EASA AD No.: 2014-0257R1

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EASA AIRWORTHINESS DIRECTIVE

AD No.: 2014-0257R1

Date: 29 May 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 operate 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) exemption].

Design Approval Holder’s Name:

AIRBUS

Type/Model designation(s):

A330 and A340 aeroplanes

TCDS Numbers: EASA.A.004 and EASA.A.015

Foreign AD: Not applicable

Revision: This AD revises EASA AD 2014-0257 dated 27 November 2014.

ATA 27 Flight Controls – Trimmable Horizontal Stabilizer Actuator –

Identification / Replacement

Manufacturer(s): Airbus (formerly Airbus Industrie)

Applicability: Airbus A330-201, A330-202, A330-203, A330-223, A330-223F, A330-243, A330-

243F, A330-301, A330-302, A330-303, A330-321, A330-322, A330-323, A330-

341, A330-342 and A330-343 aeroplanes, all manufacturer serial numbers 

(MSN).

Airbus A340-211, A340-212, A340-213, A340-311, A340-312, A340-313,

A340-541, A340-542, A340-642 and A340-643 aeroplanes, all MSN.

Reason: During endurance qualification tests on Trimmable Horizontal Stabilizer Actuator 

(THSA) of another Airbus aeroplane type, a partial loss of the no-back brake 

(NBB) efficiency was experienced. Due to THSA design similarity on the 

A330/A340 fleet, a similar partial loss of the NBB efficiency was identified on 

THSA Part Number (P/N) 47147 as installed on A330-300 and A340-200/-300

aeroplanes, on THSA P/N 47172 as installed on A330-200/-300 and A340-200/-

300 aeroplanes, and on THSA P/N 47175 as installed on A340-500/600

aeroplanes. 

Investigation results concluded that this partial loss of braking efficiency in some 

specific aerodynamic load conditions was due to polishing and autocontamination of the NBB carbon friction disks. 

This condition, if not detected and corrected and in conjunction with the power 

gear train not able to keep the ball screw in its last commanded position, could 

lead to uncommanded movements of the THS, possibly resulting in loss of control 

of the aeroplane.
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To address this potential unsafe condition, EASA issued AD 2013-0144 to require 

replacement of each THSA that has exceeded 16 000 flight cycles (FC) in

service, to be sent in shop for NBB carbon disk replacement.

Since that AD was issued, a need for clarification has been demonstrated,

regarding the identification of the THSA ‘affected’ by this requirement.

For this reason, EASA AD 2013-0144 was revised, confirming that this AD only 

affected those THSA identified by Part Number (P/N) in Airbus Alert Operator 

Transmission (AOT) A27L005-13. In addition, a note was added to make clear

that the life limits as specified in the current revision of ALS Part 4 are still 

relevant for the affected THSA, as applicable to aeroplane model and THSA P/N.

Since EASA AD 2013-0144R1 was issued, further assessment of the ageing / 

endurance issue has resulted in the conclusion that there is a need to replace the

NBB installed on the THSA.

Consequently, EASA issued AD 2014-0257, which retained the requirements of 

EASA AD 2013-0144R1, which was superseded, and required removal from 

service of affected THSA. THSA should be sent in shop for NBB carbon disk 

replacement. This AD affected additional THSA P/N when compared to EASA AD 

2013-0144R1 and Airbus AOT A27L005-13.

Since that AD was issued, it was determined that it is necessary to consider that 

the THSA removal for NBB disks replacement could also be calculated since last 

NBB disk replacement which was done in-shop.

Effective date: Revision 1: 05 June 2015

Original issue: 11 December 2014

Required Action(s) 

and Compliance

Time(s):

Required as indicated, unless accomplished previously:

Note 1: The THSA affected by the requirements of this AD are those identified in 

Table 1 of this AD.

Table 1 – Affected THSA P/N

Aeroplane THSA P/N

A330 and

A340-200/-300

47147-500, 47147-700

47172-300, 47172-500, 47172-510, 47172-520

A340-500/-600 47175-200, 47175-300, 47175-500, 47175-520

Note 2: For the purpose of this AD, a serviceable THSA is a THSA having a P/N 

as identified in Table 1 of this AD and which has not exceeded the limits identified 

in this AD, or a THSA with a different P/N, not affected by the requirements of this 

AD.

