4 - Landing gear Flashcards
What is the purpose of the Pivot Trunnion?
Anchor the undercarriage to the aircraft structure
What is the purpose of the Trunnion Beam?
Allows undercarriage to pivot as it is extended and retracted
What is the purpose of the Drag Brace?
Braces the gear in fore and aft axis, one in front and one on aft side of main strut
What is the purpose of the Torque Arms?
Maintain the fore-aft alignment of the bogie
What is the purpose of the Upper and Lower Side Braces? How does it retract?
Supports the gear laterally, has hinge pin that allows gear to extent/retract
What is the purpose of the pivot fork and shaft?
Pivots the pivot beam to the main strut
What is the purpose of the pivot beam “H” member?
Has wheels and axles attached
What is the purpose of the equaliser?
Limits the tilt position of the bogie/pivot beam so the wheels spin up to the ground nicely
What is the purpose of the positioner/trim actuator?
Hydraulic ram which angles the bogie/pivot beam into the position set by the equaliser
What system is in place to maintain the alignment of the nose wheel before retraction?
Lower and upper locating/centering cams, when the strut is compressed the cams do not align so the nose wheel can be used for steering
Explain the operation of a nose wheel steering system?
Steering tiller in cockpit is turned by pilot, its position is transmitted (via electric servos or digital data system) to a hydraulic metering valve. The metering valve ports hydraulic fluid to actuators moving the nose wheel, when the desired angle is reached a follow up system returns the metering valve to a neutral position.
What are the safety systems implemented to prevent inadvertent retraction? (3)
Mechanical down locks
WOW/Squat switch
Ground lock pin
How do boosted brakes operate?
Same principle as independent brakes but when brake pressure is applied a spring loaded toggle moves a spool valve in the cylinder, hydraulic pressure can then flow to the piston, increasing braking pressure
How do power brakes operate?
