AD 57-12-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Scotts-Bell 47 Inc | 47B | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47B3 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47D | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47D1 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G-2 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47H-1 | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47J | Airworthiness Directives; Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J Helicopters |
Unsafe Condition
Excessive play in the metal tail rotor blade and hub assembly and the pitch control mechanism can result in blade flutter.
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Required Actions
Inspect the metal tail rotor blade and hub assembly and pitch control mechanism as required in Part A of Bell Mandatory Service Bulletin No. 121SB. Inspect metal tail rotor blades P/N 47-642-102-5 for minimum 0.750 inch thickness at blade station 14.00; replace blades below this thickness.
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Compliance Time
as soon as possible but not later than August 1, 1957
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Affected Aircraft
Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, 47H1, and 47J helicopters with metal tail rotor blades (Part A); Bell Model 47B, 47B3, 47D, 47D1, 47G, 47G2, and 47H1 helicopters with metal tail rotor blades P/N 47-642-102-5 (Part B)
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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