Tail Rotor Drive — Tail Rotor Drive Flange / Shaft Flexible Coupling — Inspection / Modification
- Published
- Effective
- Deadline
- Replaces
- 2020-0212
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must inspect the shur-lok nut of the tail rotor drive flange within 110 flight hours after 1 August 2014 for certain helicopter groups and perform corrective actions if discrepancies are found before the next flight. They must also modify the main gearbox tail rotor drive flange within 600 flight hours or a specified calendar time depending on the helicopter group, with deadlines ranging from 10 months to 12 months after the AD's effective date or previous AD effective dates. Additional modification actions apply to specific groups within the same compliance window.
Summary
EASA Airworthiness Directive 2020-0287 is an airworthiness directive affecting Airbus Helicopters models SA 365, AS 365, and EC 155 series. It addresses inspection and modification requirements for the tail rotor drive flange and shaft flexible coupling to prevent loosening of the shur-lok nut that retains the tail rotor drive flange on the main gearbox. The directive applies to helicopters with specific Airbus Helicopters modifications embodied and covers multiple groups of affected aircraft based on delivery dates and modification status.
What changed
EASA AD 2020-0287 supersedes AD 2020-0212 and expands the applicability to include all AS 365 N2, AS 365 N3, EC 155 B, and EC 155 B1 helicopters with modification 07 63B64 embodied, including those delivered from 9 July 2014 onwards. It retains previous inspection and modification requirements and introduces mandatory modification of the main gearbox tail rotor drive flange within specified flight hour or calendar time limits depending on the helicopter group. Additional modification actions are required for certain helicopter groups to ensure continued airworthiness.
Why it matters
This directive is critical for aviation professionals because failure to comply could result in loosening or disengagement of the tail rotor drive flange retaining nut, leading to reduced tail rotor drive control, increased vibrations, and compromised helicopter control. Operators and maintenance organizations must ensure timely inspections and modifications to maintain safety and regulatory compliance. The AD helps prevent potential in-flight failures and enhances the reliability of the tail rotor drive system.
More for Airbus Helicopters SA
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- EASA AD 2026-0118Rotors Flight Control – Tail Rotor Actuator – InspectionJun 22, 2026
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