57-08-01: Tail Rotor Drive Shafts
FAA order 57-08-01 is an airworthiness directive. The FAA's subject line: Tail Rotor Drive Shafts. It names Bell 47: about 478 aircraft on the U.S. register today, though an order usually covers particular versions or serial numbers rather than every one. System: rotorcraft systems.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Scotts-Bell 47 Inc
- Models
- 47, 47B, 47B3, 47D, 47D1, 47E, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, 47K
- On this site
- Bell 47 478 registered
Dates and paperwork
- Docket
- Unknown
- Status
- Current
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (1,222 characters)
57-08-01 BELL: Applies to All 47 Series Helicopters With Tail Rotor Drive Shafts, P/N 47-644-115-1, 47-644-126-3, 47-644-172-3, 47-644-177-1, 47-644-179-7, 47-644-180-1, 47-644- 186-1, 47-644-187-1, 47-644-187-5, and 46-644-214-1, Having Less Than 100 Hours Service Time and All Spares of These Part Numbers.
Compliance required as indicated.
Due to suspected defective materials, the listed tail rotor drive shafts must be inspected for evidence of longitudinal cracks, as follows:
1. Inspect all spare shafts by magnaflux methods immediately.
2. Shafts installed on helicopters and having less than 100 hours service time must be thoroughly cleaned and inspected daily with at least a 10-power magnifying glass, and inspected by magnaflux methods not later than the next 10 flying hours. The daily inspections may be discontinued upon completion of the magnaflux inspection.
3. Spare shafts and helicopters delivered from Bell after April 15, 1957, have these inspections accomplished and may be identified by a double interlocking magnaflux stamp in approximately the centers of the shafts.
(This AD covers the same inspections required by CAA telegraphic instructions, dated April 12 and 17, 1957.)
Related safety bulletins advice on the same designs, not orders
2001-02-09SW-01-13 ·
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 6, 2026. Connections as data: /graph/directive/57-08-01.json · aircraft systems.