The separation was caused by a fatigue fracture of one of the links attaching the flap to the wing.
From the en.wikipedia.org
The cause of the accident was attributed to the catastrophic failure of the Main Rotor Gearbox as a result of a fatigue fracture of a second stage planet gear in the epicyclic module.
From the en.wikipedia.org
The firm was hired to evaluate the fatigue and fracture characteristics of the bridge, URS said.
From the us.cnn.com
The nano-phase will improve the tenacity of the fracture and the fatigue of the composite.