ALERT OPERATORS TRANSMISSION - ALERT OPERATORS TRANSMISSION

SUBJECT: ATA 27 - Wing Tip Brake (WTB) loss of braking function

OUR REF.: A27L001-12 rev 01 dated 27 April 2012.

OUR PREVIOUS REF.: A27L001-12 dated 26 April 2012.

0. REASON FOR REVISION

1) This revision has been sent to an enlarged distribution list as the first issue did not reach all 

affected operators;

2) Chapter 7 has been modified to add acknowledgement instruction.

The revised paragraphs are indicated by: **BEG.REV** and **END.REV**.

1. AIRCRAFT AFFECTED

All A330-200/-200F/-300 and A340-200/-300/-500/-600 in-service aircraft fitted with Wing 

Tip Brake (WTB) PN 1007A0000-03, PN 1007A0000-04 or PN 1007A0000-05.

2. REFERENCED DOCUMENTATION

2.1 Appendix

Appendix A: Reporting Sheet reference RS-SEEL6-2012-735701

2.2 References

- Ref.1: Operator Information Telex (OIT) SE 999.0106/10 - "ATA 27 - Wing Tip Brakes -

Loss Of Braking Function"

- Ref.2: All Operator Telex (AOT) A330-27A3174/A340-27A4172 - "ATA 27 - Wing Tip 

Brakes - Anticipated Check Of WTB/POB Braking Performance"

- Ref.3: Technical Follow-Up (TFU) 27.50.00.010 - "Wing Tip Brake - Loss of Braking 

Function"

- Ref.4. Aircraft Maintenance Manual (AMM) task 27-51-00-710-801 - "Flap - Operational 

Test of the Wing Tip Brake/Pressure-Off-Brake (POB)"

- Ref.5: AMM task 27-81-00-710-801 - "Slat - Operational Test of the WTB/POB"

- Ref.6: Maintenance Planning Document (MPD) revision April 01/2012 Task 275400-14-1 -

"Operational Check of Flap WTB/POB performance" / Maintenance Review Board Report 

(MRBR) task 27.50.00/14
- Ref.7: MPD revision April 01/2012 Task 278000-10-1 - "Operational Check of Slat 

WTB/POB performance" / MRBR task 27.80.00/10

- Ref.8: Airbus Service Bulletin (SB) A330-27-3183 / A340-27-4179 - "Flight Controls -

Replace Wing Tip Brake Standard A03 or A04 or A05 by Standard A06"

- Ref.9: AMM task 27-51-51 PB 401 - "Brake-Wing Tip-Removal/Installation"

- Ref.10: AMM task 27-81-51 PB 401 - "Brake-Wing Tip-Removal/Installation"

- Ref.11: Airbus SB A330-27-3189/A340-27-4184 - "Flight Controls - Replace Wing Tip 

Brake Standard A06 By Standard B01"

- Ref.12: Illustrated Parts Catalog (IPC) - figure 27-51-51/ figure 27-81-51 - "Brake - Wing 

Tip"

3. REASON

This AOT supersedes AOT Ref.2, which requested an anticipated one-time application of the 

operational test of Wing Tip Brake (WTB) Pressure-Off-Brake (POB) on the slat and flap 

systems. Due to the findings from Ref.2 AOT, the present AOT requests a repetitive 

application of that operational test at a shorter interval than Ref.6 & 7 in order to ensure a 

reliable operation of the flap and slat WTB until a reliable PN is installed at all four WTB 

positions.

3.1 FACTS

While performing the Ref.4 and Ref.5 tasks called by MPD/MRBR Ref.6 and Ref.7, an 

operator identified that the four WTB required replacement after failing the test. 

Strip examinations in shop confirmed that the four WTB had lost their braking capability due 

to brake plates being heavily worn out. 

The four affected WTB were PN 1007A0000-05. 

3.2 CONSEQUENCES

WTB are designed to stop and hold the mechanical transmission of slats and flaps in some 

specific failure cases. In such events, the Slat Flap Control Computers (SFCC) de-energize 

their WTB solenoids. This cuts the hydraulic pressure off, leading to brakes application.

Loss of the WTB braking function can result in the inability of the flap or slat system to be 

stopped and held in position, as required during operation in case of failure.

3.3 AIM

The aim of this AOT is to ensure a reliable operation of the flap and slat WTB by:

-Identifying potentially defective units.

-Performing repetitive tests Ref.4 & Ref.5 at every 1000FH until replacement of all WTB PN 

1007A0000-03, -04 or -05 by WTB PN 1007A0000-06 or 1007B0000-01.

