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: A71N010-15 Rev 00 Page 1 of 4 Date: 30-SEP-2015

© AIRBUS S.A.S. 2015. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT

SUBJECT: ATA 71 – CFM56-5A - FWD ENGINE MOUNT BOLTS - TORQUE CHECK

AIRCRAFT TYPE: A319,A320

OUR REF.: A71N010-15 Rev 00 dated 30-SEP-2015.

1. AIRCRAFT AFFECTED

Applicable to A319 & A320 powered with CFM56-5A engines which have performed AMM task 71-00-

00-400-040-A01 “Installation of the power plant with the engine positioner TWW 75E” between May

2013 and August 2015.

2. REFERENCED DOCUMENTATION

AMM task 71-00-00-400-040-A01

AMM task 71-13-00-010-040-A

AMM task 78-36-00-010-040-A

AMM task 78-30-00-481-041-A

AMM task 78-36-00-410-040-A

AMM task 78-30-00-081-041-A

AMM task 71-13-00-410-040

IPC Chapter 71-21-11-01

IPC Chapter 71-21-11-01A

CMM task 71-21-06

3. REASON

Wrong units for Fwd Engine Mount bolt torque were introduced in the May 2013 revision of the AMM, in

task 71-00-00-400-040-A01 “Installation of the power plant with the engine positioner TWW 75E”.

3.1 FACTS

During maintenance, an operator reported to Airbus inconsistent Fwd Engine Mount torque units within

AMM instructions.

This error has the following impact:

- CFM56-5A

- AMM task 71-00-00-400-040-A01 “Installation of the power plant with the engine positioner

TWW 75E”

To torque the forward bolt using the tool adaptor PN 98D71203002206, the torque value was given in

“lbf.in” instead of “lbf.ft”.

3.2 CONSEQUENCES

This condition, if not corrected, could cause severe damage to the pylon bolts and adjacent structures,

leading to potential failure. Besides, if combined with any maintenance damage, it could lead to fwd

engine mount failure, possibly resulting in engine detachment.
ALERT OPERATORS TRANSMISSION - AOT

AOT ref: A71N010-15 Rev 00 Page 2 of 4 Date: 30-SEP-2015

© AIRBUS S.A.S. 2015. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT

3.3 AIM

The aim of this AOT is to provide operators with the instructions to perform a one-time torque check of

the FWD engine mount bolts and subsequent replacement and inspection at next engine removal.

This AOT applies to aircraft within the effectivity defined in paragraph 1 of this AOT.

4. SHORT TERM ACTION

4.1 PLANNING AND MANPOWER

4.1.1 ACCOMPLISHMENT TIMESCALE

Airbus requires that the inspections, as per procedure described in paragraph 4.2, are carried out at first

opportunity and no later than 3 months after receipt of this “Alert Operators Transmission”.

4.1.2 MANPOWER

The estimated time to perform the inspection is 2.5 man-hours (MH) per engine:

- Get and close access: 2 MH

- Check torque of fwd bolts: 0.5 MH

The estimated time to perform the corrective action(s) in case of findings is:

- Torqueing of an under-torqued bolt (get and close access time not included): 0,5 MH

o Replacement of all fwd engine mount bolts, nuts and washers (all bolts at once): N/A

(because it is done at engine removal)

4.2 DESCRIPTION

The requirements of this AOT consist in checking the Fwd Engine Mount bolts torque values, and retorque if necessary.

4.2.1 ACCESS

Open the fan cowl doors as per AMM Task 71-13-00-010-040-A.

Make the thrust reverser unserviceable as per AMM task 78-30-00-481-041-A.

Open the thrust reverser doors as per AMM task 78-36-00-010-040-A.

Perform the inspection as per paragraph 4.2.2 and replace if necessary as per paragraph 4.2.3.

Close the thrust reverser doors as per AMM task 78-36-00-410-040-A.

Make the thrust reverser serviceable as per AMM task 78-30-00-081-041-A.

Close the fan cowl doors as per AMM task 71-13-00-410-040-A.

4.2.2 INSPECTION REQUIREMENTS

Mark all four pylon bolts heads and adjacent areas to provide a reference point to indicate if the bolt

moves.
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AOT ref: A71N010-15 Rev 00 Page 3 of 4 Date: 30-SEP-2015

© AIRBUS S.A.S. 2015. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT

Apply a torque of 320 lbf.ft (43.39 m.daN) in a clockwise direction (tightening direction) to all four

forward engine mount pylon bolts, to check for an under-torque condition.

 If using tool adaptor P/N 98D71203002206 with the angle of 22.5 degrees: set the torque wrench

to 301 lbf.ft (40.81 m.daN) to get the required TORQUE.

 If using tool adaptor P/N 98D71203002206 with the angle of 67.5 degrees: set the torque wrench

to 307 lbf.ft (41.62 m.daN) to get the required TORQUE.

4.2.3 FINDINGS

4.2.3.1 Instructions

Check the marking applied in para 4.2.2 to confirm if the bolt has moved.

- If one or more bolt rotates:

o Before next flight:

o Re-torque twice the affected bolt(s) between 320 and 350 lbf.ft (43.39 and 47.45 m.daN)

 If using tool adaptor P/N 98D71203002206 with the angle of 22.5 degrees: set

the torque wrench to between 301 and 329 lbf.ft (40.81 and 44.60 m.daN) to get

the required TORQUE.

 If using tool adaptor P/N 98D71203002206 with the angle of 67.5 degrees: set

the torque wrench to between 307 and 336 lbf.ft (41.62 and 45.55 m.daN) to get

the required TORQUE.

o At next engine removal:

o Discard and replace the 4 bolts, nuts and washers by new ones, and proceed to inspection

check. Refer to paragraph 4.2.3.2 for procedure details.

NOTE: Inspection outcome with or without findings has to be sent to Airbus Customer Services

Engineering.

4.2.3.2 Procedure Details

Bolt replacement off-wing and inspection to carry out:

- Proceed to engine removal as per AMM Task 71-00-00 PB401.

- Remove the 4 pylon bolts and associated nuts and washers, and replace them by new ones.

- Perform Fluorescent Penetrant Inspection and dimensional check on impacted forward engine

mount platform pylon bolt holes when engine is removed. Refer to CFM56-5A CMM 71-21-06

instructions.

o If nil finding, forward engine mount platform can be reinstalled.

o If local deformation or cracks are found during the check, replace the forward platform

before next flight.

- Install the engine as per AMM Task 71-00-00 PB401.

4.3 SPARES AND TOOLING

A320 CFM56-5A IPC 71-21-11-01/-01A item 250 Bolt 83769H14-17

A320 CFM56-5A IPC 71-21-11-01/-01A item 260 Washer VN936NP14C

A320 CFM56-5A IPC 71-21-11-01/-01A item 270 Nut VN401B144
ALERT OPERATORS TRANSMISSION - AOT

AOT ref: A71N010-15 Rev 00 Page 4 of 4 Date: 30-SEP-2015

© AIRBUS S.A.S. 2015. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT

5. FURTHER INFORMATION

5.1 FOLLOW-UP PLAN

No further action is expected following AOT completion.

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

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

Customer Services through TechRequest on Airbus World, selecting Engineering Domain and ATA

71-21 / Topic AOT A71N010-15 Rev 00.

Best Regards,

Jean-Luc MOUYSSET

VICE PRESIDENT ENGINEERING SUPPORT

CUSTOMER SERVICES

Gilles DE CEVINS

VICE PRESIDENT A320 PROGRAMME

CUSTOMER SERVICES