40220 Tarnos - France 

Tel. +33 (0)5 59 74 40 00 - Telex 570 042 - Fax +33 (0)5 59 74 45 15

MANDATORY SERVICE BULLETIN 

ARRIEL 2 No. 292 72 2849

Subject: 41/23 tooth bevel gear assembly of the accessory gearbox 

(module M01). 

Application of TI No. 292 72 2849 or No. 292 72 2850 

referencing vibration check. 

The technical information contained in this document is approved 

under the Design Organization Approval No. EASA.21J.070.

Version: B 

Reason for update: Modification of the effectivity code. 

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MANDATORY SERVICE BULLETIN 

1. Compliance conditions 

CAUTION: FAILURE TO APPLY THIS MANDATORY SERVICE BULLETIN MAY LEAD TO AN 

UNCOMMANDED IN-FLIGHT ENGINE SHUT-DOWN WHICH, ON A SINGLE-ENGINE 

HELICOPTER, LEADS TO AN EMERGENCY AUTOROTATION LANDING. 

A. Mandatory Service Bulletin (SB) effectivity date 

Date on which this Mandatory SB becomes effective and must systematically be complied 

with, according to the conditions of application. 

This date corresponds to when all resources needed to perform the procedure (parts, tools, 

documentation, etc.) will be available. 

If these resources are available any earlier, the Mandatory SB may, as an exception, be 

applied prior to the effectivity date. 

NOVEMBER 2013 

B. Effectivity 

Application of this Mandatory SB is considered mandatory as a result of a technical 

requirement which might affect flight safety of engines in service. It may be done as defined 

by the effectivity code given in the table below. 

Note 1: This Mandatory SB does not apply if this version (version B) or its version A 

(recommended SB) is already indicated on module M01 log card. 

Note 2: This Mandatory SB does not apply if the the achievement of the 41 tooth gear 

vibration check is indicated on module M01 log card, refer to SL 2892/13/ 

ARRIEL2. 

Note 3: This Mandatory SB does not apply if the serial number of module M01 is shown in 

the list on Figure 01. 

2. Purpose 

CAUTION: FAILURE TO APPLY THIS MANDATORY SERVICE BULLETIN MAY LEAD TO AN 

UNCOMMANDED IN-FLIGHT ENGINE SHUT-DOWN WHICH, ON A SINGLE-ENGINE 

HELICOPTER, LEADS TO AN EMERGENCY AUTOROTATION LANDING. 

The purpose of this Mandatory SB is to check the meshing quality of 41/23 tooth bevel gear of 

accessory gearbox (module M01). 

3. Reason 

TURBOMECA has been informed of several uncommanded in-flight shutdown events following 

rupture of 41 tooth gear forming part of 41/23 tooth bevel gear of accessory gearbox (module 

M01). 

Investigation into these events revealed that the meshing quality of this bevel gear could be a 

contributing factor in the rupture. 

Effectivity Code * 

ARRIEL 2B - 2B1 - 2B1A - 2B1B 1-B 

* The actions and conditions of application are described in paragraph 5. 

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MANDATORY SERVICE BULLETIN 

4. Description 

This Mandatory SB consists of applying a Technical Instruction (TI) to check meshing vibration 

level of 41/23 tooth bevel gear of module M01. 

5. Required actions and compliance times 

A. At the operator's site 

Application before the 31st of October 2016. 

Apply TI X 292 72 2849 to check meshing vibration level of 41/23 tooth bevel gear of 

module M01 according to paragraph 6. 

Consider the vibration check results after receiving the measurement report: refer to 

paragraph 6.B.1. 

B. At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

Application before the 31st of October 2016. 

Apply TI X 292 72 2850 to check meshing vibration level of 41/23 tooth bevel gear of 

module M01 if task 71-02-15-760-801-A01 of the Maintenance Manual is applied: refer to 

paragraph 6. 

C. At a TURBOMECA-approved Repair Center 

Not applicable. 

6. Accomplishment Instructions

A. Implementation 

The application of this Mandatory SB does not necessitate removing the engine from the 

helicopter. 

(1) At the operator's site 

(a) Apply TI X 292 72 2849 to check meshing vibration level of 41/23 tooth bevel 

gear of module M01. 

(b) Identify module M01 status in the FMFE of module M01, refer to paragraph 6.D.1 

(c) Send an acknowledgement of receipt for the measurement report to your NORIA 

coordinator, refer to paragraph 7.C. 

(2) At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

If bench testing according to task 71-02-15-760-801-A01 of the Maintenance Manual: 

(a) Apply TI X 292 72 2850 to check meshing vibration level of 41/23 tooth bevel 

gear of module M01. 

(b) Identify module M01 status in the FMFE of module M01, refer to 

paragraph 6.D.2. 

(3) At a TURBOMECA-approved Repair Center 

Not applicable. 

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MANDATORY SERVICE BULLETIN 

B. Operating instructions 

(1) At the operator's site 

(a) Apply TI X 72 292 2849. 

