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AP101B-7200-15
Fuel System
Pre-Start and Starting Checks
21. Prior to start the Flight Engineer selects both tank cocks to INNER
ON. Booster pumps are not normally required for starting, however, if
fuel starvation is suspected (engine fires and runs on priming/accelerator
pump fuel alone) a booster pump can be switched on to ensure that the
main fuel lines are fully primed. The fuel pressure indicators are to be
monitored during start and should extinguish as the engine picks up.
After Starting Checks
22.
Positive Flow Checks.
To prove a positive flow is available from
both main tanks booster pumps with ON or OFF selected the following
actions are to be completed:
a. When the engines are started they are run for at least 45 seconds
from the INNER tanks, booster pumps OFF, followed by 45 seconds
on the OUTER tanks, booster pumps OFF.
b. Both INNER and OUTER booster pumps are then switched ON
and the engines run for 45 seconds from the OUTER tanks followed
by 45 seconds on the INNER tanks.
Fuel Usage
23. The main tank booster pumps must be ON for take off, landing and
all flight below 1,000ft. In order to preserve pump life pumps may be
switched OFF for transits above 1,000ft but, in the event of engine failure,
they must be switched back ON immediately to avoid air being drawn
into the adjacent engine.
24. To aid wing relief, fuel should be kept outboard for as long as possible.
Accordingly, the INNER tanks should be used until their contents reach
70 gallons; the fuel feed is then taken from the OUTER tanks. The
RESERVE tank fuel is transferred into the OUTER tanks once the total
fuel in the main tanks approaches that required for safe flight ie 280
gallons plus task fuel. The RESERVE tanks fuel should be transferred
in stages commensurate with fuel usage but the tanks should always
be empty for landing to reduce wing flexing. The only exception to this
is if excess fuel has been carried because of unavailability of AVGAS at
the destination airfield when it is better to land with fuel in the RESERVE
tanks than take off with them empty.
UNCONTROLLED DOCUMENT - NOT FOR USE IN FLIGHT OR TO BE PRINTED
UNCONTROLLED DOCUMENT - NOT FOR USE IN FLIGHT OR TO BE PRINTED