[Correction] Fuselage — Tail Gearbox Fitting — Inspection / Replacement
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must perform a borescope inspection of the affected TGB fittings within 25 flight hours if the part has accumulated 3,000 or more flight hours, or within 25 flight hours after reaching 3,000 flight hours if less than that at the effective date. If cracks or discrepancies are found, the affected part must be replaced following Leonardo's instructions. Inspection results indicating cracks must be reported to Leonardo within 30 days. Reinstallation of affected parts is permitted only after inspection as required.
Summary
EASA Airworthiness Directive 2021-0259 is a safety directive addressing the inspection and possible replacement of tail gearbox (TGB) fittings, part numbers 3G5351A01151 and 3G5351A01152, on Leonardo AB139 and AW139 helicopters. The directive mandates a one-time borescope inspection of the affected TGB fittings to detect cracks that could compromise helicopter control. It applies to all serial numbers of the specified helicopter models.
What changed
This correction to EASA Airworthiness Directive 2021-0259 updates the reference to the data module in the Reason section of the directive. The directive introduces a requirement for borescope inspections of the inner forward-right side of the TGB fittings, which were previously inspected without this method, to better detect cracks.
Why it matters
This directive is critical for aviation professionals because undetected cracks in the TGB fittings can propagate to a critical length, potentially reducing the structural integrity of the tail gearbox and tail rotor. This condition could lead to reduced helicopter control, posing a significant safety risk. Operators and maintenance teams must comply to ensure continued airworthiness and safe operation of affected helicopters.
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