- Models
- 47B, 47B3, 47D, 47D1, 47G, 47G-2, 47H-1, 47J
- Registered aircraft
- 218 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 | 20 KB | 83c3e25f…4f74d62 | FAA DRS (API key needed) |
On this page
The airworthiness directive
57-12-04 BELL: Part A Below Applies to the Following Model 47 Helicopters Having Metal Tail Rotor Blades: 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J. Part B Below Applies to the Following 47 Helicopters Having Metal Tail Rotor Blades P/N 47-642-102-5; 47B, 47B3, 47D, 47D1, 47G, 47G2, and 47H1.
Compliance required as soon as possible but not later than August 1, 1957.
Part A. Due to the possibility of excessive play in the metal tail rotor blade and hub assembly and the pitch control mechanism which can result in blade flutter, the inspection as required in Part A of Bell Mandatory Service Bulletin No. 121SB, dated April 2, 1957, must be accomplished.
Part B. Metal tail rotor blades, P/N 47-642-102-5 should be inspected for proper thickness at blade station 14.00. This thickness should be a minimum of 0.750 inch at the thickest part of the blade. Blades measuring less than 0.750 inch are required to be removed and replaced with acceptable blades.
(Part B ofBell Mandatory Service Bulletin No. 121SB dated April 2, 1957, covers this same subject.)
Affected TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 218
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 | 10 |
| 1948 | 5 |
| 1949 | 3 |
| 1950 | 2 |
| 1951 | 7 |
| 1952 | 8 |
| 1953 | 8 |
| 1954 | 8 |
| 1955 | 7 |
| 1956 | 19 |
| 1957 | 18 |
| 1958 | 17 |
| 1959 | 10 |
| 1960 | 7 |
| 1962 | 1 |
| 1963 | 6 |
| 1964 | 1 |
| 1965 | 4 |
| 1966 | 1 |
| 1967 | 3 |
| 1968 | 1 |
| 1969 | 1 |
| 1972 | 1 |
| 1974 | 1 |
| 1975 | 2 |
| 1976 | 1 |
| 1979 | 1 |
| 1980 | 1 |
| 2010 | 1 |
62 with no year recorded