EASA AD No.: 2013

- 0177

TE. CAP.0011 0

- 00 3 © European Aviation Safety Agency. All rights reserved. 1 / 2 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. 

## EASA AIRWORTHINESS DIRECTIVE

AD No

. : 2013

- 0 177

Date: 08 August 2013

Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Community, its Member States and of the European third countries that participate in the activities of EASA under Article 66 of that Regulation.

This AD is issued in accordance with E U 748/2012 , Part 21

. A.3B. In accordan ce with EC 2042/2003 Annex I, Part M.A.301, the continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may ope rate an aircraft to which an AD applies, except in accordance with the requirements of that AD

, unless otherwise specified by the Agency [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216 / 2008 , Article 14 ( 4 ) exemption].



### Design Approval Holder’s Name:

AGUSTAWESTLAND S.p. A. 

### Type/Model designation(s):

AB139 and AW139 helicopters

TCDS Number: EASA.R.006

F oreign AD: Not applicable

Supersedure: None



### ATA 29 Hydraulic Power

– Flexible Hydraulic Hoses

– Replacement

Manufacturer(s): AgustaWestland S .p.A. (formerly Agusta S.p.A.) and AgustaWestland Philadelphia Corporation (formerly Agusta Aerospace Corporation)

Applicability: AB139 and AW139 helicopters

, all serial numbers

.

Reason: Occurrences of l eak ing hydraulic system flexible hoses have been reported

on in

- service helicopters

. The results of the subsequent technical investigation indicate that single braided flexible hydraulic hoses, which are part of the original AB/AW139 design, may have insufficient strength to cope with hydraulic system pressure pulsations over a long period.
This condition, if not corrected, could lead to other occurrences of hydraulic system leaks , possibly resulting in loss of hydraulic power and consequent reduced control of the helicopter

. To address this potential unsafe condition

, Agusta Westland introduced new flexible hydraulic hoses that are characterized by a “dual braided” design and published Bollettino Tecnico ( BT ) 139

- 307 , providing instructions for replacement of all hydraulic flexible hoses in service.
For the reasons described above, this AD require s replacement of flexible hydraulic hoses with improved parts

.

Effective Date: 22 August 2013EASA AD No.: 2013

- 0177

TE. CAP.0011 0

- 00 3 © European Aviation Safety Agency. All rights reserved. 2 / 2 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. Required A ction(s) and Compliance Time(s) : Required as indicated, unless accomplished previously: (1) For helicopters equipped with a flexible hydraulic hose having a Part Number (P/N) listed in Table 1 of this AD, within 300 flight hours or 6 months, whichever occurs first after the effective date of this AD, replace each affected flexible hydraulic hose with an improved flexible hydraulic hose in accordance with the instructions of AgustaWestland BT 139

- 307

.

Table 1

– Aff ected f lexible hydraulic hose s P/N

A494AE2E00E0670X

A494AE3E00E0424X

A494AE3E00E0530X

A494AE3E00E0570X

A494AE3E00E0580X

A494AE3E00E0620X

A494AE3E00E0930X

A494AE6E14E0348X

A494AE6E21E0330X

( 2 ) A fter modification of a helicopter as required by paragraph (1) of this AD, do not install a flexible hydraulic hose having a P/N listed in Table 1 of this AD on that helicopter

. ( 3 ) For a helicopter equipped only with flexible hydraulic hose s not having a P/N listed in Table 1 of this AD , from the effective date of this AD, do not install a flexible hydraulic hose having a P/N listed in Table 1 of this AD on that helicopter

.

Ref. Public ations: AgustaWestland BT 139

- 307 rev. / , dated 19 June 2013

. The use of later approved revisions of this document is acceptable for compliance with the requirements of this AD.

Remarks: 1. If requested and appropriately substantiated

, EASA can approve Alternative Methods of Compliance for this AD.

2. Based on the required actions and the compliance time, EASA have decided to issue a Final AD with Request for Comments, postponing the public consultation process until after publication.

3. Enquiries regarding this A D should be referred to the Safety Information Section, Executive Directorate , EASA. E

- mail : ADs@easa.europa.eu

. 4. For any question concerning the technical content of the requirements in this AD, please contact AgustaWestland S.p.A. : E

- mail: aw139.mbx@agustawestland.com

.