Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This proposed AD would require repetitive detailed inspections for cracking of the left side and right side frame and reinforcement angles at fuselage station (FS) 640 between stringer 9 and stringer 12, and corrective actions if necessary. This proposed AD results from reports that cracks have been discovered on the frame and reinforcement angles at FS 640. We are proposing this AD to detect and correct cracking of the frame, which could lead to failure of the fuselage structure and possible loss of the airplane.