Engine Bleed Air — Bleed-Off Valve Failure to Close
- Published
- Effective
- Deadline
- Replaces
- 2021-37
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of PT6E-67XP engines with serial numbers HP0138 and earlier must replace the BOV assembly and install the new BOV orifice feed air tube assembly with P3 probe snorkel within 50 hours air time from May 26, 2022. For engines serial numbered HP0194 and earlier that have incorporated SB 75020 but not SB 75025, the new assembly must be installed within 600 hours air time or 12 months from the effective date. Compliance with the specified P&WC Service Bulletins is mandatory.
Summary
Airworthiness Directive CF-2022-26 addresses a safety issue with Pratt & Whitney Canada PT6E-67XP engines, specifically those with serial numbers HP0194 and earlier. The directive focuses on the failure of engine bleed air bleed-off valves (BOVs) to close properly, which can cause engines to fail to achieve required power during high power applications. This directive supersedes previous AD CF-2021-37 and mandates inspections, cleaning, and design modifications to improve valve reliability.
What changed
CF-2022-26 supersedes AD CF-2021-37 and introduces mandatory incorporation of a new BOV orifice feed air tube assembly with a P3 probe snorkel, as described in P&WC Service Bulletin 75025 Revision 3. It also requires replacement of the BOV assembly with a more contamination-tolerant design per SB 75020. These changes terminate previous inspection requirements and enhance contamination resistance.
Why it matters
This directive is critical for aviation professionals to prevent engine power loss during critical flight phases such as go-around maneuvers. Operators and maintenance organizations must comply to ensure engine reliability and safety, avoiding hazardous conditions caused by contaminated bleed-off valves. Compliance also ensures adherence to Canadian Aviation Regulations and avoids grounding of affected aircraft.
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-2021-37Engine Bleed Air – Bleed-Off Valve (BOV) Failure to CloseNov 9, 2021
- EASA AD CF-2021-20SUPERSEDED BY TCCA AD CF-2021-37May 19, 2021
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