AD 2021-04-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Robinson | Helicopter Company | Airworthiness Directives; Robinson Helicopter Company Helicopters |
Unsafe Condition
Reports of tail rotor (T/R) drive shaft forward hanger bearing failures due to the bearing spinning at a speed that caused excessive heating of the bearing during operation and led to the breakdown of the bearing's grease and ultimately seizure of the C647-16 bearing.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Installing a certain part-numbered kit and removing parts from service or replacing a certain part-numbered T/R drive shaft assembly. The FAA also prohibits the installation of certain parts.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 100 hours time-in-service (TIS)
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Affected Aircraft
Robinson Model R66 helicopters with a T/R drive shaft assembly part number (P/N) D224-3 without B900-11 modification installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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