AD 59-06-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion A (Army L-17B and L-17C) | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion B | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
| aircraft | Sierra Hotel Aero, Inc. | Navion D | Airworthiness Directives; Tusco Corporation (Navion) Applies to All Models |
Unsafe Condition
Failures of hydraulic actuating cylinders causing loss of flaps and landing gear collapse.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect flap and landing gear actuating cylinders for cracks and replace if any are found. Adjust hydraulic system pressure relief valve to 1125+25, -0 p.s.i. Install hydraulic fluid restrictors in nose gear lines (Serial Numbers 1271 and subsequent), main gear lines (Serial Numbers 1790 and subsequent), and flap lines (all serial numbers). Inspect linkage adjustments of landing gear bungee springs and flap stops to ensure proper alignment per service manuals.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
by May 1, 1959, and at each periodic inspection thereafter
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Tusco Corporation Navion models: Navion (Army L-17A), Navion A (Army L-17B and L-17C), Navion B, Navion D, with serial number ranges specified for restrictors: nose gear lines (1271 and subsequent), main gear lines (1790 and subsequent), and flap lines (all serial numbers)
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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