AD 52-13-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Aircraft Corporation | 49-46 | LOCKHEED Model 49 Series Airplanes |
Unsafe Condition
Inadvertent actuation of the propeller reversing solenoid valves due to lack of isolation from other electrical circuits, which could lead to unintended propeller reversal during flight operations.
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Required Actions
Implement circuit isolation modifications per Attachment A, install additional switches or comply with Hamilton Standard Service Bulletin No. 221, modify pedestal assemblies with stop pins and notches, conduct inspections and electrical checks at 350-hour intervals, and update operating instructions as specified.
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Compliance Time
Compliance required by November 1, 1953, with initial modifications starting no later than August 1, 1952.
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Affected Aircraft
Lockheed Aircraft Corporation Model 49-46 Constellation airplanes equipped with Hamilton Standard reversing propellers.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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