(b) Actions according to the vibration check result specified in the email sent by 

Turbomeca or in the report generated by the B&K server: 

1 Level 1 - Green indicator: keep module M01 in service. 

2 Level 2 - Yellow indicator: remove module M01 within 150 hours or 3 months 

(first limit reached). 

3 Level 3 - Orange indicator: remove module M01 within 25 hours (or earlier, 

depending on the recommendations made by Turbomeca) or 3 months (first 

limit reached). 

4 If "measure invalid", contact your TURBOMECA representative. 

(c) Send an acknowledgement of receipt by email or fax to your NORIA coordinator, 

refer to paragraph 7.C, confirming that the status of module M01 has been taken 

into account. 

(2) At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

If maintenance task 71-02-15-760-801-A01 is applied; 

(a) Apply TI X 72 292 2850. 

(b) Actions according to the vibration check result: 

1 Compliant result: release module M01 into service. 

2 Non-compliant result: return module M01 to a Repair Center. 

(3) At a TURBOMECA-approved Repair Center 

Not applicable. 

C. Reconditioning and checks 

(1) At the operator's site 

Not applicable. 

(2) At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

Perform a ground run check: refer to ARRIEL 2 Maintenance Manual, task 71-02-13-

280-801. 

(3) At a TURBOMECA-approved Repair Center 

Not applicable. 

D. Identification 

(1) At the operator's site 

(a) Record the application of this Mandatory SB on the FMFE of the module M01 

indicating the measurement level as follows: “level 1 – green”, “level 2 – yellow” 

or “level 3 – orange”, as well as the module M01 TSN at the time of the 

measurement. 

(b) If necessary, notify TURBOMECA that standard exchange of module M01 has 

been performed by returning the fully completed compliance certificate 

(Appendix). 

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MANDATORY SERVICE BULLETIN 

(2) At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center

(a) If the vibration check result is compliant, record the application of this Mandatory 

SB on the module M01 log card. 

(b) If the vibration check result is not compliant, notify TURBOMECA that standard 

exchange of module M01 has been performed by returning the fully completed 

compliance certificate (Appendix). 

(3) At a TURBOMECA-approved Repair Center 

Not applicable. 

E. Routine maintenance 

No modification to the routine maintenance. 

7. Material information 

A. Basic information 

The parts list required for the application of this Mandatory SB is for one engine. 

B. List of parts 

(1) At the operator's site 

Refer to TI X 292 72 2849, to the Maintenance Manual and/or to the relevant ARRIEL 2 

Spare Parts Catalog. 

(2) At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

Refer to TI X 292 72 2850, to the relevant ARRIEL 2 Maintenance Manual and/or 

Spare Parts Catalog. 

(3) At a TURBOMECA-approved Repair Center 

Not applicable. 

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MANDATORY SERVICE BULLETIN 

C. Supply conditions 

Supply of parts will be managed by: 

For North and Central America 

TURBOMECA-Noria 

Team Dallas 

2709 Forum Drive 

Grand Prairie, TX 75052 – USA 

Fax : +1 972 606 76 68 

noria-dallas@turbomeca.com

Team Canada

11800, rue Helen-Bristol 

J7N 3G8 QC MIRABEL –Canada 

Fax : +1 450 476 1449

noria-mirabel@turbomeca.ca

Team Mexico 

Montes Urales 505 Piso 3 

Colonia Lomas de Chapultepec 11000 – Mexico DF 

noria-mexico@turbomeca.com.mx

For Africa, Europe, Middle East 

TURBOMECA-Noria 

Team Tarnos 

DVO Service NORIA 

40220 TARNOS – France 

Fax : +33 (0) 5 59 74 45 72 

noria-tarnos-arriel1@ turbomeca.fr

Team UK 

Concorde Way 

Segensworth North, Fareham 

Hants PO15 5RL - United Kingdom 

noria-tmuk@turbomeca.co.uk

Team Hamburg

Borsteler Chaussee 43 

22453 Hamburg – Germany 

Fax:+49 40 500 216 61 

noria-hamburg@turbomeca.de

For South America 

TURBOMECA-Noria 

Team Rio 

Rua Capitão Guynemer, 1626 – Xerém 

CEP : 25250-130 - Duque de Caxias - RJ – Brasil 

Fax : +55 21 2679 2794 

noria-rio@turbomeca.com.br

For Australasia, Oceania, Japan 

TURBOMECA-Noria

Team Sydney

115 Wackett St, Bankstown Airport 

Bankstown, NSW 2200 – Australia 

Fax : +61 2 9791 6708 

noria-sydney@turbomeca.com.au

For Asia Pacific 

TURBOMECA-Noria 

Team Singapore 

63 Loyang Way, Singapore 508753 

Fax:+65 6545 4978

noria.singapore@turbomeca.com.sg

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MANDATORY SERVICE BULLETIN 

8. Manpower 

A. At the operator's site 

- Personnel: One mechanic and one person qualified to perform a ground run check. 

