Specifications

SECTION II
MODEL 560 AIRPLANE AND SYSTEMS
LANDING GEAR AND BRAKES
GENERAL
The landing gear is electrically controlled and hydraulically actuated. Each main landing gear
assembly uses a single wheel assembly and an air over oil strut. The two main gear are articulated with a
trailing link arrangement which improves the smoothness of landings. The nose gear has a straight oil over
air strut and a chined tire for water and slush deflection. The main landing gear doors are mechanically
connected to the main gear struts and extend and retract with the individual gear assemblies. The nose
gear utilizes three doors. The rear door is mechanically connected to the nose gear strut and extends aft,
or retracts forward with the nose gear assembly. The two forward double-action doors are mechanically
linked to the nose gear. These doors close with the nose gear fully extended or retracted.
The gear actuators incorporate an internal lock to hold the gear in the extended position. They are
held retracted by mechanical uplocks that are normally released hydraulically. The landing gear completes
a retraction or extension cycle in less than 6 seconds. The gear can be extended at airspeeds up to 250
KIAS (V
LO
extend). It can be retracted at speeds up to 200 KIAS (V
LO
retract). With the landing gear
extended, the maximum speed is 250 KIAS (V
LE
).
CONTROL
The landing gear control panel contains the landing gear handle, an audible warning system, horn
silence switch, three gear safe indicators and a red unlocked indicator. The landing gear handle has two
positions: full down and full up. The gear handle must be pulled out to clear a detent before it can be
repositioned. Operation of the gear and doors will not begin until the handle has been positioned in one of
the two detents. A gear handle locking solenoid, activated by the left main gear squat switch, physically
prevents inadvertent movement of the gear handle while on the ground.
EXTENSION AND RETRACTION
In a landing gear retraction cycle, the following takes place:
1. With weight off the left landing gear squat switch, power is applied to the solenoid lock, allowing
the landing gear handle to be placed in the UP position.
2. Actuation of the gear handle to the UP position:
a. Lights the GEAR UNLOCK warning light when any gear unlocks.
b. Closes the bypass valve to the hydraulic return line, pressurizing the system as required.
c. Positions the landing gear control valve to route hydraulic fluid to the retract side of the
hydraulic cylinders.
3. The landing gear are mechanically latched and held in place by the uplock hooks.
4. Actuation of the three gear up microswitches:
a. When all three indicate the gear is up and locked, they open the bypass valve in the
hydraulic system returning it to open center operation and low pressure.
b. Remove power from the landing gear control valve.
c. Extinguish GEAR UNLOCK indicator light.
The sequence during a gear extension is identical with the following exceptions:
1. Solenoid lock on landing gear handle is not in use.
2. Movement of the gear handle to the DOWN position causes fluid to be routed by the control
valve through the uplock actuators to retract the uplock hooks, releasing the landing gear, and
then to the extend side of the hydraulic cylinders. The green LH, RH and NOSE gear indicating
lights illuminate as each gear locks down. After all gear are down-and-locked, the gear down
microswitches return the hydraulic system to open center operation and essentially trap fluid in
the gear extend system.
I 56OMB-01 Configuration AA 2-23