Landing Gear Description

Landing Gear Controls

Main Gear

The main landing gear retracts forward into bulges on the sides of the fuselage to avoid intruding into the cabin area. The main gear consists of the wheel tire, brake, axle, leg assembly, shock strut, drag strut, and position rod. The main gear aft door is connected mechanically to the oleo strut. The main gear forward door is operated separately during landing gear retraction or extension by means of an independent electric actuator. The oleo strut is a standard air and oil type, consisting of a cylinder and piston. The strut absorbs landing and taxiing shock loads. The drag strut sustains ground loads and also serves as a screwjack for gear retraction. The position rod, connected to the leg assembly and axle, receives horizontal loads from the axle and allows retraction of the wheels into the fuselage by swiveling the axle during gear retraction. The ground safety 'switch is mounted on the left gear leg assembly and prevents the gear from retracting while the airplane is on the ground.The nose landing gear consists of an oleo strut, drag struts, twin wheels, tires and tubes. The oleo strut includes a shimmy damper and centering roller. The straightener is installed at the top of the strut and is guided by a centering roller when the gear is retracted. Each of the two drag struts is provided with a down lock. The screw jack for gear retraction is connected to the drag strut on the right hand side. The shimmy damper connects the trunnion with the cylinder to prevent the nose gear from shimmying while taxiing.

Forward View	Aft View

Nose Gear

The nose gear is equipped strut. A torque link disconnecting mechanism is located between the torque links to provide a greater steering angle for towing.Nose wheel steering is 1imited to 23° 1eft and 22° right. When the torque 1ink is disengaged for towing there is no feedback to the rudder pedals or rudder. Since there is no control lock for the rudder system, the nose wheel provi di ng adequate restrai nt, it is important to ensure that the torque 1ink is not left disconnected when the airplane is parked. The tow bar is attached to the axle extremities.The gear operati ng mechani sm is el ectri cally dri ven for nonnal operati on. There is a hand operated system for emergency extension.Each main gear is raised and lowered by extension or retraction of its drag strut, which in turn is driven by its own gearbox. The gearboxes are con- nected to the electric motor linked to the right box.The nose wheel is operated by a torque tube drive connected to the left main landing gear drive box. The torque tube runs from the wheel well outside the 1eft keel member and passes through the pressure cabin, At the forward end, the torque tube drive is transferred by a chain and sprockets to a gearbox driving a screw jack. The screw jack is attached to the right nose wheel drag strut and retraction is effected by breaking the struts. The sprockets are not guarded.In the event of electric drive failure the landing gear may be lowered manual- ly. This is accomplished by operating a handle stowed in the floor between the pilot's seats; Lifting the handle causes the main gear door locks and clutch to disengage, allowing the doors to swing free. The lever operates the torque tube drive which runs along the keel and about 130 full lever movements are required to lower the gear. Extension is complete when three green indi- cator lights illuminate and the handle cannot be moved.The electric motor speeds are reduced to one sixteenth through two stage spur gears in the main reduction gearbox.A cl utch is provi ded for the preventi on of overload upon the mechani sm and slips when torque exceeds 380 - 560 in-lbs. The torque shaft in this system is connected at several places by means of universal joints on the splines.A backup mechani cal stop protects the mechani sm in the event of torque shaft overtravel due to inertia or limit switch malfunction. The main landing gear drag struts incorporate irreversible screw jacks. Consequently, the main gear is not provided with an uplock or downlock. The main landing gear doors con- sist of forward and aft doors. The aft doors are mechanically connected with the main gear oleo strut and operated by the landing gear. The forward doors are opened before and closed after gear operation by an electric actuator. The forward door mechanism is mechanically connected to the main gear aft door lock mechanism which is unlocked when the forward doors open.

Gear Horn / Silence Mode

The gear horn will trigger under the following conditions:

Either one of the power levers are near the flight idle position
Landing gear not extended and locked

When the gear horn is triggered and sounding, then it may be silenced by pressing the horn cutout button; however, once any of the the conditions above are no longer true, usually by moving the power levers forward or extending the gear, then the conditions to trigger the horn are reset; therefore, if you are regularly cycling the power levers to/from the flight idle position during descents without the gear extended, then the horn will sound repeatedly. You may pull the gear horn circuit breaker if you wish to avoid having the gear horn sound at all.

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