Note 3: The THSA life limits as specified in the current revision of ALS Part 4 are 

still relevant, as applicable to aeroplane model and THSA P/N.

Note 4: A review of the aeroplane delivery or maintenance records is acceptable 

for the P/N determination in lieu of the inspection as specified in the applicable 

Airbus SB, provided that the aeroplane configuration and installed components 

can be conclusively determined from that review.

Part A - For A330 and A340-200/-300 aeroplanes

(1) Within the compliance time as specified in Table 2 of this AD, depending on 

the FC accumulated by the THSA on 31 July 2013 [the effective date of 

EASA AD 2013-0144 at original issue], but not later than the thresholds

specified in Table 3 of this AD, depending on the FC accumulated by the 

THSA on each corresponding date specified in Table 3 of this AD, replace 

each affected THSA with a serviceable unit in accordance with the 

instructions of Airbus SB A330-27-3199 or SBA340-27-4190 as applicable to 

aeroplane type and model.
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Table 2

FC accumulated by the THSA on 31 July 

2013 (the effective date of the original 

issue of EASA AD 2013-0144) since first 

installation on an aeroplane, or since last

NBB replacement, whichever is later

Compliance Time

20 000 FC or more within 1 500 FC after

31 July 2013 

16 000 FC or more, but less than 20 000 

FC

A330: within 4 000 FC 

after 31 July 2013

A340: within 3 000 FC 

after 31 July 2013

Less than 16 000 FC as specified in paragraph 

(2) of this AD

(2) Not later than the date specified in Table 3 of this AD, as applicable,

for THSA having reached or exceeded on that date the corresponding 

number of FC as specified in Table 3 of this AD, replace the THSA with

a serviceable unit in accordance with the instructions of Airbus SB

A330-27-3199, or SB A340-27-4190, as applicable to aeroplane type and 

model.

Table 3 – THSA Removal for NBB Disks Replacement

Date

THSA FC Limit (since first installation on 

an aeroplane, or since last NBB

replacement, whichever is later)

31 July 2014 20 000 FC

31 January 2016 16 000 FC

31 July 2017 14 000 FC

31 July 2018 12 000 FC

Part B – For A340-500/-600 aeroplanes

(3) Not later than the date specified in Table 4 of this AD, as applicable,

for THSA having reached or exceeded on that date the corresponding 

number of FC specified in Table 4 of this AD, replace the THSA with a 

serviceable unit in accordance with the instructions of Airbus SB

A340-27-5062.

Table 4 – THSA Removal for NBB Disks Replacement

Date

THSA FC Limit (since first installation on 

an aeroplane, or since last NBB

replacement, whichever is later)

31 October 2015 6 000 FC

30 April 2017 5 200 FC

30 April 2018 4 400 FC

30 April 2019 3 500 FC
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Part C – For all aeroplanes affected by this AD

(4) From the date as specified in Table 3 or Table 4 of this AD, as applicable to 

aeroplane type and model, and before exceeding the FC limit corresponding 

to each date, as applicable, replace each affected THSA with a serviceable 

unit (see also paragraph (5) of this AD) in accordance with the instructions of 

Airbus SB A330-27-3199, or SB A340-27-4190, or SB A340-27-5062, as 

applicable to aeroplane type and model.

Conditions for the installation of an affected THSA on an aeroplane:

(5) From each date specified in Table 3 or Table 4 of this AD, as applicable, it is 

allowed to install a THSA on an aeroplane, provided the unit has not 

exceeded the corresponding number of FC specified in Table 3 or Table 4 of 

this AD, as applicable to aeroplane type/model.

Ref. Publications: Airbus SB A330-27-3199 dated 15 July 2014.

Airbus SB A340-27-4190 dated 15 July 2014.

Airbus SB A340-27-5062 dated 15 July 2014.

The use of later approved revisions of these documents 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. The original issue of this AD was posted on 25 July 2014 as PAD 14-121 and 

republished as PAD 14-121R1 on 06 November 2014 for consultation until 

20 November 2014. The Comment Response Document can be found at 

http://ad.easa.europa.eu/.

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 in this 

AD, please contact: AIRBUS – Airworthiness Office – EIAL;

E-mail: airworthiness.A330-A340@airbus.com.