AD 2011-26-10

final rule
Data completeness: 70%

Airworthiness Directives; Enstrom Helicopter Corporation Helicopters

AD Number
2011-26-10
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Docket No. FAA-2011-1382
FR Citation
77 FR 729

Applicability

TypeManufacturerModelDetails
aircraft Enstrom Helicopter Corporation Airworthiness Directives; Enstrom Helicopter Corporation Helicopters

Unsafe Condition

Failure of the cyclic trim system, specifically involving trim relays part-number KUP14D55-472, M83536/10-015M, or M83536/10-024M, which can lead to reduced controllability and potential loss of control of the helicopter.

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

Required Actions

Replace the actuator and limit switch bracket in the lateral and longitudinal trim actuator assemblies to provide a positive stop for the trim actuator. Perform operational (ground) and flight tests to verify the trim relay is functioning correctly after modification.

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

Compliance Time

Within 5 hours time-in-service (TIS) or at the next annual or 100 hour time-in-service inspection, whichever occurs first.

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

Affected Aircraft

Enstrom Helicopter Corporation Model F-28C, F-28C-2, F-28F, 280C, 280F, 280FX, TH-28, 480, and 480B helicopters equipped with trim relays part-number KUP14D55-472, M83536/10-015M, or M83536/10-024M.

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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