EASA Regulations for Airbus Helicopters MBB-BK117 A-4

EASA AD 2021-0122

Time Limits / Maintenance Checks — Airworthiness Limitation Section — Tension Torsion Straps — Storage Life Limit

EASA Airworthiness Directive 2021-0122 addresses the storage life limits of Tension Torsion (TT) Straps installed on Airbus Helicopters Deutschland GmbH MBB-BK117 helicopter models including A-1, A-3, A-4, B-1, B-2, C-1, C-2, and D-2. The directive focuses on the ageing of elastomeric materials in Bendix and Lord TT-Straps, which may compromise structural integrity and helicopter control. It mandates compliance with storage life limits and removal of certain Bendix TT-Straps to ensure continued airworthiness.