Configurations and arraignments
This common three-wheel landing gear configuration uses a nose wheel and two main wheels, allowing for forceful braking without nosing over.
What is the tricycle-type landing gear?
These self-contained hydraulic units convert vertical shock energy from landings into heat using compressed air or nitrogen mixed with hydraulic fluid.
What are shock struts?
On an aircraft cockpit landing gear indicator panel, this color typically illuminates to notify the flight crew that the gear is "down and locked".
What is green?
Modern aircraft wheels are split into two halves—inboard and outboard—primarily to assist a technician with this task.
What is mounting a tire?
This cockpit control device, typically mounted on the captain’s left-hand side wall, is used to steer the nose wheel on large aircraft during taxiing.
What is a tiller (or steering wheel/joystick)?
This specialized type of landing gear is installed on aircraft to allow safe landings and operations specifically in snowy areas.
What are skis?
This specific component prevents the lower strut cylinder from rotating relative to the upper cylinder to keep the wheels properly aligned.
What are torque links (or torque arms)?
These electrical safety switches prevent accidental gear retraction while the aircraft is resting on the runway by detecting main strut compression.
What are squat switches?
These safety devices built into the inboard wheel half melt at extreme temperatures to deflate the tire safely and prevent a catastrophic wheel explosion.
What are thermal plugs (or fusible plugs)?
This specialized unit controls and dampens rapid nose wheel oscillations during ground movement using hydraulic or surface-effect restriction.
What is a shimmy damper?
Aligned strictly along the aircraft's longitudinal axis, this rare gear setup is primarily utilized by sailplanes and select military bombers like the B-52.
What is tandem landing gear?
These key structural components support the aircraft's weight when the gear is down and allow the gear assembly to pivot smoothly during retraction.
What are trunnions?
This alternative safety feature uses a non-contact, two-piece configuration to monitor gear position, door status, and weight-on-wheels (WOW).
What are proximity sensors?
This critical safety step must always be performed before removing a wheel assembly from an aircraft to completely avoid explosive structural failure.
What is deflating the tire?
This value represents the difference between the forward ground speed of the aircraft and the actual rotational speed of its tires.
What is the slip ratio?
This classification of landing gear remains completely exposed to the slipstream during flight and is most commonly found on small, slow aircraft.
What is fixed landing gear?
This type of non-shock absorbing landing gear system handles impact forces using flexible materials like spring steel or aluminum and is popular on single-engine Cessnas.
What is leaf-type spring gear?
This test procedure, also colloquially known as "swinging the gear," requires placing the aircraft on jacks to verify extension, retraction, and emergency systems.
What is a landing gear retraction test?
This specific type of bearing defect occurs when repeated operational stress leads to metal fatigue, causing small pieces of metal to break away and leave pits.
What is spalling?
These fast-acting hydraulic components respond to electronic commands from the anti-skid control unit to rapidly dump or supply pressure to individual brake assemblies.
What are anti-skid control valves?
In a conventional tail wheel-type landing gear configuration, this structural assembly is positioned forward of this critical reference point.
What is the center of gravity?
This solid, rigid structural beam is designed to secure the landing gear and specifically prevent it from folding backward or forward upon landing impact.
What is a drag strut?
In large hydraulic retraction systems, these specialized valves ensure proper timing so that the gear doors fully open before the gear itself moves.
What are sequence valves?
This form of bearing damage happens under heavy load or shock (like a hard landing) when the rolling elements physically dent the race.
What is brinelling?
This specific sub-circuit within the anti-skid system blocks brake pressure from building during flight and touchdown until the squat switch detects full ground contact.
What is touchdown protection?