PART I-DESCRIPTIVE
26. Wheel brakes
(i) The brakes are operated by the toe action on the rudder
pedals. Brake pressure is supplied from the brake master
cylinders, supplemented by pressure from the hydraulic
system. In the event of failure of the hydraulic system
the brakes function through conventional action of the
brakes master cylinders when toe pressure is applied to
the pedals.
(ii) A parking brake handle (5) is located on the left side
of the instrument panel outboard of the undercarriage
control. The brakes are set for parking by pressing the
toe pedals and then pulling the handle fully out before
releasing the toe pedals. The brakes may be released by
either pushing the toe pedals or pushing the brake handle
fully in.
27. Instruments
(i) Airspeed indicator
The airspeed indicator (10) has a red and yellow striped
needle which moves to indicate the airspeed correspond-
ing to the limited Mach number at the existing altitude;
clockwise movement of the pointer is limited by a
stop which is pre-set at the maximum I.A.S. limitation.
When the I.A.S. needle coincides with the striped needle
the aircraft is moving at the maximum permitted I.A.S.
or the critical Mach number whichever is less. On some
aircraft a mark on the A.S.I. at 185 knots indicates the
max. airspeed for lowering flaps or undercarriage.
(ii) Accelerometer
An accelerometer (9) indicates all positive and negative
G loads. Three pointers are fitted, one indicating the
maximum positive G load imposed during a given period,
the second giving the maximum negative G load imposed
whilst the third gives the instantaneous loading on the
aircraft. The instrument may be reset by pushing the
small knob on the case.
(iii) Artificial horizon
The artificial horizon (21) has an OFF indicator flag
which appears at the top right of the instrument when
the gyro is not up to speed or when power is not
supplied. It also has a caging knob to permit quick erec-
tion after toppling. The caging knob should be pulled
out slowly to avoid damaging the instrument. If the
artificial horizon is erected in any attitude other than
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