- Time required: 4 man-hours. 

B. At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

- Personnel of approved Repair/Maintenance Center. 

- Time determined by the Repair/Maintenance Center as being appropriate for this level of 

intervention. 

C. At a TURBOMECA-approved Repair Center 

Not applicable 

9. Tooling and/or products 

A. At the operator's site 

- Mechanic's standard tooling. 

- Refer to TI X 292 72 2849. 

B. At a TURBOMECA-approved Service Center or at a TURBOMECA-approved 

Maintenance Center 

- Mechanic's standard tooling. 

- Refer to TI X 292 72 2850. 

C. At a TURBOMECA-approved Repair Center 

Not applicable. 

10. Weight and balance 

Not applicable. 

11. Publication references - ARRIEL 2B Maintenance Manual............................................................ Ref. X 292 M5 450 2. 

- ARRIEL 2B1 Maintenance Manual.......................................................... Ref. X 292 N5 450 2. 

- ARRIEL 2B1A Maintenance Manual ....................................................... Ref. X 292 P4 450 2. 

- ARRIEL 2B Spare Parts Catalog............................................................. Ref. X 292 M5 700 2. 

- ARRIEL 2B1 Spare Parts Catalog........................................................... Ref. X 292 N5 700 2. 

- ARRIEL 2B1A Spare Parts Catalog ........................................................ Ref. X 292 P4 700 2. 

- Technical Instruction .............................................................................. Ref. X 292 72 2849. 

- Technical Instruction .............................................................................. Ref. X 292 72 2850. 

12. Approval 

The technical information contained in this document is approved under the Design 

Organization Approval No. EASA.21J.070. 

This Mandatory SB is subject to an Airworthiness Directive. 

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MANDATORY SERVICE BULLETIN 

Variante/ 

Variant

SN M01/ 

NS M01

Variante/ 

Variant

SN M01/ 

NS M01

2B 124 2B1 1424 

2B 145 2B1 1509 

2B 162 2B1 1542 

2B 164 2B1 1654 

2B 482 2B1 1694 

2B 507 2B1 1733 

2B 536 2B1 1797 

2B 548 2B1 1891 

2B 550 2B1 1962 

2B 606 2B1 1983 

2B 622 2B1 1984 

2B 697 2B1 1995 

2B 776 2B1 2008 

2B 857 2B1 6107 

2B 874 2B1 6108 

2B 953 2B1 6143 

2B 1052 2B1 6151 

2B 1182 2B1 6163 

2B 1236 2B1 6182 

2B 18045 2B1 6193 

2B 18073 2B1 6196 

2B1 34 2B1 6301 

2B1 161 2B1 6351 

2B1 351 2B1 6463 

2B1 365 2B1 6497 

2B1 593 2B1 7377 

2B1 755 2B1 7405 

2B1 875 2B1 7434 

2B1 899 2B1 7452 

2B1 989 2B1 7456 

2B1 1052 2B1 18054 

2B1 1122 2B1 18082 

2B1 1139 2B1 18205 

2B1 1292 2B1 18251 

2B1 1397 2B1A 4080 

2B1 1423 2B1A 4480 

FIGURE 01 

Liste des modules M01 non concernés par ce SB Impératif 

List of modules M01 that are not concerned by the application of this Mandatory SB 

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MANDATORY SERVICE BULLETIN 

Objet : Attestation de remplacement du module M01 

Subject: Compliance certificate for module M01 replacement 

Important / Important notice :

Après application des instructions spécifiées dans ce SB Impératif, veuillez compléter la présente 

attestation et la retourner auprès de votre coordinateur NORIA local par courrier ou courriel ou fax, se 

reporter paragraphe 7.C. 

After application of the instructions specified in this Mandatory SB, please complete this certificate and return it 

to your local coordinator NORIA by mail or email or fax, refer to paragraph. 7.C. 

Information concernant le matériel / Equipment information 

Utilisateur

Customer 

N° Appareil

Aircraft S/N 

N/S - S/N Réf. - P/N TSN* TSO* CSN* CSO* 

Moteur 

Engine 

Module M01 déposé 

Removed module M01 

Module M01 installé

Installed module M01 

* TSN = Time Since New (Heures depuis neuf) TSO = Time Since Overhaul (Heures depuis RG) 

 CSN = Cycles Since New (Cycles depuis neuf) CSO = Cycles Since Overhaul (Cycles depuis RG) 

Opération effectuée par / Work performed by: 

Je certifie que le module identifié ci-dessus a été installé selon les directives de ce SB Impératif. 

I certify that the above-mentioned module has been installed according to the directives given in this 

Mandatory SB. 

Date [JJ / MMMM (en lettre) / AAAA 

ou/or DD / MMMM (letter) / YYYY] Nom / Print name Fonction / Job title 

 

ANNEXE / APPENDIX 

Signature : 

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