LANDING GEAR
Description
Aircraft Operations Manual
13.1
PAGE
1
Apr 01/15
1.
GENERAL
The aircraft is equipped with a conventional retract-
able landing gear.
The main gears are located in the engine nacelles
and the nose gear in the forward fuselage. All gears
retract forward.
Each gear is equipped with dual wheels.
Normal landing gear operation is by hydraulic power
but in an emergency the gear can be extended by
free fall or by use of the hydraulic hand pump. In-
dications are provided for gear down and locked
and for any landing gear/gear handle disagreement.
All main wheels have disc brakes. An anti
−
skid sys-
tem automatically modulates the brake pressure for
maximum braking efficiency.
The nose gear is steerable by a wheel located on
the left pilot’s side panel.
A ground sensing system with incorporated weight
on wheel switches (WOW) establishes ground or
flight mode operation for various systems.
An optional removable tail supporting strut that at-
taches to the under side of the rear fuselage is
available. The strut prevents damage to the rear
fuselage of the aircraft if it contacts the ground
should the center of gravity move aft of the main
gear. A stowage for the strut is provided under the
flap of the cargo compartment floor.
2.
MAIN COMPONENTS AND SUBSYSTEMS
2.1
Landing gear extension/retraction (Fig. 2)
All gears retract forward into their respective wheel
wells.
The gears are retained in up or down position by
locks. Manually inserted lock pins ensure downlock-
ing during ground operation. The landing gear doors
are mechanically controlled by each gear. The main
gear doors are partly closed, and the nose wheel
doors are fully open, when the landing gear is ex-
tended.
The gears are extended/retracted in normal mode
and can also be extended in emergency mode.
Normal extension/retraction
With gear UP selected, an electrically operated con-
trol valve ports hydraulic pressure to release the
downlocks and pressurize the hydraulic actuators.
A mechanical lock on the landing gear control han-
dle prevents selection of gear up on ground. In
flight, this lock is disengaged by a solenoid. Should
the solenoid fail, the handle can be released by
pressing the DOWN LOCK REL button to the left of
the gear handle. When the gears are up, an up
−
lock hook will engage a roller on the gears and re-
tain them in the retracted position.
With gear DN selected, hydraulic pressure is ported
to the uplocks and hydraulic actuators. As soon as
the gears are fully extended, the downlocks will en-
gage.
Indicators
The landing gear indicators consist of three green
lights on the gear handle unit and an amber light in
the gear handle knob. The lights are controlled by
the position of the handle and by the downlock and
uplock switches.
Emergency extension
If normal extension of the landing gear is not suc-
cessful the hand pump can be used for extension.
By setting the hand pump selector in center position
(FLAPS LDG GR) and gear handle selected down,
hydraulic pressure is ported to the MAIN HYDR ac-
cumulator which in turn pressurizes the uplocks and
hydraulic actuators.
In case of hydraulic failure, the gear may be ex-
tended by free fall. By pulling the landing gear
emergency extension handle in the cockpit floor, the
gear actuator hydraulic pressure lines will be con-
nected to the return lines to prevent hydraulic lock.
Emergency accumulator pressure will then release
the uplocks and the gear will extend and lock by
gravity and aerodynamic forces. The position of the
landing gear control handle has no effect on an
emergency extension, except that the Amber dis-
agreement light will come on indicating a disagree-
ment between landing gear and gear handle if the
handle is left in up position.
To aid free fall of the main landing gear at an emer-
gency extension the gear door mechanism is dis-