Hydraulic Power — Tail Rotor Load Compensator — Functional Check / Modification
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must immediately cease hydraulic off training as specified in the Flight Manual Supplement SUP.7 and place a cockpit placard to that effect. Within 15 flight hours or 7 days from 11 May 2021, a functional check of the hydraulic solenoids must be performed. If faults are found, corrective wiring modifications must be done before the next flight. All affected helicopters must be modified within 150 flight hours or by the effective date plus 150 flight hours, whichever is later, to fully comply with the AD.
Summary
EASA Airworthiness Directive 2021-0123-E is an emergency directive affecting Airbus Helicopters AS 350 B, B2, B3, and BA models with specific serial numbers. It addresses a wiring non-conformity in the tail rotor load compensator hydraulic system that could lead to loss of hydraulic power and potential loss of helicopter control. The directive mandates a functional check and modification of the hydraulic system wiring to ensure safe operation.
What changed
This new emergency AD introduces a prohibition on hydraulic off training and requires a one-time functional check of the main rotor and tail rotor servo actuator solenoids. If discrepancies are found, corrective wiring modifications using a retrofit kit must be performed. Additionally, all affected helicopters must be modified within 150 flight hours to correct the wiring issue.
Why it matters
This directive is critical for aviation professionals because it addresses a safety risk that could cause loss of tail rotor hydraulic control during emergency procedures or training. Operators and maintenance teams must comply to prevent potential loss of helicopter control, ensuring continued airworthiness and regulatory compliance. The operational restriction on hydraulic off training impacts pilot training programs until compliance is achieved.
More for Airbus Helicopters AS 350
All 99- EASA AD 2025-0159R1Placards and Markings – Unlock Sliding Door – InstallationOct 19, 2026
- EASA AD 2026-0052R2Instruments – Fuse Cover Attachment of Circuit Breaker Panel – ModificationSep 24, 2026
- EASA AD 2023-0214R1Fuselage – Tail Rotor Drive Shaft / Rear Transmission Bearing Support – Inspections / ModificationSep 16, 2026
- EASA AD 2024-0144R1Tail Rotor Drive – Shaft-Line – Check / Measurement / ModificationSep 16, 2026
- EASA AD 2026-0146
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