The Federal Aviation Administration (FAA) is adopting a new airworthiness directive (AD) for Bell Model 206L, 206L-1, 206L-3, and 206L-4 helicopters.
The AD is prompted by an investigation after an accident and the determination that there was a loose connection due to improper lock washer installation.
The AD requires inspecting certain hydraulic servo actuator assemblies for a loose nut, shaft, and clevis assembly, modifying or replacing the servo as necessary, and reidentifying the servo. These actions are intended to detect loose or misaligned parts of the servo to prevent failure of the servo and subsequent loss of control of the helicopter.
The FAA is also superseding four airworthiness directives related to the main rotor yoke on the Bell Model 204B, 205A, 205A-1, 205B, and 212 helicopters, to retain certain inspections and certain life limits, to require an increased inspection frequency for certain yokes, and to expand these inspections and retirement lives to other yokes.
The airworthiness directive is prompted by past reports of cracks in the yoke, another recent report of a cracked yoke, and the decision that other yokes, approved based on identicality, need to be subject to the same inspection requirements and retirement lives. The actions are intended to detect a crack in a yoke to prevent failure of the yoke, and subsequent loss of control of the helicopter.
