AD 90-23-10
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | DC-9-81 (MD-81) | Airworthiness Directives; MCDONNELL DOUGLAS DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) Series Airplanes and MD-88 Airplanes |
| aircraft | The Boeing Company | DC-9-82 (MD-82) | Airworthiness Directives; MCDONNELL DOUGLAS DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) Series Airplanes and MD-88 Airplanes |
| aircraft | The Boeing Company | DC-9-83 (MD-83) | Airworthiness Directives; MCDONNELL DOUGLAS DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) Series Airplanes and MD-88 Airplanes |
| aircraft | The Boeing Company | DC-9-87 (MD-87) | Airworthiness Directives; MCDONNELL DOUGLAS DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) Series Airplanes and MD-88 Airplanes |
| aircraft | The Boeing Company | MD-88 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) Series Airplanes and MD-88 Airplanes |
Unsafe Condition
Dual hydraulic system failure due to Whittaker Controls PTU shutoff valve (P/N 240695 or 240695-1) failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace PTU S/O valve attachment screws with P/N NAS 1101E-14; replace PTU S/O valve P/N 240695/240695-1 with P/N 240695-2 or modify via specified service bulletins. Compliance timelines vary based on valve part number.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 90 days or 180 days after December 10, 1990, depending on valve part number. For P/N 240695, also prior to 2,000 landings or within 200 landings after October 23, 1989, whichever is later.
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Affected Aircraft
MCDONNELL DOUGLAS DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87) series and MD-88 airplanes with Whittaker Controls PTU S/O valve P/N 240695, 240695-1, or 240695-2.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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