Tail Rotor Drive — Flexible Couplings and Tail Rotor Shafts — Inspection
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of EC135 and EC635 helicopters with serial numbers up to 2212 must perform the axial displacement inspection within 100 flight hours or 12 months from 2023-11-24, whichever occurs first. If displacement thresholds are exceeded, flexible couplings must be inspected and replaced as necessary before further flight. Additionally, all tail rotor drive shaft installations must follow updated procedures from the effective date.
Summary
EASA Airworthiness Directive 2023-0197 is an airworthiness directive issued by the European Union Aviation Safety Agency affecting Airbus Helicopters Deutschland GmbH EC135 and EC635 helicopter models. It mandates inspection of the tail rotor drive flexible couplings and tail rotor shafts due to reported occurrences of ruptured or deformed flexible couplings. The directive applies to all variants and serial numbers of the specified helicopter models.
What changed
This new airworthiness directive introduces a one-time inspection requirement for axial displacement of the tail rotor drive shaft and, depending on the results, inspection and possible replacement of flexible couplings. It also establishes updated installation procedures for tail rotor drive shafts to prevent excessive axial displacement and related damage.
Why it matters
This directive is critical for aviation professionals because undetected cracks or deformation in the flexible couplings can cause high vibration in the tail rotor drive shaft, potentially reducing helicopter control. Compliance ensures continued airworthiness and safety of affected helicopters, helping operators and maintenance organizations avoid in-flight failures and costly repairs.
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