All operators of certain Bombardier Challenger 600-series aircraft with General Electric CF34-3A1/-3B/-3B1 turbofans will soon receive word in the form of an emergency airworthiness directive 2007-04-51 informing them that an electrical arc-out defect potentially introduced during manufacturing could lead to uncontained engine failure. The FAA found that the defect can be introduced during the part-marking phase of manufacturing. This emergency AD results from the investigation of a fan disk failure episode aboard a Canadair Regional Jet that resulted in in-flight departure of the fan, forward cowling and fan reverser. Operators must comply within 20 engine flight hours of receipt of this emergency AD, specifically performing visual and tactile inspections on 31 fan disks listed in the AD that have not had a shop-level inspection.
