AD 47-21-10

final rule
Data completeness: 60%

Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through HAV-4-1010 Which Incorporate Hartzell HC-12X20-1 Propellers.

AD Number
47-21-10
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Sierra Hotel Aero, Inc. Navion (Army L-17A) Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through HAV-4-1010 Which Incorporate Hartzell HC-12X20-1 Propellers.

Unsafe Condition

The propeller control piston guide pins, Hartzell P/N A-11, may loosen and cause subsequent loss of engine oil.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Install a 3/32-inch steel dowel through the guide pin to safety the propeller control piston guide pins.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

not later than September 1, 1947

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Sierra Hotel Aero, Inc. Navion (Army L-17A) serial numbers NAV-4-2 through HAV-4-1010 incorporating Hartzell HC-12X20-1 propellers.

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

This site is not affiliated with or endorsed by the FAA. Always verify with official sources.

View Official Source ↗ Find More ADs for Sierra Hotel Aero, Inc. Navion (Army L-17A)

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