AD 2021-22-11
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | MD | Various | Airworthiness Directives; MD Helicopters Inc. (MDHI) Helicopters |
Unsafe Condition
A report of a spiral crack in the pilot-to-copilot tail rotor torque tube (torque tube) that appears to have originated from a hole where the tail rotor torque tube control fitting attaches to the torque tube on a Model 369FF helicopter. This crack resulted in increased left pedal movement and subsequent reduced directional control pedal authority. Other model helicopters are affected due to design similarity. This condition, if not addressed, could result in failure of the torque tube, loss of tail rotor control, and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Visually inspect the torque tube exterior using a flashlight and mirror and borescope inspect the interface of the torque tube and bushing segments for a crack, elongation, and other damage. If there is a crack, elongation, or other damage, remove the torque tube from service. Repeat the borescope inspection at intervals not to exceed 300 hours TIS. If the torque tube is removed from service, do not return it to service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 100 hours TIS after the effective date of this AD, or within 5 hours TIS or 30 days after the effective date of this AD, whichever occurs later, for helicopters that have accumulated more than 600 total hours TIS.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
MD Helicopters Inc. (MDHI) Model 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, with pilot-to-copilot tail rotor torque tube (torque tube) part number 369H7531-9/-11/-13, 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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