Ref No.: AOT

- CN235

- 76

- 0001
Rev No.: 0 Rev Date: 2 7 /05 /2014

SERVICES DIRECTORATE Po John Lennon s/n 28906 Getafe, Madrid, SPAIN MTA.TechnicalService@military.airbus.com 

# Alert Operators Transmission Page 1 / 4 ATA Chapter: 76 Subject: Engine control teleflex cable P/N 72830

- 20 fracture

Aircraft Type: CN

- 235

- 100/

- 100M/

- 200/

- 200M Applicability: MSN 031

- 120 (C016

– C073) Referenced Documents: Ref.1: COM 235

- 140 Ref.2: DGAC AD 03

- 00 Ref.3: FAA AD 2001

- 12

- 18. Ref.4: AMM 76

- 10

- 14

- 401



### 1. REASON FOR REVISION

This is the first issue of the AOT

.



### 2. REASON

Power and condition control levers are installed on a flight control quadrant on the cockpit center console. Movement of the levers is transmitted to the engines and propellers by a system of cables and pulleys which are installed along the inside of the fuselage and go out through pressure seals to the center ring front spar. P/N 7

- 44728

- 12 is the cable assembly located in cockpit area. P/N 72830

- 20 is the curved part of three parts of mentioned cable assembly. Figure 1 (contained in the Annex of this document) shows the P/N 7

- 44728

- 12 assembly and the subassembly P/N 72830

- 20 in red color

.
In year 1999 , a CN

- 235 Operator (under civil Type Certificate) reported the breakage of three engine control system cables P/N 7

- 44728

- 12 (AC710152) . Two of them corresponded to the Power Lever and the other one corresponded to the Condition Lever. Each of the cracks had occurred in dif ferent aircrafts and each cable had more than 14.000 FC. After the analysis of the affected cables, it was concluded that the breakage, which always happened in the same cable

area ( P/N 72830

- 20 ) , was caused by fatigue.

Airbus Military issued COM 235

- 140 and, subsequentl y, Spanish Airworthiness Authority DGAC issued AD 03

- 00 requesting the replacement of the affected assembly, P/N 7

- 44728

- 12, or the affected cable, P/N 72830

- 20, before they reach 12000 FC. One year later, in 2001, FAA issued AD 2001

- 12

- 18 with similar instructions.

In September 2010, another CN

- 235 operator (under military Type Certificate) informed AiM about the breakage of a CL control cable P/N 72830

- 20 after 8497 FH and 8858 aircraft FC. An analysis was requested to identify the root cause of the failure.

Airbus Military performed a fractographic analysis of the unit which determined fatigue nucleation seemed to have been facilitated by microcracks along the cable surface. A fractographic analysis was then performed on other no damaged cable with similar FH but no relevant surface defect was observed. Nevertheless , although the defect was only observed in failed cable, Triumph Controls was requested to take special care when p r ocessing the cables to maximize the surface quality of the cable

.Reference No.: AOT

- CN235

- 76

- 0001

Revision No.: 0 Date

: 2 7/0 5 /2014 

# Alert Operators Transmission Page 2 / 4 ATA Chapter: 76 Subject: Engine control teleflex cable fracture

2.1 FACTS

Recently, Airbus Military has been informed about the breakage of a PL control cable P/N 72830

- 20 in aircraft accumulating 9936 FH and 10552 FC, during ground operation. Root cause for this new event, after analyzing the results of the fra ctographic study, has been identified again as fatigue nucleation.

In the light of the events, and supported by test performed in collaboration with Triumph Controls and fatigue calculations, Airbus Military has determined a new cable life limit of 5000 aircraft flight cycles.

E ngine control system cables P/N 7

- 44728

- 12 (AC710152) configuration is only applicable for those CN

- 235 A/C between MSN 031 and MSN 120, both included.

2.2 CONSEQUENCES

The breakage of mentioned cable may cause the affected engine control loss; being necessary the affected engine shut down.

2.3 AIM

The aim of this AOT is to inform affected operator s about this new occurrence, as well as providing new cable life limit of 5000 FC. In service cables replacement intervals have been also identified to permit operators to proceed with a scheduled replacement program.



### 3. SHORT TERM ACTION

Airbus Military recommends the rep lacement of all power lever an d control lever Teleflex cables P/N 72830

- 20 before those cables exceed 5000 aircraft flight cycles, in accordance with AMM 76

- 10

- 14

- 401_Cfg.01 instructions (steps 3.A .1 to 3.A.4 ; 3.B.1; 3.B.7; 3.B.8; 3.B.11; 3.B.12; 3.B.13; 3

. C.1; 3. D.12; 3. D.13; 3. D.15 and 3.E

. 1 to 3.E .5 )

. For those cables currently installed with more than 5000 FC, the replacement must be done within the following timeframes:

Cable FC Timeframe

5000

- 6000 300 FC or 1 year, which occurs first 6000

- 7000 200 FC or 6 months, which occurs first > 7000 100 FC or 3 months, which occurs first

CAUTION: removed Teleflex cables must be discarded.Reference No.: AOT

- CN235

- 76

- 0001

Revision No.: 0 Date

: 2 7/0 5 /2014 

# Alert Operators Transmission Page 3 / 4 ATA Chapter: 76 Subject: Engine control teleflex cable fracture

NOTE: operators are responsible of P/N 72830

- 20 flight cycles monitoring in accordance with their respective approved maintenance and continued airworthiness procedures.



### 4. FURTHER INFORMATION

4.1 IMPACTED DOCUMENTATI ON

This AOT cancels the COM 235

- 140 (Ref.1). It will be also directed to the Airworthiness Authorities in order to review current AD’s instructions (Ref. 2 & 3).



### 5. REPORTING

Questions about this AOT and inspection results with or without findings are to be sent to Airbus Military Technical Assistance Center (AMTAC): Telephone: (+34) 91 600 79 99 E

- mail: MTA.TechnicalService@military.airbus.com

Released by

Yolanda Lara Martín

© EADS CASA. 2014

. All rights reserved. Confidential and proprietary document. This document and all information contained herein is the sole property of EADS CASA

. No intellectual property rights are granted by the delivery of this document or the disclosure of its content. This document shall not be reproduced or disclosed to a third party without the express written consent of EADS CASA

. This document and its content shall not be used for any purpose other than that for which it is supplied. ©EADS CASA 2014 All right reservedReference No.: AOT

- CN235

- 76

- 0001

Revision No.: 0 Date

: 2 7/0 5 /2014 

# Alert Operators Transmission Page 4 / 4 ATA Chapter: 76 Subject: Engine control teleflex cable fracture



### 6. ANNEX

Figure 1. Assembly P/N 7

- 44728

- 12.