EASA AD 2021-0160
Main Rotor System — Flex Control Unit Bearing Pin — Inspection / Modification
Summary
EASA Airworthiness Directive 2021-0160 is an airworthiness directive issued by the European Union Aviation Safety Agency concerning Airbus Helicopters Deutschland GmbH MBB-BK117 D-3 helicopters, including converted MBB-BK117 D-2 models. The directive addresses inspection and modification requirements for the main rotor system's flex control unit bearing pin to prevent potential unsafe conditions.
What Changed
EASA Airworthiness Directive 2021-0160 introduces a one-time inspection and corrective action requirement for affected flex control units and bearing pins on MBB-BK117 D-3 helicopters. It mandates reworking or replacement of affected bearing pins and prohibits installation of affected parts from the effective date. This is a new regulation addressing a specific unsafe condition related to bearing pin clamping.
Why It Matters
This directive is critical for aviation professionals because it addresses a potential unbalance in the main rotor system that could cause excessive vibration and reduced helicopter control. Operators, maintenance organizations, and compliance teams must ensure inspections and modifications are completed to maintain airworthiness and safety. Failure to comply could lead to operational restrictions or safety risks.
What To Do
Operators of MBB-BK117 D-3 helicopters must inspect affected flex control units within 55 flight hours from 2021-07-19 and perform corrective actions if discrepancies are found. Affected bearing pins must be reworked or replaced before the next flight after inspection. Installation of affected parts is prohibited from the effective date, and installation of a specified hexagonal screw is allowed following the prescribed instructions.
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