AD 48-50-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Wytwornia Sprzetu Komunikacyjnego | 6A4-150-B3 | FRANKLIN Model 6A4-150-B3 and B31 Engines |
| engine | Wytwornia Sprzetu Komunikacyjnego | 6A4-150-B31 | FRANKLIN Model 6A4-150-B3 and B31 Engines |
Unsafe Condition
Cylinder base flange failure due to cracks just above the base flange on early type cylinders with a flat section extending 3/8 inch to 7/8 inch from the outer edge.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect visually for cracks just above the base flange every 25 hours of operation. Replace early type cylinders with later type cylinders (with reduced flat section near the flange) at the earliest opportunity.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
after each 25 hours of operation
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Affected Aircraft
Bellanca 14-13, 14-13-2 and Universal (Stinson) 108, 108-1 AD-equipped aircraft with Franklin Model 6A4-150-B3 and B31 engines, serial numbers 11000 to 14000 inclusive.
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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