Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-1A11 (CL-600), CL-600-2A12 (CL- 601), CL-600-2B16 (CL-601-3A, CL-601-3R, & CL-604 Variants) airplanes. This proposed AD was prompted by reports of cracking found on the upper and lower web of the engine support beam. This proposed AD would require revising the maintenance program. We are proposing this AD to detect and correct fatigue cracking of the engine support beam, which could result in failure of the engine support beam and affect the structural integrity of the airplane.