Definition
The principal load-bearing wheels of an airplane's landing gear, located near the aircraft's center of gravity, which carry most of the airplane's weight on the ground and absorb the primary impact during landing.
Plain English
The two main wheels of the airplane — the ones under the wings or fuselage that hold most of the weight and touch down first or with the nose/tail wheel during a normal landing.
Context Anchor
You see this term in landing and touchdown discussions, especially when learning which wheels should contact the runway first.
Derivation
“Gear” originally means equipment or apparatus. In aviation, landing gear means the equipment used to support the airplane on the ground. “Main” points to the primary part of that equipment—the wheels and supports that carry most of the load.
Why Pilots Care
Correct main gear contact keeps the nose gear from taking excessive load and prevents bouncing or loss of directional control.
Grounding Statement
During a normal landing, the airplane should settle onto the main gear first, then the nosewheel comes down under control.
Intuition Check
“Main gear” does not mean every part of the landing gear. It means the primary load-carrying wheels and supports, separate from the nose gear or tailwheel.
Example Sentence 1
In a normal landing, the pilot holds the nose off so the main gear touches down first.
Example Sentence 2
After the main gear touched down, the pilot lowered the nose wheel smoothly.