aviation accident: ROBINSON HELICOPTER R22 BETA near Ellington (2013-01-17)
Probable cause: The separation of the collective push-pull tube and jackshaft assembly, which resulted in the total loss of helicopter control and collision with terrain. Contributing to the accident was the inadequate supervision of maintenance personnel by the operator during overhaul, which resulted in inadequate tightening force applied to the collective jackshaft attachment hardware, and the failure of maintenance personnel to detect the loose hardware during subsequent inspections.