ALERT OPERATORS TRANSMISSION - ALERT OPERATORS TRANSMISSION

SUBJECT: ATA 71 - A330 CF6-80E1 Upper aft mount bolt inspection

OUR REF.: A71L002-13 dated 08 Apr 2013.

1. AIRCRAFT AFFECTED

All A330 powered with GE CF6-80E1.

2. REFERENCED DOCUMENTATION

2.1 APPENDIX

Appendix 1: Airbus Technical report Reference G54RP1310441 - GE CF6-80E1 - ATA 54-

51-18 Fractured Bolts on Aft Engine Mount Upper Beam.

2.2 REFERENCES

A330 GE IPC 71-22-41 Item 20 BOLT-DBL HEX HD.

A330 GE AMM 24-42-00-861-801-A Energize the Ground Service Network.

A330 GE AMM 78-31-00-040-802 Deactivation of the Thrust Reverser System for 

Maintenance.

A330 GE AMM Figure 05-24-50-991-03100-06-A / SHEET 1 - Access Doors/ Panels, 

Engine 1 Pylon.

A330 GE AMM Figure 05-24-50-991-03200-06-A / SHEET 1 - Access Doors/ Panels, 

Engine 2 Pylon.

A330 GE AMM 78-31-00-440-802-A Reactivation of the Thrust Reverser System after 

Maintenance.

A330 GE AMM 24-42-00-862-801-A De-energize the Ground Service Network.

3. REASON

3.1 FACTS

During the scheduled replacement of a CF6-80E1 engine#1 on an A330 aircraft, one bolt partnumber 1672M36P01 (IPC 71-22-41 Item 20 BOLT-DBL HEX HD) on the aft engine mount 

upper beam was found totally broken.

The bolt reportedly "fell down" upon removal of the lower beam.

The bolt in question is one of the four bolts that attach the upper beam to the pylon.

This was the original engine on the aircraft and had no removal since entry into service.
Since EIS, amongst numerous scheduled or unscheduled CF6-80E1 engine removals this is

the only case reported.

Extensive investigation on the fractured bolt and the upper beam revealed:

- A fatigue origin area with crack propagation from the boundary of the bolt.

- Visual examination of the bolt reveals spiral groove with cold work and microstructural 

distortion underlying that extended axially along the shank. The crack initiated at the edge of 

the groove.

- Once initiated, the complete fracture of the bolt was reached very quickly (quick 

propagation).

- The upper beam revealed a score mark on counter-bore edge.

To be noted that the 3 other bolts were found in good condition.

Preliminary root-cause understanding is that unusual contact with the counter-bore edge of the 

beam induced a very significant groove on the bolt during its installation, which eventually 

led to the bolt fracture.

As the root-cause is still under investigation, including the installation sequence specific to 

this aircraft - engine model, the AOT is not applicable for other A330 propulsion systems. 

3.2 CONSEQUENCES

Failure of one pylon-upper beam bolt is a failsafe case taken into account in certification 

analysis. During this abnormal flight condition the structure is designed to continue to sustain 

residual fatigue loads and limit loads during a minimum of one inspection interval (9,500 FC) 

as required per ALI task 545111-02-01. 

Furthermore, the engine mount structure is not designed to sustain the residual fatigue and 

limit loads on 2 bolts or less.

3.3 AIM

The aim of this AOT is to ask operators to perform a onetime ultrasonic inspection of the four 

aft mount-pylon bolts of each engine. That makes a total of eight aft mount pylon bolts 

inspected by aircraft. This will allow detection of cracks completely sheared through the bolt 

section. 

4. SHORT TERM ACTION

4.1 PLANNING AND MANPOWER

4.1.1 ACCOMPLISHMENT TIMESCALE

Airbus requires that the inspection as per procedure described in paragraph 4.2, is carried out 

at first opportunity and no later than 1000FH after receipt of this "Alert Operators 

Transmission".
4.1.2 MANPOWER

The estimated time to get access and perform the inspection is 2.5MH per engine.

The estimated time to apply the corrective actions in case of findings is 25Mh per engine. 

4.2 DESCRIPTION

4.2.1 ACCESS

Make sure that the safety devices and the warning notices are in position before you start a 

task on or near:

- The flight control.

- The flight control surfaces.

- The landing gear and the related doors.

- Components that move.

Movement of components can kill or injure persons.

Energize the ground service network as per AMM TASK 24-42-00-861-801.

Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do the 

inspection.

Put a WARNING NOTICE(S) to tell persons not to start the engines.

