Airworthiness Directives; The Enstrom Helicopter Corporation Model F-28A, F-28C, F-28C2, F-28F, 280, 280C, 280F, and 280FX Series Helicopters

摘要

This amendment adopts a new airworthiness directive (AD) that is applicable to The Enstrom Helicopter Corporation (Enstrom) Model F- 28A, F-28C, F-28C2, F-28F, 280, 280C, 280F, and 280FX series helicopters. This action requires initial and repetitive inspections for delamination of the main rotor feathering elastomeric Lamiflex bearing (Lamiflex bearing). This amendment is prompted by several reported failures of the Lamiflex bearing. The actions specified in this AD are intended to prevent failure of the Lamiflex bearing, abnormal vibrations in the airframe and flight control system, and subsequent loss of control of the helicopter.