Engine Bleed Air – Bleed-Off Valve (BOV) Failure to Close
Superseded. A newer version replaces this document.
- Published
- Effective
- Deadline
- Replaces
- 2021-20
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must inspect BOVs within 50 flight hours from June 1, 2021, for pre-modification engines and replace BOV assemblies within 100 flight hours from the AD's effective date of November 16, 2021. Repeated inspections are required if contamination is found, and ongoing inspections must be conducted within 650 flight hours or 12 months after BOV replacement.
Summary
The Canadian Airworthiness Directive CF-2021-37 addresses issues with Pratt & Whitney Canada PT6E-67XP engines, specifically those with serial number HP0138 and earlier. It mandates inspections and replacements of engine bleed air bleed-off valves (BOVs) to prevent failure to close due to contamination. This directive supersedes previous AD CF-2021-20 and related alternative means of compliance.
What changed
AD CF-2021-37 supersedes AD CF-2021-20 and cancels the AMOC AARDG-2021/A43. It requires compliance with updated Pratt & Whitney Canada Service Bulletins A75018 Revision 4 and 75020 Revision 1, which introduce a new BOV assembly design more tolerant to contamination and provide updated inspection instructions.
Why it matters
This directive is critical for aviation professionals because failure of the BOV to close properly can cause engines to underperform during high power demands, such as go-around maneuvers, posing safety risks. Operators and maintenance teams must ensure timely inspections and replacements to maintain engine reliability and regulatory compliance.
More for Pratt & Whitney Canada PT6A-67
All 5- EASA AD CF-2024-33Engine — First-Stage Power Turbine (PT1) Blade FailureSep 19, 2024
- EASA AD CF-2024-05Engine — Second-Stage Power Turbine (PT2) Blade FailureFeb 15, 2024
- EASA AD CF-2022-26Engine Bleed Air — Bleed-Off Valve Failure to CloseMay 18, 2022
- EASA AD CF-2021-20SUPERSEDED BY TCCA AD CF-2021-37May 19, 2021
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