AD 49-28-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; All Navion Airplanes Equipped With Product Techniques, Inc., Propeller Spinners |
| aircraft | Sierra Hotel Aero, Inc. | Navion A (Army L-17B and L-17C) | Airworthiness Directives; All Navion Airplanes Equipped With Product Techniques, Inc., Propeller Spinners |
Unsafe Condition
Unsatisfactory spinner bulkheads with thickness less than 0.045 inch at the perimeter may fail, leading to propeller spinner detachment.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect spinner bulkhead thickness at perimeter, 1/2 inch from edge. Replace bulkheads measuring less than 0.045 inch. Spinners with 0.058-inch or 0.064-inch cadmium plated steel bulkheads do not require inspections. Those with thinner steel or aluminum must be inspected and replaced if under 0.045 inch.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Before further flight, or within the next 50 hours of flight for spinners that passed previous inspections.
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) and Navion A (Army L-17B and L-17C) airplanes equipped with Product Techniques, Inc. propeller spinners.
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.