AD Amdt-39-10421

Recurring final rule
Data completeness: 70%

Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 Helicopters and Agusta S.p.A. Model AB412 Helicopters

AD Number
Amdt-39-10421
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Docket No. 97-SW-58-AD
FR Citation
63 FR 14026

Applicability

TypeManufacturerModelDetails
aircraft Textron Various Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 Helicopters and Agusta S.p.A. Model AB412 Helicopters
aircraft Bell Helicopter Textron Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 Helicopters and Agusta S.p.A. Model AB412 Helicopters

Unsafe Condition

Fatigue damage to the tail rotor yoke assembly due to unforeseen static and dynamic loading against the original flapping stop.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Reduce the never-exceed velocity (Vne) limitation temporarily. Inspect the tail rotor yoke assembly for fatigue damage and install a redesigned yoke flapping stop. Perform recurring periodic and special inspections to detect yoke overload occurrences.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Before further flight

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Bell Helicopter Textron Model 412 and Agusta S.p.A. Model AB412 helicopters.

AI-generated summary from the source AD text. Verify against the official source before acting.

Source: Official FAA Source ↗

Retrieved: Apr 6, 2026

Rights: U.S. Government Public Domain

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