EASA AD No.: 2015-0080

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EASA AIRWORTHINESS DIRECTIVE

AD No.: 2015-0080

Date: 07 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):

A318, A319, A320 and A321 aeroplanes

TCDS Number: EASA.A.064

Foreign AD: Not applicable

Supersedure: None

ATA 27 Flight Controls – Trimmable Horizontal Stabilizer Actuator –

Identification / Replacement

Manufacturer(s): Airbus (formerly Airbus Industrie)

Applicability: Airbus A318-111, A318-112, A318-121, A318-122, A319-111, A319-112,

A319-113, A319-114, A319-115, A319-131, A319-132, A319-133, A320-211, 

A320-212, A320-214, A320-215, A320-216, A320-231, A320-232, A320-233, 

A321-111, A321-112, A321-131, A321-211, A321-212, A321-213, A321-231 

and A321-232 aeroplanes, all manufacturer serial numbers.

Reason: During endurance qualification tests on A380 Trimmable Horizontal Stabilizer 

Actuator (THSA), a partial loss of the no-back brake (NBB) efficiency was 

experienced. Investigation results concluded that this particular malfunction 

was due to an ageing/endurance issue of the surfaces of the NBB carbon 

friction disks, leading to a partial loss of braking efficiency in some specific 

aerodynamic load conditions.

Due to design similarity on A320 family fleet, the same tests were initiated by 

the THSA manufacturer on certain SA type THSA, sampled from the field. 

Subject tests confirmed that THSA Part Number (P/N) 47145 series, as 

installed on A320 family aeroplanes, are also affected by this partial loss of 

NBB efficiency.

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 an uncommanded movement of the THS, possibly resulting in loss of 

control of the aeroplane.

For the reasons described above, this AD requires the removal from service of 

each affected THSA, with the intent of in-shop NBB carbon disk replacement.

Effective Date: 21 May 2015
EASA AD No.: 2015-0080

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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 only those 

identified by P/N 47145-XXX (XXX in the P/N stands for any numerical value).

Note 2: For the purpose of this AD, a serviceable THSA is a unit which has not 

exceeded the flight cycle (FC) limits specified in Table 1 of this AD, since first 

installation of the THSA on an aeroplane, or since last NBB replacement, 

whichever is later. NBB disc replacement can be accomplished through UTC 

Aerospace Systems (UTAS) Service Bulletin (SB) 47145-27-17.

(1) Not later than the date specified in Table 1 of this AD, as applicable, 

determine the FC accumulated by each affected THSA since first 

installation on an aeroplane, or since last NBB replacement (see Note 3 of 

this AD), whichever is later, and, for those having reached or exceeded on 

that date the corresponding number of FC specified in Table 1 of this AD,

replace the THSA with a serviceable unit (see Note 2 of this AD) in 

accordance with the instructions of Airbus SB A320-27-1242.

Note 3: In case no maintenance records concerning last NBB disk replacement 

are available, the FC accumulated since first installation of the THSA on an 

aeroplane apply.

(2) From each date as specified in Table 1 of this AD, and before exceeding 

the FC limit corresponding to each date, as applicable, replace each THSA 

with a serviceable unit (see Note 2 of this AD) in accordance with the 

instructions of Airbus SB A320-27-1242.

Table 1 – 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 December 2015 40 000 FC

31 December 2016 36 000 FC

31 December 2017 33 600 FC

31 December 2018 31 600 FC

31 December 2019 30 000 FC

Conditions for the installation of a THSA on an aeroplane:

(3) From each date specified in Table 1 of this AD, as applicable, it is allowed 

to install a THSA P/N 47145-XXX on an aeroplane, provided the unit is a

serviceable unit, as defined in Note 2 of this AD.

Ref. Publications: Airbus SB A320-27-1242 original issue dated 09 February 2015.

UTAS SB 47145-27-17 original issue dated 16 February 2015.

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. This AD was posted on 27 March 2015 as PAD 15-028 for consultation until 

24 April 2015. 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 – EIAS,

Fax +33 5 61 93 44 51, E-mail: account.airworth-eas@airbus.com.