AD FAA-2021-0309

The FAA proposes to adopt a new airworthiness directive (AD) for MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. This proposed AD was prompted by reports and a design review indicating that there could be possible corrosion on the main landing gear (MLG) outer cylinder at the interface with the gland nut on the shock strut installation and on the forward and aft trunnion pins in the MLG dressed shock strut assembly. This proposed AD would require detailed inspections for corrosion on the MLG outer cylinder assemblies, certain MLG dressed shock strut assemblies, and the MLG outer cylinder at the gland nut threads, thread relief groove, and chamfer; a detailed inspection for the presence of corrosion-inhibiting compound (CIC) on the MLG forward and aft trunnion pins and grease adapter assemblies; applicable corrective actions; application of primer, paint, and CIC as applicable; re-identification of certain part numbers; and marking of the MOD STATUS field of the nameplate of certain parts. The FAA is proposing this AD to address the unsafe condition on these products.