-Replacing all WTB PN 1007A0000-03, -04 or -05 within 26 months from AOT receipt. 
3.4 INVESTIGATION

Analysis of the WTB returned from service has revealed that WTB fitted with brake plates 

supplied by Jurid (WTB PN 1007A0000-03, -04 or -05) are subject to premature wear. 

Note: WTB fitted with Miba brake plates (PN 1007A0000-06 or 1007B0000-01) have not 

shown similar signs of premature wear. This has been confirmed by a fleet sampling on hightime WTB PN 1007A0000-06 and 1007B0000-01.

This failure mode cannot be detected in normal operation, but can be detected during the 

Operational Test of the WTB/POB (AMM Ref.4 and Ref.5).

4. SHORT TERM ACTION

4.1 PLANNING AND MANPOWER

4.1.1 ACCOMPLISHMENT TIMESCALE

The following actions need to be performed, as per paragraph 4.2, on all affected aircraft:

- Within 30 days from receipt of this AOT, identify the aircraft equipped with WTB PN 

1007A0000-03, -04 or -05.

- Within 90 days from receipt of this AOT, report results of the identification to Airbus.

- Within 1000 FH since previous accomplishment of MPD/MRBR tasks ref.6 and ref.7 or 

since first flight of the aircraft, as applicable, or within 30 days from receipt of this AOT, 

whichever occurs later

 o Do the operational test of the slat and flap WTB/POB in accordance with AMM tasks ref. 

4 and ref. 5.

- Every 1000 FH, until replacement of all WTB PN 1007A0000-03, 1007A0000-04 and 

1007A0000-05, repeat the operational test of the slat and flap WTB/POB in accordance with 

AMM tasks Ref. 4 and Ref. 5.

- In case of findings:

 o Replace the failed WTB before further flight.

 o Report findings to Airbus within 90 days.

- Within 26 months from AOT receipt, replace all WTB PN 1007A0000-03, 1007A0000-04 

and 1007A0000-05.

4.1.2 MANPOWER

The estimated time to perform AMM Ref.4 and Ref.5 is:

- 2 man-hours 
- 1 hour elapsed time

with an additional 4 man-hours in case a WTB requires replacement.

4.2 DESCRIPTION

4.2.1 IDENTIFICATION OF AFFECTED AIRCRAFT

Within 30 days from receipt of this AOT:

a) Identify all aircraft fitted with at least one WTB PN 1007A0000-03, 1007A0000-04 or 

1007A0000-05.

The two following procedures are approved for the identification:

- Use the data from operators' approved records

- Read the data by visual inspection on aircraft

Within 90 days from receipt of this AOT:

b) Report each aircraft configuration to Airbus through the reporting sheet in Annex A.

4.2.2 REPETITIVE OPERATIONNAL TEST OF WTB/POB PERFORMANCE

On all affected aircraft, the following procedure shall be applied:

a) If only WTB PN 1007A0000-06 or 1007B0000-01 is installed on the aircraft (flap and slat 

systems), no further action is required by this AOT.

b) If at least one WTB PN 1007A0000-03, 1007A0000-04 or 1007A0000-05 is installed on 

the flap system (FIN 5060CV or 5138CV), within 1000 FH since previous accomplishment of 

MPD/MRBR task Ref.6 or since first flight of the aircraft, as applicable, or within 30 days 

from receipt of this AOT, whichever occurs later; and thereafter at intervals not to exceed 

1000 FH, do the Operational Test of the WTB/POB as per AMM Ref.4.

- If an operational test fails: 

 - BEFORE FURTHER FLIGHT, replace the faulty WTB by a serviceable WTB unit in 

accordance with instructions of i) or ii) as follows:

i) Installation of PN 1007A0000-06 or 1007B0000-01:

 o For pre-MOD 43512 aircraft, install WTB PN 1007A0000-06 as per SB Ref.8 or WTB 

PN 1007B0000-01 as per SB Ref.11.

 o For post-MOD 43512 aircraft, replace the WTB through AMM Ref.9 to recover the 

original aircraft delivery configuration. 

SB Ref.11 can be embodied to install WTB PN 1007B0000-01.

ii) Installation of PN 1007A0000-03 or PN 1007A0000-04 or PN 1007A0000-05 as per AMM 

Ref. 9 is authorized on pre-MOD 43512 aircraft provided that the replacement flap WTB is 

successfully tested on aircraft as per AMM Ref.4.

 - Report findings to Airbus within 90 days.
c) If at least one WTB PN 1007A0000-03, 1007A0000-04 or PN 1007A0000-05 is installed 

on the slat system (FIN 5120CW or 5060CW), within 1000 FH since previous 

accomplishment of MPD/MRBR task ref.7 or since first flight of the aircraft, as applicable, or 

within 30 days from receipt of this AOT, whichever occurs later; and thereafter at intervals 

not to exceed 1000 FH, do the Operational Test of the WTB/POB as per AMM Ref.5.

