AIRPLANE
OPERATIONS
MANUAL
LANDING GEAR AND
BRAKES
REVISION 38
2-12-05
Page
5
Code
01
AOM-145/1114
LANDING GEAR EXTENSION
NORMAL EXTENSION
Positioning the Landing Gear Lever to the DOWN position signals the
LGEU to command the Landing Gear Electrovalve and the Nose Gear
Doors Solenoid Valve. This allows pressure from the hydraulic system
1 to simultaneously reach the landing gear and door actuators, and
also the up unlock actuators.
When the gear legs reach the down position, the down lock boxes are
actuated. The proximity switches signal the LGEU that the gear is
down and locked and that the Landing Gear Electrovalve may be
de-energized.
ELECTRICAL OVERRIDE EXTENSION
The Electrical Override system is used to extend the landing should
there occur a normal landing gear extension failure. This system
bypasses the LGEU and actuates directly the Landing Gear
Electrovalve and the Nose Gear Doors Solenoid Valve. The control
switch is installed inside the free-fall lever compartment, on the floor,
beside the copilot’s seat. Extension through override is made in steps,
first opening the doors and then extending the gear. When extension
is completed, selecting the override switch to normal position
deenergizes the Landing Gear Electrovalve and depressurizes all
lines. The switch is safeguarded, being in the non-actuated position
whenever the compartment door is closed.
FREE-FALL EXTENSION
Free-Fall extension is available in case of failure of both normal
extension and electrical override extension. Actuation of free-fall
landing gear extension is performed by pulling up the lever installed
inside the free-fall lever compartment, on the floor, beside the copilot’s
seat.
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