EASA SIB CASA-2020-10: Bombardier Inc. CL-600-2B19 Aeroplanes - Horizontal Stabilizer Fitting - Loose Bolts

What to do

Operators and maintenance personnel should perform the detailed inspection as per the updated task card #000-55-320-517, checking each mounting bolt for looseness using a wrench with specified torque values. If loose bolts are found, inspect bolt holes for dimensional tolerance and carry out repairs or replacements as recommended, including submitting Service Difficulty Reports to Transport Canada for any findings. No specific compliance deadline is stated, but inspections should be conducted promptly to maintain safety.

Summary

Transport Canada Civil Aviation Safety Alert CASA 2020-10 addresses the issue of loose mounting bolts on the horizontal stabilizer forward steady fitting of Bombardier Inc. CL-600-2B19 aeroplanes, including Canadian Regional Jet (CRJ) 100/200/440 series and Challenger CL850 series. The alert highlights the risk of undetected loose bolts during scheduled maintenance inspections, which can lead to structural concerns and reduced flutter damping system effectiveness.

What changed

This new safety alert introduces a recommended inspection procedure to detect looseness in the horizontal stabilizer forward steady fitting bolts. It includes a tactile check step added to Bombardier's task card #000-55-320-517 and provides detailed guidance on inspecting, repairing, or replacing bolts and bolt holes if looseness or dimensional tolerance issues are found.

Why it matters

Loose bolts in the horizontal stabilizer fitting can cause structural overload due to asymmetric loads and reduce the effectiveness of the flutter damping system, potentially compromising flight safety. Operators, maintainers, and inspectors need to be aware of this issue to prevent undetected damage and ensure continued airworthiness of affected Bombardier CRJ and Challenger aircraft.