Definition
A landing gear component that absorbs and dissipates the impact energy of landing and the shocks of taxiing. Most shock struts are oleo-pneumatic, using a combination of compressed air (or nitrogen) and hydraulic fluid inside a sealed cylinder. On touchdown, the strut compresses; fluid is forced through a small metered orifice, which dissipates energy as heat, while the gas spring cushions the load and returns the strut to its extended position.
Plain English
The part of the landing gear that soaks up the bump when the airplane lands or rolls over rough ground. It works like a heavy-duty shock absorber filled with oil and pressurized gas.
Context Anchor
Seen during preflight inspection of the landing gear and in discussions of landing loads, taxiing, and aircraft servicing.
Derivation
"Shock" refers to the sudden impact force at touchdown. "Strut" comes from an old word meaning a rigid supporting piece. Together: a supporting leg designed to handle shock loads.
Why Pilots Care
It protects the airframe from damage and maintains directional control on the ground by converting landing energy into controlled fluid and gas movement.
Analogy
It works like the shock absorber on a car, but built for aircraft landing loads. When the airplane settles onto the runway, the strut compresses to soften the hit instead of letting the full force go straight into the airframe.
Intuition Check
Do not think of a shock strut as just a rigid metal support. In aircraft landing gear, it is meant to compress and cushion the force of landing and taxiing.
Example Sentence 1
During preflight, the pilot checked that each shock strut was extended the correct amount, indicating proper gas pressure.
Example Sentence 2
During the inspection the mechanic checked the shock strut for proper fluid level and nitrogen pressure.