MIDTERMS L1: Landing Gear

Up Line (Hydraulic Line)

• Supplies hydraulic pressure for the gear UP operation

• It actuates the latch cylinder, which positions the latch mechanism to lock the door closed

Latches

hold the gear up or down and/or to hold the gear doors open or closed

Down Line (Hydraulic Line)

• Supplies hydraulic pressure for the gear DOWN operation

• It causes the latch cylinder to move in the opposite direction, which releases the latch hook so the door can open

Latch Cylinder

• Converts hydraulic pressure into mechanical movement

• Receives pressure from either the up or down line. Extends or retracts its piston. Moves the latch linkage. Either engages (locks) or disengages (unlocks) the latch hook

• This is the main actuator of the latch system

Cylinder Latch

• Transfers motion from the cylinder to the latch mechanism

• The movement from the Latch Cylinder is transmitted through this linkage.This motion drives the Sector

Sector

• A rotating linkage plate

• Converts linear motion into rational movement

• Transmits motion from the cylinder.

  Controls hook rotation.

  Synchronizes movement of linkage.

  Think of it as the motion distributor.

Latch Hook

• The actual locking element

• Hooks onto the latch roller

• This is what physically “grabs” the door.

Latch Roller

• Contact surface for the latch hook

• Mounted on the door.

  When the door closes, the roller contacts the hook.

  The hook rotates over it and locks.

  The roller reduces friction and wear.

Forward Latch Mechanism

• Front locking assembly of the door

• Engages the latch hook. Works together with the latch cylinder. Secures the forward section of the gear door. It ensures the door stays tightly closed during flight.

Aft Latch Mechanism

• Rear locking assembly

• secondary locking support

• Maintains door alignment

Uplock Switch

• Provides position indication (electrical feedback)

• Detects whether the latch is locked or unlocked. Sends signal to cockpit indication system

Emergency Release Cable

• Manual backup system

• If hydraulic pressure fails:

  Pilot pulls emergency release.

  Cable mechanically pulls the latch mechanism. Hook disengages

  Door opens by gravity or airflow. Critical for safety redundancy.

Door

Covers landing gear when retracted

Closes

During Gear UP: the door ____

Opens

During Gear DOWN: The door ____

Sector

Cables on the landing gear emergency extension system are connected to the ____ to permit emergency release of the latch rollers.

Uplock switch

An _____ is installed on, and actuated by, each latch to provide a gear up indication in the flight deck.

Required Clearance

1⁄8 ± 3⁄32-inch

loosening its mounting bolts and raising or lowering the latch roller support

If the roller is not within tolerance, it may be adjusted by?

Landing Gear Retraction Test

Swinging the gear is also known as?

Nose Wheel Steering

It is steerable from the flight deck via ____ system. This allows the aircraft to be directed during ground operation

Tiller

• a steering control used by pilots to move the aircraft left or right while taxiing on the ground

• Usually located on the side panel near the captain’s seat

Rudder pedals

Mechanical linkages are connected to the ___

Push-pull tubes

____ are connected to pedal horns on the lower strut cylinder

Strut piston axle and wheel assembly

As the pedals are depressed, the movement is transferred to the ____ and ____ which rotates to the left or right.

Push-pull rod system

Nose wheel steering on a light aircraft often uses a _____ connected to the rudder pedals.

Hydraulic Power

Large aircraft use ____ for nose wheel steering due to their heavy weight and need for precise control.

mechanical, electrical, or hydraulic

The pilot’s input is transmitted through _____ connections to a steering control unit.

Shimmy Damper

• It prevents rapid nose wheel vibration and ensures stable steering during aircraft ground operations

• It absorbs and resists rapid side-to-side movement of the nose wheel, stabilizing the landing gear.

• is used to prevent this vibration by applying hydraulic damping

Shimmy

can cause strong vibrations, reduced steering control, and possible structural damage to the landing gear if not controlled.

▪Piston Type

▪Vane Type

▪Non-Hydraulic Shimmy Damper   

Types of Shimmy Damper

Piston Type

• Prevent nose wheel shimmy vibration by using hydraulic resistance inside a piston cylinder.

• Hydraulic fluid is forced through a small bleed hole

Piston

Inside the damper is a ____ moving within hydraulic fluid.

Vane type

Contains a rotating vane inside a sealed housing filled with hydraulic fluid

Non-Hydraulic Shimmy Damper

• A mechanical device used to reduce nose wheel shimmy without using hydraulic fluid.

• Works using friction, springs, or mechanical resistance to limit rapid oscillations of the nose wheel.

• Commonly found on small or light aircraft where hydraulic systems may not be installed.