EASA AD 2019-0165-E
Tail Rotor Drive — Tail Rotor Gearbox — Inspection / Replacement
Summary
EASA Airworthiness Directive 2019-0165-E is an emergency directive addressing the tail rotor gearbox (TGB) inspection and replacement requirements for Airbus Helicopters SA 365 N1, AS 365 N2, AS 365 N3, EC 155 B, and EC 155 B1 models. The directive mandates a one-time inspection of the TGB housing recess and oil duct cover to detect oil retention or foreign objects that could impair lubrication and control. It applies to all serial numbers of the affected helicopter models.
What Changed
This new emergency airworthiness directive introduces mandatory inspections of the tail rotor gearbox housing recess and oil duct cover within 55 flight hours or 5 months. It requires corrective actions including removal of foreign objects, re-inspection, and possible replacement of the TGB or its control rod bearing if defects are found. The directive also establishes that only serviceable TGB parts may be installed from the effective date onward.
Why It Matters
This directive is critical for aviation professionals because it addresses a potential unsafe condition that could reduce helicopter control due to lubrication failure in the tail rotor gearbox. Operators, maintenance organizations, and compliance teams must ensure timely inspections and corrective actions to maintain airworthiness and regulatory compliance. Failure to comply could lead to operational restrictions or safety risks.
What To Do
Operators must inspect the tail rotor gearbox housing recess for oil retention within 55 flight hours or 5 months from 2019-07-16. If oil retention or foreign objects are found, they must remove obstructions, re-inspect, and if necessary, replace the gearbox or control rod bearing before the next flight. Only serviceable tail rotor gearboxes may be installed on affected helicopters from the effective date.
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