PART I-DESCRIPTIVE
(iii) The total usable fuel in each tank is as follows:-
Imp. galls
Forward fuselage tank and centre-section
tank ... ... ... ... ... 162
Aft fuselage tank ... ... ... 88
Two wing tanks (56 galls. each) ... 112
Total internal capacity: 362
Total capacity with 2 x 100 gall. drop
tanks ... ... ... ... 562
Total capacity with 2 x 167 gall. drop
tanks ... ... ... ... 696
362 Imp. gallons = 2787 lb. AVTAG fuel (spec
gravity .77)
562 Imp. gallons = 4327 lb. AVTAG fuel (spec
gravity .77)
696 Imp. gallons = 5359 lb. AVTAG fuel (spec
gravity .77)
2. Fuel system description
(i) Fuel is fed from the centre-section tank through an L.P.
cock to the engine-driven (H.P.) fuel pump and then past
the H.P. cock to the engine burners. A fuel flow regulator
provided with a governor, and a fuel control valve are
linked to the throttle valve to ensure that the r.p.m.
selected by the throttle setting are maintained regardless of
altitude or airspeed changes. The governor helps to main-
tain constant r.p.m. for a given throttle setting,
but idling r.p.m. increase with altitude causing the first
portion of throttle travel to be less effective at higher
altitudes.
(ii) An emergency fuel pump and regulator are fitted as a
stand-by for the main fuel system. This emergency
system can be turned off, or placed in a test posi-
tion by use of an emergency fuel switch on the cockpit
port wall. The emergency system is controlled in the
same manner as the main fuel system - through
mechanical linkage to the throttle. Compensation is
made for altitude changes, in order to maintain r.p.m.
selected by the throttle setting, but there is no overspeed
protection. The emergency system should be tested
before take-off (see para. 55) and should be put on in
flight only in the event of main system failure. With the
emergency fuel switch ON it is possible for the emer-
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