Get Access to the Avionics Compartment:

- Put an ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position at access door 811

- Open access door 811.

- Open the protective door of the AC/DC emergency power-center 740VU.

Open, safety and tag these circuit breakers:

- For FIN 4030EM1 (DEMOUNTABLE POWER PLANT, ENG1):

 o Panel: 722VU / Designation: FADEC B ENG 1 / FIN: 13KS1 / Location: D44

 o Panel: 742VU / Designation: FADEC A ENG 1 / FIN: 12KS1 / Location: Q73

- FOR FIN 4030EM2 (DEMOUNTABLE POWER PLANT, ENG2)

 o Panel: 722VU / Designation: FADEC B ENG 2 / FIN: 13KS2 / Location: K49

 o Panel: 742VU / Designation: FADEC A ENG 2 / FIN: 12KS2 / Location: Q74

Make the thrust reverser unserviceable as per AMM TASK 78-31-00-040-802.

Put an ACCESS PLATFORM 5M (16 FT) - ADJUSTABLE in position at the pylon leading 

edge (zones 453, 463).

Remove the access panels:

- For pylon 1: 453BL and 453BR 

- For pylon 2: 463BL and 463BR 
(Refer to AMM Figure 05-24-50-991-03100-06-A / SHEET 1 and - Figure 05-24-50-991-

03200-06-A / SHEET 1 for the locations of the Access Doors/ Panels, respectively on Engine 

1 Pylon and Engine 2 Pylon).

Perform the inspection as per paragraph 4.2.2 and contact Airbus in case of findings as per 

paragraph 4.2.3.

Make the thrust reverser serviceable as per AMM TASK 78-31-00-440-802

Remove the safety clips and the tags and close these circuit breakers:

- For FIN 4030EM1 (DEMOUNTABLE POWER PLANT, ENG1):

 o Panel: 722VU / Designation: FADEC B ENG 1 / FIN: 13KS1 / Location: D44

 o Panel: 742VU / Designation: FADEC A ENG 1 / FIN: 12KS1 / Location: Q73

- FOR FIN 4030EM2 (DEMOUNTABLE POWER PLANT, ENG2)

 o Panel: 722VU / Designation: FADEC B ENG 2 / FIN: 13KS2 / Location: K49

 o Panel: 742VU / Designation: FADEC A ENG 2 / FIN: 12KS2 / Location: Q74

Make sure that the work area is clean and clear of tools and other items

Install the access panels:

- For pylon 1: 453BL and 453BR 

- For pylon 2: 463BL and 463BR 

(Refer to AMM Figure 05-24-50-991-03100-06-A / SHEET 1 and - Figure 05-24-50-991-

03200-06-A / SHEET 1 for the locations of the Access Doors/ Panels, respectively on Engine 

1 Pylon and Engine 2 Pylon).

Close the protective door of the AC/DC emergency power-center 740VU.

Remove the WARNING NOTICE(S) in the cockpit.

Close access door 811.

Remove the access platform(s).

Remove the ground support and maintenance equipment, the special and standard tools and 

all other items.

De-energize the ground service network as per AMM TASK 24-42-00-862-801

4.2.2 INSPECTION REQUIREMENTS

Perform a onetime ultrasonic inspection of the four aft mount-pylon bolts of each engine.

Please refer to Appendix 1 to be provided with all the inspection instructions and tooling 

requirements for application of this AOT.

4.2.3 FINDINGS
In case of a fractured bolt is identified, before next flight contact Airbus since specific 

instructions would be provided with regards to components removal / installation.

Findings of a fracture bolt shall require the following actions:

- Removal of the engine.

- Removal of the aft mount hardware for shop inspection and potential repair.

5. FURTHER INFORMATION

5.1 FOLLOW-UP PLAN

Further actions may be considered based upon results of the ongoing investigations.

5.2 IMPACTED DOCUMENTATION

N/A

6. AOT APPROVAL

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

EASA.21J.031.

7. REPORTING

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

Emilie GAILLANOU, SEEE

E-mail: emilie.gaillanou@airbus.com

Fax number +33 (0)5 61 39 36 14

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:

Marie LALO

Repair & System Nacelles

Customer Engineering Support - SEEE6

CUSTOMER SERVICES

Phone: +33 (0)5 62 11 83 03 

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

mailto: marie.lalo@airbus.com 
Best Regards,

Jean-Luc MOUYSSET Philippe GOURDON

VICE PRESIDENT ENGINEERING SUPPORT VICE PRESIDENT A330/A340 

PROGRAMME

CUSTOMER SERVICES CUSTOMER SERVICES