EASA SIB CASA-2023-03
Safety Valve — Opening During Normal Operation and Ingestion of Insulation Blankets
Summary
The Transport Canada Civil Aviation Safety Alert CASA 2023-03 addresses issues related to the safety valve (SFV) on MHI RJ Aviation CRJ 550/700/701/702/705/900 aeroplanes. It highlights problems with the inadvertent opening of the SFV during normal operation due to positive pressure mechanism drift and insulation blanket ingress causing valve sticking. The alert informs operators and maintainers about updated parts and maintenance procedures to mitigate these issues.
What Changed
CASA 2023-03 introduces the replacement of the SFV part number GG670-98005-1 with an improved version GG698-98005-1, which resolves the pressure threshold drift issue. Additionally, the Aircraft Illustrated Parts Catalogue (AIPC) and Aircraft Maintenance Manual (AMM) have been updated to emphasize proper installation of insulation blankets near the SFV to prevent ingress and valve malfunction. These updates were published in June 2023.
Why It Matters
This alert is critical for aviation professionals because inadvertent SFV opening and valve sticking increase crew workload and can lead to false CABIN ALT warnings, potentially affecting flight safety. Proper installation and timely replacement of affected parts ensure the reliability of pressurization safety systems on CRJ aircraft. Compliance helps maintain operational safety and reduces maintenance complications.
What To Do
Operators, maintainers, and maintenance specialists must carefully follow the updated Aircraft Maintenance Manual instructions for installing insulation blankets near the SFV. They should replace SFV parts GG670-98005-1 with the improved GG698-98005-1 as per the revised Aircraft Illustrated Parts Catalogue. Personnel must apply the latest removal and installation procedures to prevent valve malfunction. No specific compliance deadline is stated.