# Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters
> **Rule** · Final rule. · Published 2021-05-20 · Effective 2021-06-24 · 86 FR 27268
## Document
- **Document number:** 2021-10605
- **Category:** airworthiness
- **Manufacturer:** Airbus
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 86 FR 27268
- **Publication date:** 2021-05-20
- **Effective date:** 2021-06-24
- **FAA docket:** Docket No. FAA-2021-0143
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Helicopters Deutschland GmbH Model BO-105A, BO-105C, BO- 105S, and BO-105LS A-3 helicopters. This AD was prompted by the FAA's determination that aging of the elastomeric material in a tension torsion strap (TT-strap) could affect the structural characteristics of the TT-strap. This AD requires replacement of certain TT-straps with serviceable parts and implementation of a new storage life limit for TT-straps, as specified in a European Aviation Safety Agency (now European Union Aviation Safety Agency) (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/05/20/2021-10605/airworthiness-directives-airbus-helicopters-deutschland-gmbh-helicopters)
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