AD 58-03-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hamilton Standard | Governors | HAMILTON STANDARD Governors |
Unsafe Condition
Missing oil hole sealing plugs in the governor body solenoid valve boss or oil leakage past the plugs can cause unwanted propeller reversals.
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Required Actions
Inspect for presence of oil hole plugs (PN 68753 for two-flyweight-type and PN 321736 for four-flyweight-type), install plugs as required. Install reworked solenoid valve mounting gasket (PN 322778 or 322779) with triangular cutout over plugged holes, or permanently vent the solenoid boss face via milling per Service Bulletin 536B. Identify inspected/reworked governors.
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Compliance Time
Prior to April 15, 1958 for governors with solenoid-electrical connection parallel to drive shaft axis (Position 1); at next governor overhaul for those with connections at right angles (Positions 2 and 4).
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Affected Aircraft
Hamilton Standard 4U18 and 5U18 Governors shipped from the factory prior to September 26, 1957.
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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