AD 89-23-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 757-200 Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
| aircraft | The Boeing Company | 757-200CB Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
| aircraft | The Boeing Company | 757-200PF Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
| aircraft | The Boeing Company | 757-300 Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
| aircraft | The Boeing Company | 767-200 Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
| aircraft | The Boeing Company | 767-300 Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
| aircraft | The Boeing Company | 767-300F Series | Airworthiness Directives; BOEING Model 757 and 767 Series Airplanes |
Unsafe Condition
Possible complete loss of hydraulic power due to potential failure of the Ram Air Turbine (RAT) hydraulic pump when the RAT Ground Checkout Module (GCM) is not properly reworked or replaced.
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Required Actions
Remove and rework or replace the RAT Ground Checkout Module (GCM) per applicable Boeing Service Bulletins. Inspect the downstream filter screen of the removed GCM before returning to service. If the screen is damaged, missing, or previously not inspected, test or replace the RAT hydraulic pump prior to further flight. Replace the pump if it is damaged during testing.
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Compliance Time
within the next 6,000 hours time-in-service after the effective date of this AD
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Affected Aircraft
Boeing Model 757 and 767 series airplanes listed in Boeing Alert Service Bulletins 757-29A0037, Revision 1, and 767-29A0035, Revision 1, both dated November 23, 1988.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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