Main Rotor — Mast Upper Bearing Sealant Bead / Inner Race Retaining Rings — Inspection
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of affected AS 350, EC 130, and AS 355 helicopters must perform an initial inspection of the main rotor mast upper bearing sealant bead within specified flight hour limits and then repeat inspections every 165 flight hours until the retaining rings are verified. A detailed inspection of the retaining rings must be completed within 660 flight hours or 24 months from the effective date. Any discrepancies require immediate corrective action before further flight. Installation of affected parts is prohibited from the effective date.
Summary
EASA Airworthiness Directive 2018-0206 is an airworthiness directive issued by the European Aviation Safety Agency addressing Airbus Helicopters AS 350, EC 130, and AS 355 models. It mandates inspections of the main rotor mast upper bearing sealant bead and inner race retaining rings to ensure correct installation and prevent potential bearing failure. The directive applies to specific part numbers of the main rotor mast shafts and affects all serial numbers of the listed helicopter models.
What changed
This new airworthiness directive introduces mandatory one-time and repetitive inspections of the main rotor mast upper bearing sealant bead and inner race retaining rings. It requires operators to verify the correct installation of retaining rings and to perform corrective actions if discrepancies are found. The directive also prohibits installation of affected parts from the effective date onward.
Why it matters
This directive is critical for aviation professionals because missing or incorrectly installed retaining rings in the main rotor mast upper bearing can lead to bearing malfunction and potential loss of helicopter control. Compliance ensures continued airworthiness and safety of affected helicopters, preventing costly damage and operational disruptions. Maintenance and compliance teams must integrate these inspections into their schedules to meet regulatory requirements.
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