override switch (36) and
the three-position AUTO-RETRIM switch (at 61).
Circuit breakers and test switches are in the starboard
side of the equipment bay. Below generator cut-in speed
the wing and rear tanks booster pumps do not switch on.
(c) At all times when the engine is running, the fuel master
switch should be ON and, unless manual fuel balancing
is necessary, the balance switch should be at AUTO.
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A.L.3 (d) When the belly tank is carried and the override switch is
Para 4(d) set to TAKE-0FF, the internal booster pumps operate in
Page 11 the normal manner but the belly tank booster pump is
inoperative. When the switch is set to NORMAL, if the
belly tank contains fuel and the fuel is transferring cor-
rectly, only the belly tank booster pump remains in
operation. The other booster pumps are inoperative until
either a pressure switch (transfer rate below minimum)
or a float switch (tank empty) operates to switch off the
belly tank pump and to switch on the internal tanks
pumps. Automatic balancing then commences.
NOTE-When reheat is in use below 15,000 ft., all
pumps are in operation irrespective of the switch
setting. Above 15,000 ft. with the switch at
NORMAL, belly tank fuel is used first, and then
auto balancing commences.
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(e) (i) When automatic fuel balancing is in operation. the
fuel in the front and centre tank group is kept in
balance with that of the rear and wing tank group,
in order to keep the C.G. within reasonable limits.
To achieve this balancing, a relay, working with the
fuel contents amplifiers, varies the speed of
operation, and thus the output, of the booster pumps.
(ii) Two magnetic indicators (at 61) are alongside the
AUTO-RETRIM switch, and provide nose- or tail-
heavy indications. The appropriate indicator shows
white when such a state occurs and remains so until
correct balance is again achieved. 11
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