AD 99-04-13
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bell Helicopter Textron, Inc. | 214ST | Airworthiness Directives; Bell Helicopter Textron, Inc. Model 214ST Helicopters |
Unsafe Condition
Fatigue failure of the tail rotor yoke due to external bending forces, which could result in failure of the yoke, loss of control of the tail rotor, and subsequent loss of control of the helicopter.
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Required Actions
Review historical records for incidents imposing bending loads on the yoke and replace the yoke if such history exists. Install a reduced Vne placard and incorporate the limitation into the Rotorcraft Flight Manual. Within 180 days, replace the yoke assembly with a zero-hours TIS airworthy yoke or one passing x-ray diffraction inspection, and install a frangible tail rotor flapping stop/yield indicator (P/N 214-011-809-109). Conduct repetitive 25 hours time-in-service inspections and inspections after incidents involving hard landings, sudden stoppage, or power on/off events to detect flapping stop damage.
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Compliance Time
Before further flight (for certain actions) and within 180 days (for others).
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Affected Aircraft
Bell Helicopter Textron, Inc. Model 214ST helicopters, serial numbers 28101 and higher.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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