CUSTOMER SERVICES DIRECTORATE

1 ROND POINT MAURICE BELLONTE

31707 BLAGNAC CEDEX FRANCE

TELEPHONE + 33 (0)5 61 93 33 33

ALERT OPERATORS TRANSMISSION - AOT

AOT ref: A28W002-13 Page 1 of 3 Date: 23 JUL 2013

SUBJECT: ATA 28 – Issue with electrical fuel pumps thermal fuses

AIRCRAFT TYPE: A300, A300-600, A300-600ST, A310

OUR REF.: A28W002-13 dated 23 July 2013.

1. AIRCRAFT AFFECTED

ALL A300, A300-600, A300-600ST, A310.

2. REFERENCES

Ref 1 - Maintenance Planning Document 240000-04-1

Ref 2 - Maintenance Planning Document 240000-0503-2

Ref 3 - Aircraft Maintenance Manual task 24-00-00 PB 601

Ref 4 - Aircraft Maintenance Manual task 28-21-00 PB001

Ref 5 - Aircraft Maintenance Manual task 28-27-00 PB001

Ref 6 - Electrical Standard Practices Manual 20-46-10

3. REASON

3.1 FACTS

One operator reported to Airbus the failure of two Zodiac fuel pumps P/N 2052C23 at the RH inner 

position on the same aircraft. After the second pump failure, the issue was solved by replacement of this 

pump (FIN 44QA), its associated CB (2QA) and AC essential bus load relay (14XH).

Testing was performed in order to replicate the issue and highlighted that, in case of loss of one phase 

on the pump supply and the associated circuit breaker failing to trip, the fuel pump thermal fuses may 

not operate as quickly as expected.

3.2 CONSEQUENCES

Based on these findings, further testing was conducted and demonstrated that, under a combination of 

conditions, the thermal fuses of the pump may not operate before the temperature of the pumps reaches 

more than 200°C.

This issue is applicable to all Zodiac fuel pumps P/N 2052C**.

3.3 AIM

The aim of this AOT is to mitigate the risk of possible fuel pump overheat by performing a more frequent 

operational check of the pumps circuit breakers to ensure that the associated CB will operate when 

required, including in the event of a loss of phase.
ALERT OPERATORS TRANSMISSION - AOT

AOT ref: A28W002-13 Page 2 of 3 Date: 23 JUL 2013

4. SHORT TERM ACTION

4.1 PLANNING AND MANPOWER

4.1.1 ACCOMPLISHMENT TIMESCALE

To date, all circuit breakers are advised to be checked as per MPD ref. 1 for A300-600, A310 and ref. 2

for A300 every 36 months.

This AOT requires a check of the inner, outer, centre and trim tank (where fitted) fuel pump circuit 

breakers every 500 FH or 6 months, whichever occurs soonest.

NOTE: this AOT is not applicable to the APU and ACT fuel pump CBs.

4.1.2 MANPOWER

The estimated time to perform the check of the fuel pumps CBs is 0.25 man-hour.

4.2 DESCRIPTION

Perform the opening and closing of the applicable fuel pump power supply CBs as per ref. 3.

The table below provides the list of applicable CBs.

A300B2 A300B4 A300-

600

A300-

600R

A300-

600ST

A310-

200

A310-

300

LH inner 

pump 2 1QA X X X X X X X

RH inner 

pump 1 2QA X X X X X X X

LH outer 

pump 2 3QA X X X X X X X

RH outer 

pump 1 4QA X X X X X X X

LH outer 

pump 1 5QA X X X X X X X

RH outer 

pump 2 6QA X X X X X X X

LH inner 

pump 1 7QA X X X X X X X

RH inner 

pump 2 8QA X X X X X X X

LH centre 

pump

99QA X X X X X X

RH centre 

pump

100QA X X X X X X

Trim 

pump 1 1QN X X

Trim 

pump 2 2QN X X

NOTE: “X” indicates that the CB is to be checked
ALERT OPERATORS TRANSMISSION - AOT

AOT ref: A28W002-13 Page 3 of 3 Date: 23 JUL 2013

For CB location, refer to AMM Ref 4, Ref 5.

4.3 FINDINGS

In case a CB is found failed or stuck closed, then replace this CB as per ref.6.

5. FOLLOW-UP PLAN

A modification of the fuel pump design is being developed in conjunction with Zodiac. It is anticipated 

that a replacement of the fuel pumps P/N 2052C** with the new pumps will cancel the requirement of 

the reduced interval check of the CB’s operation.

6. AOT APPROVAL

The technical content of this document is approved under the authority of DOA nr. EASA.21J.031.

7. REPORTING / ACKNOWLEDGEMENT

Operators are requested to acknowledge receipt of this AOT within 48 hours.

Questions about this AOT and inspection results with or without findings are to be sent to Airbus 

Customer Services engineering as soon as possible, after the AOT application, to the attention of:

Géraldine VALLEE

Fuel Systems Customer Support Engineer

SEEE5

CUSTOMER SERVICES

Phone: +33(0)5 62 11 87 43

Fax: +33(0)5 61 93 36 14

Mailto: geraldine.vallee@airbus.com

Best Regards,

Jean-Luc MOUYSSET

VICE PRESIDENT ENGINEERING SUPPORT

CUSTOMER SERVICES

Gilles DESESQUELLES

VICE PRESIDENT WIDEBODY PROGRAMME

CUSTOMER SERVICES