PART IV-EMERGENCY HANDLING
lb. sq. in. Harsh movements of the power controls or
use of airbrakes will then deplete the hydraulic accumu-
lators and lead to Manual reversion. It is therefore
recommended that if the emergency button is going to be
used under these conditions power controls be selected
to Manual first.
(c) To raise the undercarriage after use of the emergency
system, reselect the emergency button and select UP on the
normal system. If hydraulic pressure is available, the
undercarriage should retract.
(d) If it is necessary to retract the undercarriage whilst the
aircraft is on the ground, rotate the UP selector button
clockwise and press.
NOTE:-1. This must not be used to retract the under-
carriage in the air if it is found that the UP
button cannot he pressed in. In this case the
wheels must he left down and the aircraft
landed.
2. If the undercarriage has not been lowered by
normal selection the air extractor valve will
not be in the correct position. The engine
should he shut down at the end of the landing
run to prevent overheating.
87. Wheel brakes emergency operation
(a) The wheel brakes accumulator provides sufficient
pressure for brake operation during landing down to a
pressure Of 1,750 lb./sq. in. approximately.
(b) If full brake is applied, the maxaret units will deplete the
accumulators sooner than necessary. It is therefore
recommended that a visual check of the brake gauge is
kept and a steady application of approximately 600
lb./sq. in. is made. The amount of pressure remaining is
shown by the top needle of the triple pressure gauge.
Brakes will fail completely at approximately 1,750
lb/sq. in.
88. Flapless landing
A normal circuit and approach should he made and the
threshold crossed at a speed 5 to 10 knots in excess of the
normal final approach speed. 77
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