AD 90-12-02
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 can cause engine or pneumatic system damage.
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Required Actions
Inspect the 8th stage bleed pneumatic system check valve per Hamilton Standard Service Bulletin 36-2078 or Revision 1. Repair or replace valves that fail inspection. Thereafter, inspect the check valve poppet every 1,200 hours time-in-service.
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Compliance Time
Within the next 500 hours time-in-service after March 19, 1990, or prior to 1,200 hours time-in-service on the valve, or within 30 days after June 18, 1990, whichever occurs later.
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Affected Aircraft
Boeing Model 767 series airplanes equipped with Hamilton Standard 8th stage bleed pneumatic system check valve, part number 773856.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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