EASA AD No.: 2014-0174

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EASA AIRWORTHINESS DIRECTIVE

AD No.: 2014-0174

Date: 23 July 2014

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 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 operate 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:

AIRBUS

Type/Model designation(s):

A318, A319, A320 and A321aeroplanes

TCDS Number: EASA.A.064

Foreign AD: Not Applicable

Supersedure: None

ATA 34 Navigation – Terrain Awareness Warning System – Power Cycle

(Reset)

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 (MSN).

Reason: Following two cases of spurious Terrain Ahead Warning System (TAWS) alert 

during approach and take off in Geneva, the concerned Transponder, Terrain 

and Traffic Collision Avoidance System (T3CAS) was sent to ACSS, the

manufacturer of the affected equipment, for investigation. The results of a 

laboratory investigation indicated that an internal frozen position anomaly

occurs when T3CAS is constantly powered for more than 149 hours. The origin 

for this defect was identified as a counter limitation, which is identified as a 

purely T3CAS software misbehaviour and is not self-detected. Only T3CAS 

units having Part Number (P/N) 9005000-10000 (software Standard 1.0), P/N 

9005000-10101 (Standard 1.1), and P/N 9005000-10202 (Standard 1.2) are 

affected by this software error.

This condition, if not corrected, could lead to spurious TAWS alerts which could 

increase flight crew workload during critical landing or take off phases, possibly 

resulting in reduced control of the aeroplane.

Prompted by these reports, Airbus issued Alert Operators Transmission (AOT) 

A34N004-13 to provide instructions to reset the T3CAS.

For the reasons described above, this AD requires repetitive on ground power 

cycles (resets) of the T3CAS unit.
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Effective Date: 06 August 2014

Required Action(s) 

and Compliance

Time(s):

Required as indicated, unless accomplished previously:

(1) For aeroplanes equipped with a T3CAS unit having a P/N listed in Table 1 

of this AD, within 30 days after the effective date of this AD, and,

thereafter, at intervals not to exceed 120 hours of continuous power of the 

T3CAS, accomplish an on ground power cycle on the T3CAS in 

accordance with the instructions of Airbus AOT A34N004-13. 

Table 1 – Affected T3CAS Units

P/N Software Standard

9005000-10000 1.0

9005000-10101 1.1

9005000-10202 1.2

(2) Within 12 months after the effective date of this AD, revise the approved 

aircraft maintenance programme (AMP) and standard practices, on the 

basis of which the operator or the owner ensures the continuing 

airworthiness of each operated aeroplane, by incorporating the T3CAS on 

ground power cycle instructions, as specified in Airbus AOT A34N004-13.

(3) Revising the AMP, as required by paragraph (2) of this AD, constitutes 

compliance with the requirements of paragraph (1) of this AD. After 

revising the AMP, as required by paragraph (2) of this AD, it is not 

necessary that accomplishment of each T3CAS on ground power cycle 

action is recorded for demonstration of AD compliance on a continued 

basis.

Note: For affected aeroplanes registered in Europe, complying with the 

approved AMP as specified in paragraph (2) of this AD is required by 

Commission Regulation (EC) No 2042/2003, Part M.A.301, paragraph 3.

(4) An aeroplane on which Airbus modification (mod) 39146, or mod 152980,

or mod 154341, has not been embodied in production, does not have to

comply with the requirements of paragraphs (1) and (2) of this AD,

provided it can be demonstrated that no T3CAS unit having a P/N listed in 

Table 1 of this AD is installed on that aeroplane.

(5) From the effective date of this AD, installation on an aeroplane of a T3CAS 

unit having a P/N and software standard as listed in Table 1 of this AD is 

acceptable, provided that, following installation, the T3CAS unit is power 

cycled on a recurrent basis, as required by this AD.

(6) Installation on an aeroplane of a version (P/N) of T3CAS approved after 

the effective date of this AD constitutes terminating action for the recurrent 

on ground power cycles as required by this AD for that aeroplane,

provided the conditions as specified in paragraphs (6.1) and (6.2) of this 

AD are met.

(6.1) The version (P/N) must be approved by EASA, or approved under 

Airbus DOA; and

(6.2) The installation must be accomplished in accordance with aeroplane 

modification instructions approved by EASA, or approved under 

Airbus DOA.

Ref. Publications: Airbus AOT A34N004-13 original issue, dated 25 November 2013, or

Revision 01 dated 19 March 2014.

The use of later approved revisions of this document is acceptable for 

compliance with the requirements of this AD.
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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, 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 AIRBUS – Airworthiness Office – EIAS;

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