Proposed rule · 2025-06367

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

The FAA proposes to adopt a new airworthiness directive (AD) for all MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), Model CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000). This proposed AD was prompted by an engine indicating and crew alerting system (EICAS) STAB TRIM Caution message that was posted, and subsequent repair that found prematurely worn teeth on a rubber bull gear (RBG) wheel in the horizontal stabilizer trim actuator (HSTA). This proposed AD would require an inspection for part numbers and on-condition replacement of affected RBG wheels and prohibit the installation of affected parts under certain conditions, as specified in a Transport Canada AD, which is proposed for incorporation by reference (IBR). The FAA is proposing this AD to address the unsafe condition on these products.