The mainspar is the heavy, continuous beam running lengthwise through an aircraft wing, typically from the fuselage to the wingtip. It supports the primary bending and shear loads generated by lift and the weight of the wings, engines, and fuel. Structural integrity relies entirely on this component, making it a primary focus during airframe inspections for fatigue cracks or corrosion.
Heard on the job
The ultrasonic inspection showed a stress fracture near the wing root on the mainspar, so this aircraft is grounded until further notice.
Also heard as
- main spar