AD 52-21-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Scotts-Bell 47 Inc | 47 | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47B | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47B3 | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47D | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47D1 | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47E | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G-2 | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G-2A | Airworthiness Directives; Bell Model 47 Helicopters |
| aircraft | Scotts-Bell 47 Inc | 47G-2A-1 | Airworthiness Directives; Bell Model 47 Helicopters |
Unsafe Condition
Engine mount shifting on the rubber Lord mounts due to insufficient torque offset between engine mount clamp and rubber Lord mounts.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install two 47-612-123-1 guards on engine mounts for 178 HP engines (Models 47B, 47B3, 47D) to achieve a 5/32 inch torque offset. For 200 HP engines (all Models 47), inspect or replace guards with new type if ears are less than 3/16 inch to ensure 7/32 inch ears and 1/4 inch torque offset.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
October 15, 1952
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Bell Model 47 Helicopters: Models 47, 47B, 47B3, 47D, 47D1, 47E, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, and others as noted.
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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