Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This AD was prompted by reports that elevator power control unit (PCU) shear pins may fail prematurely. This AD requires repetitive replacement of the elevator PCU shear pins. We are issuing this AD to prevent premature elevator PCU shear pin failure. If all pins fail on one elevator, the elevator surface would become inoperative, which could reduce the controllability of the airplane and could result in a loss of redundancy for flutter prevention.