Airworthiness Directives; MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain 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 AD was prompted by laboratory tests that showed that the oxygen tubes of the crew oxygen system may be contaminated with lubricants, as a result of the manufacturing and cleaning procedures used. This AD requires cleaning and flushing the crew oxygen system. The FAA is issuing this AD to address the unsafe condition on these products.