AIRBUSA350

ID: 2017-0200
Issue date: 2017-10-10
Effective date: 2017-10-17  
Source: EASA
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Hydraulic System / Fuel Tank Inerting System – Engine Driven Pump Rapid Overheat – Master Minimum Equipment List Restriction / Software Update

EASA AD No.: 2017-0200


Airworthiness Directive
AD No.: 2017-0200
Issued: 10 October 2017
Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation
(EC) 216/2008 on behalf of the European Union, 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 Regulation (EU) 748/2012, Part 21.A.3B. In accordance with Regulation (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 [Regulation (EU) 1321/2014 Annex I,
Part M.A.303] or agreed with the Authority of the State of Registry [Regulation (EC) 216/2008, Article 14(4) exemption].


Design Approval Holder’s Name: Type/Model designation(s):
AIRBUS A350 aeroplanes

Effective Date:
17 October 2017
TCDS Number(s): EASA.A.151
Foreign AD: Not applicable
Supersedure: This AD supersedes EASA AD 2017-0180 dated 18 September 2017.



ATA 29, 47 – Hydraulic System / Fuel Tank Inerting System – Engine Driven Pump
Rapid Overheat – Master Minimum Equipment List Restriction / Software Update


Manufacturer(s):

Airbus

Applicability:

Airbus A350-941 aeroplanes, all serial numbers.

Reason:

In the Airbus A350 design, the hydraulic fluid cooling system is located in the fuel tanks. Recently,
an overheat failure mode of the hydraulic engine-driven pump (EDP) was found. Such EDP failure
may cause a fast temperature rise of the hydraulic fluid.

This condition, if not detected and corrected, combined with an inoperative fuel tank inerting
system, could lead to an uncontrolled overheat of the hydraulic fluid, possibly resulting in ignition of
the fuel-air mixture in the affected fuel tank.

To address this potential unsafe condition, Airbus issued a Major Event Revision (MER) of the A350
Master Minimum Equipment List (MMEL) that incorporates restrictions to avoid an uncontrolled
overheat of the hydraulic system. Consequently, EASA issued Emergency AD 2017-0154-E to require
implementation of these dispatch restrictions.


TE.CAP.00110-006 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified. Page 1 of 3
Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.
An agency of the European Union
EASA AD No.: 2017-0200

Since EASA Emergency AD 2017-0154-E was issued, following further investigation, Airbus issued
another MER of the A350 MMEL that expands the number of restricted MMEL items. At the same
time, Airbus revised Flight Operation Transmission (FOT) 999.0068/17, to inform all operators about
the latest MMEL restrictions. Consequently, EASA issued AD 2017-0180, retaining the requirements
of EASA Emergency AD 2017-0154-E, which was superseded, and requiring implementation of the
new Airbus A350 MMEL MER and, consequently, restrictions for aeroplane dispatch.

Since EASA AD 2017-0180 was issued, Airbus developed a software (SW) update of the Hydraulic
Monitoring and Control Application (HMCA), SW S4.2, introduction of which avoids uncontrolled
overheat of the hydraulic system. HMCA SW S4.2 is embodied in production through Airbus
modification (mod) 112090, and introduced in service through Airbus Service Bulletin (SB)
A350-29-P012.

For the reasons described above, this AD retains the requirements of EASA AD 2017-0180, which is
superseded, and requires modification of the aeroplane by installing HMCA SW S4.2.

This AD is still considered to be an interim action and further AD action may follow.

Required Action(s) and Compliance Time(s):

Required as indicated, unless accomplished previously:

Note 1: Group 1 aeroplanes are those that, on the effective date of this AD, do not have HMCA SW
S4.2 installed. Group 2 aeroplanes are post-mod 112090 and have HMCA SW S4.2 installed.

MMEL Changes - Dispatch Restrictions:
(1) Before next flight after 24 August 2017 [the effective date of EASA AD 2017-0154-E], implement
the MMEL changes in accordance with Airbus A350 MMEL MER dated 21 August 2017.

(2) Within 30 days after 22 September 2017 [the effective date of EASA AD 2017-0180], implement
the MMEL changes in accordance with Airbus A350 MMEL MER dated 06 September 2017,
inform all flight crews, and, thereafter, operate the aeroplane accordingly.

Modification:
(3) For Group 1 aeroplanes: Within 30 days after the effective date of this AD, modify the
aeroplane by installing HMCA SW S4.2 in accordance with the instructions of Airbus
SB A350-29-P012.

Part Installation:
(4) Do not install on any aeroplane an HMCA software pre-mod HMCA SW 4.2, as required by
paragraph (4.1) or (4.2) of this AD, as applicable.

(4.1) For Group 1 aeroplanes: After modification of the aeroplane as required by paragraph (3)
of this AD.

(4.2) For Group 2 aeroplanes: From the effective date of this AD.




TE.CAP.00110-006 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified. Page 2 of 3
Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.
An agency of the European Union
EASA AD No.: 2017-0200

(5) Installation of an HMCA SW standard approved after the effective date of this AD is equal to
compliance with the requirements of paragraph (3) of this AD, provided the conditions as
specified in paragraphs (5.1) and (5.2) of this AD are met.

(5.1) The HMCA SW standard must be approved by EASA, or approved under Airbus Design
Organisation Approval (DOA); and

(5.2) The installation must be accomplished in accordance with aeroplane modification
instructions approved by EASA, or approved under Airbus DOA.

Ref. Publications:

Airbus A350 MMEL MER dated 21 August 2017, EASA approval reference D17028232.

Airbus A350 MMEL MER dated 06 September 2017, EASA approval reference D17029962, which is
available at AirbusWorld.

Airbus Flight Operation Transmission 999.0068/17 Rev. 01, dated 06 September 2017.

Airbus A350 SB A350-29-P012 original issue, dated 06 October 2017.

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. 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 EASA Safety Information Section,
Certification Directorate. E-mail: ADs@easa.europa.eu.

4. For any question concerning the technical content of the requirements in this AD, please
contact: AIRBUS XWB, E-mail: continued-airworthiness.a350@airbus.com.




TE.CAP.00110-006 © European Aviation Safety Agency. All rights reserved. ISO9001 Certified. Page 3 of 3
Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.
An agency of the European Union

This is a partial extract of the full document - please refer to the actual report for full information.
Sources as credited.