- If an operational test fails: 

- BEFORE FURTHER FLIGHT, replace the faulty WTB by a serviceable WTB unit in 

accordance with instructions of i) or ii) as follows:

i) Installation of PN 1007A0000-06 or 1007B0000-01:

 o For pre-MOD 43512 aircraft, install WTB PN 1007A0000-06 as per SB Ref.8 or WTB 

PN 1007B0000-01 as per SB Ref.11.

 o For post-MOD 43512 aircraft, replace the WTB through AMM Ref.10 to recover the 

original aircraft delivery configuration. 

SB Ref.11 can be embodied to install WTB PN 1007B0000-01.

ii) Installation of PN 1007A0000-03 or PN 1007A0000-04 or PN 1007A0000-05 as per AMM 

Ref.10 is authorized on pre-MOD 43512 aircraft provided that the replacement slat WTB is 

successfully tested on aircraft as per AMM Ref.5.

- Report the findings to Airbus within 90 days.

Note: A Serviceable WTB unit is defined as a part having:

- P/N 1007A0000-06 (preferred P/N) or

- P/N 1007B0000-01 (preferred P/N) or

- Only on pre-MOD 43512 aircraft, P/N 1007A0000-03 or P/N 1007A0000-04 or P/N 

1007A0000-05 which has been successfully tested on aircraft after its installation as per 

AMM Ref.4 or Ref.5 (P/N to be used exceptionally in case of spare shortage).

4.2.3 WTB REPLACEMENT

Within 26 months from receipt of this AOT:

Replace all remaining WTB PN 1007A0000-03, 1007A0000-04 or 1007A0000-05 by WTB

PN 1007A0000-06, depending on aircraft configuration:

- For pre-MOD 43512 aircraft, install WTB PN 1007A0000-06 as per SB Ref.8.

- For post-MOD 43512 aircraft, replace the WTB through AMM Ref.9 or AMM Ref.10 to 

recover the original aircraft delivery configuration.

Installation of a WTB PN 1007B0000-01 as per SB Ref.11 instead of a WTB PN 1007A0000-

06 is an acceptable means to comply with this AOT, as these units are 2-way interchangeable 

as per IPC Ref.12.

Once all WTB PN 1007A0000-03, 1007A0000-04 or 1007A0000-05 have been replaced on 

an aircraft by PN 1007A0000-06 or PN 1007B0000-01:
- The MPD/MRBR Ref.6 and Ref.7 interval is restored for the accomplishment of the 

Operational Test of the WTB/POB.

- No further action is required. 

4.3 SPARES AND TOOLING

No specific tooling is required to perform the actions described in this AOT.

Spare WTB units have been positioned in Singapore, Europe and the USA, in order to reduce 

delivery lead-time. Orders for spare WTB should be addressed to: 

GOODRICH AOG CONTACT:

Worldwide: tel. +44/121.451.5904

Fax +44/121.451.6133

E-mail: 24-7@goodrich.com

North America: tel. +1/800.735.7899

Due to the limited number of available spares, the following rules will apply for spares 

delivery:

a) For paragraph 4.2.2, spares will be delivered upon request when a WTB is confirmed faulty 

during the test,

b) For paragraph 4.2.3, Goodrich will organize a retrofit campaign of WTB PN 1007A0000-

03, -04 and -05, which Airbus will supervise. An Airbus Retrofit Information Letter (RIL) 

will cover this retrofit.

5. FOLLOW-UP PLAN

Follow-up of this AOT will be ensured by means of TFU Ref.3.

6. AOT APPROVAL

The technical content of this document is approved under the authority of DOA nr. 

EASA.21J.031.

It is anticipated that this AOT will be rendered mandatory by the Airworthiness Authorities.

7. REPORTING/ACKNOWLEDGEMENT

BEG REV*

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

BONNET Laétitia

E-mail:laetitia.bonnet@airbus.com

Fax number +33 (0)5 67 19 12 05

END REV*
Questions about this AOT and inspection results with or without findings shall be sent to 

Airbus Customer Services Engineering within 90 days after AOT application, to the attention 

of:

HERVAGAULT, Cédric, SEEL6

Phone: +33 (0)5 62 11 75 29

Fax number +33 (0)5 67 19 12 05

E-mail: cedric.hervagault@airbus.com

Best Regards,

Jean-Luc MOUYSSET Philippe GOURDON

VICE PRESIDENT ENGINEERING SUPPORT VICE PRESIDENT A330/A340 

PROGRAMME

CUSTOMER SERVICES CUSTOMER SERVICES