- Models
- 47B, 47B3, 47D, 47D1
- Data sheet
- TCDSH-1
- Registered aircraft
- 54 matched by model
- Product
- Aircraft · Rotorcraft
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 | 19 KB | 5d262909…3431f2b | FAA DRS (API key needed) |
On this page
The airworthiness directive
51-29-01 BELL: Applies to All Models 47B, 47B3, 47D, 47D1 Helicopters.
Compliance required as indicated.
1. Replace the tail rotor gearbox shaft, P/N 47-645-028-1 or 47-645-051-1, when it has accumulated 900 hours of operation.
2. Any shaft having already accumulated 900 hours of operation must be replaced by February 1, 1952. In the interim, conduct the following inspection after every 25 hours of operation: Remove tail rotor and inspect attachment bolt hole for cracks. Replace the shaft if a crack is found, or the hole is elongated over 0.010 inch.
(Bell Service Bulletin No. 83 covers this same subject.)
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 54
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1946 | 1 |
|---|---|
| 1947 | 7 |
| 1948 | 3 |
| 1949 | 3 |
| 1950 | 2 |
| 1951 | 6 |
| 1952 | 3 |
| 1953 | 2 |
| 1954 | 2 |
| 1955 | 1 |
| 1959 | 3 |
| 1960 | 1 |
| 1963 | 2 |
| 1964 | 1 |
| 1965 | 1 |
| 1966 | 1 |
| 1967 | 1 |
14 with no year recorded