PART 1 - DESCRIPTIVE
control (42) on the instrument panel, is pulled, after first
pressing in the central knob, the air is directed to the
lowering jacks. The available pressure is shown on a
gauge(7)at the aft end of the port shelf.
33. Airbrake control
(a) An under-fuselage airbrake is provided, which is
electrically selected and hydraulically operated. It will
extend fully at any speed.
(b) Control of the airbrake is by means of a three-position
switch (29), spring-loaded to the central off position, on
the throttle lever. No position other than fully in or fully
out can be selected. A magnetic indicator (39) on the
instrument panel shows black only when the airbrake is
(c) The airbrake is automatically inoperative when the under-
carriage is lowered. If the undercarriage is lowered when
the airbrake is out, the airbrake will automatically
retract. Airbrake IN must not normally be obtained by
selecting undercarriage down.
(d) A spring-loaded switch (13) on the port wall enables the
airbrake to be tested on the ground. When the switch is
held to TEST the airbrake extends through 10° only and
then retracts with a slight bump. The indicator shows
white momentarily when the airbrake is out.
34. Wheel brakes control
(a) The wheel brakes are operated hydraulically by means of
a lever attached to the forward face of the control column
and a differential relay controlled by the rudder bar.
(b) The live-line pressure (3,000 ± 150 lb./sq.in.) is shown
on a triple pressure gauge (21) together with the pressure
at each main wheel(1,500-1,650 lb./sq.in.).
(c) Should the hydraulic system fail, the pressure in the wheel
brakes accumulator, which if fully charged should
provide sufficient pressure for about 40 operations of the