**CUSTOMER SERVICES DIRECTO RATE** 

**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. REFERENC ES

Ref 1

- M aintenance P lanning D ocument 240000

- 04

- 1

Ref 2

- M aintenance P lanning D ocument 240000

- 0503

- 2

Ref 3

- A ircraft M aintenance M anual task 24

- 00

- 00 PB 601

Ref 4

- A ircraft M aintenance M anual task 28

- 21

- 00 PB001

Ref 5

- A ircraft M aintenance M anual 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 inn er

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).

T esting 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 operat e as quickly as expected

.

3.2 CONSEQUENCES

Based on these findings

, further testing was conduct ed 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 breaker s 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 require s 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 rece ipt 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