Definition
Sideways loads imposed on the landing gear when an airplane moves along the runway in a direction that is not aligned with the way its wheels are pointing, typically during a crosswind takeoff or landing roll when the airplane drifts or is angled relative to its direction of travel.
Plain English
Sideways forces pushing on the wheels and landing gear because the airplane is moving in one direction while the wheels are pointing in another.
Context Anchor
You see this term in crosswind takeoff discussions, especially while the airplane is still on the runway and the pilot is keeping it aligned during the takeoff roll.
Derivation
Stress originally meant pressure, strain, or force placed on something. In aviation, it means a force the airplane structure must carry. Here, side stresses are forces coming from the side rather than straight ahead or straight down.
Why Pilots Care
Uncontrolled side stresses can damage tires, wheels, or landing gear and may cause the airplane to veer off the runway.
Intuition Check
Do not read “stresses” as pilot nervousness here. It means physical forces on the airplane, specifically sideways forces during the ground roll.
Example Sentence 1
During the crosswind takeoff roll, the pilot held aileron into the wind and used rudder to keep the nose straight, preventing side stresses on the landing gear.
Example Sentence 2
Strong gusts increased side stresses on the nosewheel until the airplane lifted off and the wind no longer acted through the tires.