Airworthiness Directive: Mandatory Bolt Replacement on Airbus Helicopters MBB-BK 117 D-3 Flight Controls

The FAA has issued a new Airworthiness Directive (AD) targeting all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-3 helicopters. The directive was triggered by a manufacturing defect: certain bolts installed on the horizontal control rods of the flight control system were not subjected to dye penetrant inspection for cracks during the production process, leaving a potential structural weakness undetected. The failure to inspect these bolts raises the risk of bolt fracture during flight operations. Because the affected components are part of the primary flight control system, bolt failure could result in loss of helicopter control, posing a direct threat to the safety of occupants and people on the ground. To address this unsafe condition, the FAA is requiring operators to replace all affected bolts with bolts that have been verified as eligible for installation. Additionally, the directive permanently prohibits the reinstallation of any affected bolt on any helicopter covered by the AD, preventing recurrence of the defect. This AD is applicable to all MBB-BK 117 D-3 helicopters regardless of operational status, and compliance is mandatory under FAA regulations. Operators must act promptly to ensure continued airworthiness of their aircraft.

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