PART I-DESCRIPTIVE
(c) Hydraulic power reserve
Two accumulators are fitted in the power controls circuits
to provide a reserve of power if the main supply fails.
This reserve may be sufficient for several cycles of aileron
and elevator movement before the controls revert auto-
matically to Manual. Even if no control movement is
made, accumulator pressure will not be maintained for
a long period due to seepage through the hydraulic
components. Certain hydraulic pipe failures can cause
immediate reversion to Manual.
19. Controls and indicators
(a) Ailerons
Hydraulic pressure to the aileron hydroboosters is
selected by pushing in the AILeron POWER on/off
selector (34) below the port side of the instrument panel.
It is pulled out to select Power off.
(b) Elevator
A similar control (64) ELevator POWER on/off is fitted
below the starboard side of the instrument panel for
hydraulic selection to the elevator hydrobooster.
(c) Power controls engagement warning
(i) Two green lights (35) and (62) on the instrument
panel near their respective selectors come on when
their associated boosters are correctly engaged in
Power.
(ii) A red warning light (52) in the centre of the instru-
ment panel flashes if any one of the boosters is not
correctly engaged in Power, once power has been
selected.
(d) Hydraulic failure warning
An audio warning over the pilot's headset, providing the
R/T is on, provides indication that the hydraulic system
is losing pressure. It sounds when pump delivery has
fallen to below 2,150 lb./sq. in.
20. Engaging power controls
(a) When Power is initially engaged on the ground it is
possible that the locking pawls will not be opposite their 28
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