Bombardier says one-third of its 147 Global XRS and Global 5000 super-large business jets have been given a clean bill of health following an emergency airworthiness directive (AD) issued by Transport Canada on 9 October. The mandate came after mechanics working on an aircraft discovered a seized bearing and fractured bolt in the mechanism that connects the elevator power control unit (PCU) to the elevator.
Additional inspections revealed two additional seized bearings on different aircraft, but no fractured bolts. Each side of the independently actuated elevator panels is driven by two PCUs connected to the panels via a pushrod and bearing/bushing/bracket assembly, with two bolts securing the elements together. Failure of the four bolts on either side of the T-tail elevator “could result in disconnection of the elevator control surface which would lead to flutter and loss of the aircraft,” Transport Canada said in the AD.
The full story read at Flightglobal.com