PART 1II-HANDLING
aggravated if the balance cock is open. Under these
conditions, if the fuel is low, the fuel outlet of
the uppermost tank may be uncovered, causing failure
of the engine feeding from it. Normally, the balance
cock should be closed.
(ii) When flying on one engine. If a choice is possible, the
starboard engine should be used when flying on one
engine to conserve fuel, for the following reasons.
1. In level flight at range speed, the main fuel tank is
in a slightly nose-up attitude; therefore, with the
balance cock open, fuel will flow into the
rear compartment, from which the starboard en-
gine is supplied.
2. The hydraulic pump is driven by the starboard
engine.
The following table gives a guide to the use of the
balance cock during single-engined flying:-
| Condition of flight |
Engine in use |
Position of balance cock |
| Climb |
Port
Starboard |
Closed
Open |
| Descent |
Port
Starboard |
Open
Closed |
| Level |
Port
Starboard |
Closed only if I.A.S.
below approx. 250 knots
Open |
NOTE.-With the live engine at or near full power,
its fuel demand will normally be greater than
the flow through the balance cock. Because
of this, unless the fuel exceeds 35 gallons in
the compartment not directly feeding the
engine, it is possible to empty the other
compartment.
(e) Booster pump failure
Should an L.P. pump fail during flight it will be impossible
to obtain maximum r.p.m. at high altitudes, or at high
speed at low altitudes, on the engine concerned. In addi-
tion, the engines may flame out due to fuel starvation. The34
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