##  [Landing Gear](/landing-gear-0) 

 Definition

An aerospace and automotive concept defining a technical component, process, or performance measure used in vehicle design, production, or operation. It applies when relevant engineering prerequisites are satisfied and produces defined effects on safety, efficiency, reliability, or manufacturability. It does not ensure outcomes without validated design assumptions and appropriate testing and controls. It materially affects lifecycle performance and cost by influencing design tradeoffs, verification effort, and operational robustness. The concept is generally stable, though methods and standards evolve as technology advances over time.



 

 

 

 

 

 





## Principle

Principle

Provide load-bearing support and controlled energy absorption during ground operations while permitting aerodynamic retraction and extension to meet flight and ground performance requirements.

 

 

 

 

 





## Demonstration

Demonstration

On a narrow-body transport, the main landing gear extends before touchdown, its oleo struts absorb vertical energy from the landing, wheels and brakes manage deceleration on rollout, and the gear retracts into bays during climb to reduce drag; a hard crosswind landing illustrates coordinated structural, hydraulic and control interactions and shows how shock absorption limits transmitted loads.

 

 

 

 

## Misapplication

Misapplication

Treating landing gear purely as static supports and omitting dynamic energy absorption or retraction considerations; for example, designing struts only for static weight without accounting for vertical landing velocities, which can lead to structural damage or collapse under hard landings.

 

 

 

 

 





## Consequence

Consequence

When designed and maintained correctly, landing gear provides predictable ground handling, survivable load paths to the airframe, controlled deceleration, and minimised structural damage and crew/passenger risk; it also enables operational flexibility through retraction for aerodynamic efficiency.

 

 

 

 

## Reversal

Reversal

A reversed concept would be an aircraft with permanently fixed, non-retractable supports that provide no energy absorption (e.g., rigid skids) or a flotation-only system that trades runway operability for water operations; both invert the gear's balance of retraction and energy management.

 

 

 

 

 





## Boundary

Boundary

Includes primary and auxiliary gear assemblies and their onboard subsystems (struts, wheels, brakes, actuation). Excludes external ground-support equipment not attached as a designed aircraft subsystem (tow tractors, jacks) and excludes emergency arrestor barriers or runway-specific devices unless they are integral to the aircraft's certified landing arrangement.

 

 

 

 

 





## Semantic Tension

Semantic Tension

The term overlaps with 'undercarriage' and with subcomponents (strut, bogie, axle); disputes arise whether 'landing gear' denotes the entire subsystem or only the retractable assemblies, and confusion can occur with unrelated 'gear' usages in other domains.

 

 

 

 

 





## Synthesis

Synthesis

Landing gear is the integrated ground-contact subsystem that combines structural support, controlled energy absorption, and retraction/extension mechanisms to safely transition the aircraft between flight and ground operations while meeting load, performance, and maintainability constraints.