- Models
- 6A4-150-B3, 6A4-150-B31
- Data sheet
- TCDSE-238
- Registered aircraft
- 623 matched by model
- Product
- Engine
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| FAA DRS HTML | 20 KB | b20b8dd8…5e4c864 | FAA DRS (API key needed) |
On this page
The airworthiness directive
48-50-01 FRANKLIN: Applies to All Bellanca 14-13, 14-13-2 and Universal (Stinson) 108, 108-1 Aircraft Equipped With Franklin Model 6A4-150-B3 and B31 Engines With Serial Numbers 11000 to 14000 Inclusive. Compliance required after each 25 hours of operation. To prevent possible cylinder base flange failure, visual inspection for cracks just above the base flange should be made every 25 hours of operation on the early type cylinders until replaced by the later type cylinders. Early type cylinders have a flat section which extends 3/8 inch to 7/8 inch from the outer edge of the base flange. On later type cylinders the flat section has been practically eliminated by extending the ribbed section close to the edge of the flange. It is urgently recommended that early type cylinders be replaced at the earliest opportunity. (Franklin Service Bulletin No. 69 covers this same subject and offers special discounts effective through January 1949, for cylinder replacements). This supersedes AD 48-47-02.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 623
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1939 | 1 |
|---|---|
| 1940 | 1 |
| 1941 | 3 |
| 1943 | 2 |
| 1945 | 2 |
| 1946 | 302 |
| 1947 | 181 |
| 1948 | 3 |
| 1949 | 4 |
| 1950 | 1 |
| 1958 | 1 |
| 1970 | 1 |
| 1997 | 1 |
120 with no year recorded