AD 88-04-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 767-200 Series | Airworthiness Directives; BOEING Model 767 Series Airplanes |
| aircraft | The Boeing Company | 767-300 Series | Airworthiness Directives; BOEING Model 767 Series Airplanes |
| aircraft | The Boeing Company | 767-300F Series | Airworthiness Directives; BOEING Model 767 Series Airplanes |
Unsafe Condition
Failure of the pneumatic system 8th stage check valve could cause engine or pneumatic system damage.
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Required Actions
Inspect the pneumatic system 8th stage check valves on both engines within 6 months after the effective date. If valves are identified by serial number as requiring further inspection, remove them, inspect the valve retention collar, and modify as necessary prior to further flight. Valves not installed must be inspected and modified prior to installation.
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Compliance Time
within the next 6 months after the effective date of this AD
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Affected Aircraft
Boeing Model 767 series airplanes listed in Boeing Service Bulletin 767-36-0021, dated September 17, 1987, certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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