EASA AD No.: 2015

- 0 155

TE. CAP.0011 0

- 00 4 © 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

. : 20 15

- 0155

Date: 28 July 2015

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 EU 748/2012, Part 21.A.3B. In accordance with EU 1321/2014 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 [EU 1321/2014 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) exempt ion]

. 

### 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 : No ne



### ATA 30 Ice and Rain Protection

– F ull I ce P rotection S ystem T ail R otor S lip
R ing

– I nspection / Replacement

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

.

Applicability: AB139 and AW139 helicopters, all serial numbers ( S/N)

, if equipped with Full Icing Protection System (FIPS)

. Note 1 : Helicopters equipped with FIPS and have one of the kits “ Partial Removal Arrangement ” with Part Number (P/N) from 4G3000F00311 to P/N 4G3000F00319 inclusive are affected by the requirements of this AD.

Reason: A report was received that, d uring an inspection accomplished on the t ail r otor (TR) slip r ing of a n AW139 helicopter

, the TR s lip r ing body was found detached from the supporting flange

. T he screws connecting the mounting flange and the slip ring body were found loose and broken. A s i milar event was reported on another AW139 helicopter where, d uring a scheduled inspection, three screws were found missing from the TR s lip r ing , which was partially loose from the tail rotor gearbox support

. S ubsequent technical investigation revealed that the torque of the screws was improperly low

. The TR slip ring manufacturer established that this had been

cause d on the production line b y im proper installation of the affected screws on a number of TR s lip r ings.

This condition, if not detected and corrected, could lead to other events of detachment of the TR s lip r ing, possibly resulting in reduced control of the hel i copter

.EASA AD No.: 2015

- 0 155

TE. CAP.0011 0

- 00 4 © European Aviation Safety Agency. All rights reserved. 2 / 2 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. To address this potential unsafe condition, AgustaWestland (AW) published Bollettino Tecnico (BT) 139

- 404 , providing inspection and replacement instructions for the affected TR slip r ing s

. For the reasons described above, this AD requires identification and a

one

- time inspection of the affected slip ring s and, depending on findings, accomplishment of applicable corrective action(s).

Effective Date: 11 August 2015

Required A ction(s) and Compliance Time(s) : Required as indicated , unless accomplished previously :
Note 2: For the purpose of this AD, an affected TR slip ring has a P/N 4G6420V00151 or P/N 4G6420V00152 or P/N 4G6420V00153, except if this TR slip ring has a “T” marked after the S/N

, or if “MOD 1” is marked o n the manufacturing (MFG) plate.

(1) Within 14 days after the effective date of this AD, inspect each affected TR slip ring in accordance with the instructions of AgustaWestland BT 139

- 404

. (2) If, during the inspection as required by paragraph ( 1 ) of this AD, no discrepancy is found on a TR slip ring, before next flight, replace the mounting screws

, re

- install the lockwire and re

- identify the TR slip ring in accordance with the instructions of AgustaWestland BT 139

- 404

. ( 3 ) If, during the inspection as required by paragraph ( 1 ) of this AD, a discrepancy is found on a TR slip ring, before next flight, replace it with a serviceable part in accordance with the instructions of AgustaWestland BT
139

- 404

. Note 3: For the purpose of this AD, a serviceable part is a TR slip ring which is not affected by this AD

– see Note 2 of this AD

. Condition for installation of a TR slip ring on a helicopter:

( 4 ) F rom the effective date of this AD, install ation of a TR slip ring is allowed, provided it is a serviceable part as defined in Note 3 of this AD

.

Ref. Public ations: Agusta Westland BT 139

- 404 original issue dated 22 December 2014.

The use of later approved revisions of th is 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 AD should be referred to the Safety Information Section, Certification Directorate, EASA. E

- mail: ADs@easa.europa.eu

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

- mail: aw139.mbx@agustawestland.com

.