PART IV - EMERGENCY HANDLING
either of the undercarriage selector buttons are in,
all hydraulic fluid will be jettisoned, resulting in
Manual reversion. The rate of jettisoning is greater
if the UP button is in. Therefore depending on
prevailing weather conditions, the following should
be borne in mind.
(iii)If conditions are favourable, i.e., good visibility,
and a steady wind down the runway, Manual should
be selected before operating the emergency control
and the landing made in Manual.
(iv) If conditions are not favourable, i.e., a strong cross
wind or if the wind is gusting, the loss of hydraulic
fluid may be prevented if both undercarriage selector
buttons are set to the out position. To achieve this
carry out the following procedure:-
1. Select up normally to ensure that the 'DOWN'
selector button is out.
2. Pull out the 'UP' button, which requires little
effort, and ensure that it remains out.
3. Operate the emergency air selector by holding
the knob in and then pulling the handle.
WARNING.-It is essential that the UP button remains
out. There is a tendency for it to return to
the in position. If this occurs Manual
reversion will follow, in which case the
power control switches must be set to OFF.
(v) With both selector buttons out, both solenoids in
the selector valve are de-energized enabling the slide
valve to adopt a neutral position. The undercarriage
hydraulic lines are thus isolated from the remainder
of the hydraulic system and only the fluid in the
lower end of the jacks will be jettisoned. The flying
controls will remain in Power and the flaps may be
operated normally. When the undercarriage up
selector button is out the airbrake is isolated.
(vi) If complete electrical failure has occurred, both
solenoids in the selector valve will automatically be
de-energized and the slide valve will be in the
neutral position. When the emergency lowering
system is used only the fluid in the lower end of
the jacks is jettisoned.
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