# ASB No. AS365-05.00.60

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Revision 2 2012-10-09 This document is available on the Internet: www.eurocopter.com/techpub 

### Civil version(s): N1, N2, N3

Military version(s): F, Fi, K



# ALERT SERVICE BULLETIN

SUBJECT : TIME LIMITS - MAINTENANC E CHECKS - Tail Rotor Hub (TRH)

Visual check of 10-blade and 11-blade TRH hubs

ATA 64



### Revision No. Date of issue

Revision 0 2011-04-11

Revision 1 2011-07-20

Revision 2 2012-10-09



### Summary :

The purpose of this ALERT SERVICE BULLETIN is to do a visual check of the 10-blade and 11-blade TRH hubs

with removal of the Tail Gearbox (TGB) cover.



### Reason for last Revision:

The purpose of Revision 2 of this ALERT SERVICE BULLE TIN is to extend the mandatory visual check of the tail

rotor hub to AS365 helicopters equipped with an 11-blade TRH, only for version N3.



### Compliance :

EUROCOPTER renders compliance with Revision 2 of this ALERT SERVICE BULLETIN mandatory. For the attention of

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### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

For AS365 helicopter versions N1, N2, N3, F, Fi and K equipped with a 10-blade TRH

,

Helicopters equipped with a rotor hub P/ N 365A33351100, 365A33351101 or 365A33351102.

Only for AS365 helicopter version N3 equipped with an 11-blade TRH

,

Helicopters equipped with a rotor hub P/N 365A33216001 or 365A33216003.

1.A.2. Non-installed equipment

Not applicable.



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.



### 1.C. REASON

Revision 0 :

During a 2T inspection on an AS365 helicopter equipped with a 10-blade TRH, t he technician found cracks

on the TRH hub.

Pending the results of additional investigations, EU ROCOPTER recommended that you perform a visual

check of the 10-blade TRH hub, with removal of the Tail Gearbox (TGB) cover, every 110 flying hours.

Revision 1 :

Subsequent to a second case similar to the first ca se of cracks being detected on the TRH hub, and pending

further investigation to determine the cause of these cracks, EUROCOPTER rendered mandatory the visual

check of the 10-blade TRH hub, with removal of the TGB cover, every 55 flying hours.

Revision 2 :

The current analysis has led EUROCOPTER to extend the visual check of the rotor hub to AS365

helicopters equipped with an 11-blad e TRH, only for version N3.

Revision 2 does not affect compliance with Revision 1 of this ALERT SERVICE BULLETIN, for helicopters

equipped with a 10-blade TRH.

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### 1.D. DESCRIPTION

Revision 0 :

Compliance with Service Bulletin Revision 0 consisted in performing a visual check, without removal of

the 10-blade TRH hub, with removal of the TGB cove r, at intervals not exceeding 110 flying hours.

Revision 1 :

Compliance with Revision 1 of this ALERT SERVICE BULLETIN consisted in rendering mandatory the visual

check without removal of the 10-blade TRH hub, with removal of the TGB cover, every 55 flying hours.

Revision 2 :

Compliance with Revision 2 of this ALERT SERVICE BULLETIN consists in:

- Extending the mandatory visual check of the TRH hub to AS365 he licopters equipped with an 11-blade

TRH, only for version N3.

- Integrating details on the check procedure in paragraph 3.



### 1.E. COMPLIANCE

1.E.1. Compliance at the works

Not applicable.

1.E.2. Compliance in service

Helicopters/installed equipment :

For helicopters equipped with a 10-blade TRH

Comply with paragraph 3. of this ALERT SERVICE BULLETIN before reaching 55 flying hours following

receipt of Revision 1 of this ALERT SERVICE BULLETIN, issued on July 20, 2011.

Then,

Comply with paragraph 3. at inte rvals not exceeding 55 flying hours.

For helicopters equipped with an 11-blade TRH (only version N3)

Comply with paragraph 3. of this ALERT SERVICE BULLETIN before reaching 55 flying hours following

receipt of Revision 2, issued on the dat e indicated at the bottom of the page,

then,

comply with paragraph 3. at intervals not exceeding 55 flying hours.

Non-installed equipment :

Not applicable

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### 1.F. APPROVAL

Approval of modifications :

Not applicable.

Approval of this document :

The technical information contained in this Service Bulletin Revision 0 was approved

on April 08, 2011 under the authority of EASA Design Organization Approv al No. 21J.056 fo r helicopters of

civil versions subject to an Airworthiness Certificate.

The technical information contained in this Service Bulletin Revision 0 was approved

on April 08, 2011 under the prerogatives of the recogn ition of design capability FRA21J-002-DGA for French

Government helicopters.

The technical information contained in this Service Bulletin Revision 0 was approved

on April 08, 2011 by the EUROCOPTER Airworthi ness Department for export military versions.

The technical information contained in Revision 1 of this ALERT SERVICE BU LLETIN was approved

on July 20, 2011 under the authority of EASA Design Organisation Appr oval No. 21J.056 for civil version

helicopters subject to an Ai rworthiness Certificate.

The technical information contained in Revision 1 of this ALERT SERVICE BU LLETIN was approved

on July 20, 2011 under the prerogatives of the recogn ition of design capability FRA21J-002-DGA for French

Government helicopters.

The technical information contained in Revision 1 of this ALERT SERVICE BUILLETIN was approved

on July 20, 2011 by the EUROCOPTER Airworthi ness department for export military versions.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 2 was approved

on October 09, 2012 under t he authority of EASA Design Organizati on Approval No. 21J.056 for helicopters

of civil versions subject to an Airworthiness Certificate.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 2 was approved

on October 09, 2012 under the prerogatives of the reco gnition of design capability FRA21J-002-DGA for

French Government helicopters.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 2 was approved

on October 09, 2012 by the EUROCOPTER Airworthi ness Department for export military versions.

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### 1.G. MANPOWER

EUROCOPTER recommends that compliance with this ALERT SERVICE BULLETIN be ensured by

personnel with the following qualification:

Qualification: 1 Mechanica l Engineering Technician.

The time for the operations is given for information purposes, for a standard configuration.

Time for the operations: Approx. 1 hour for one Me chanical Engineering Technician for the check.



### 1.H. WEIGHT AND BALANCE

Not applicable.



### 1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.



### 1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD

Not applicable.



### 1.K. REFERENCES

The following documents are necessary for comp liance with this ALERT SERVICE BULLETIN:

Maintenance Manual (MET):

MET: 60.00.00.300: Rotors - Gene ral mechanical instructions

MET: 64.21.01.402: TRH 365A33.0040 - Tail ro tor assembly : Removal - Installation

MET: 64.21.01.601: TRH 365A33. 0040 - On-condition maintenance

MET: 64.21.02.406: Quiet fenestron - Tail rotor hub body : Removal - Installation

MET: 64.21.02.605: Quiet fenestron - Detailed inspection of the TRH

MET: 64.21.02.606: Quiet fenest ron - TRH inspection criteria

Repair Manual (MRR):

MRR: 64.21.01.726: Fit and clearances: Tail rotor

Standard Practices Manual (MTC):

MTC: 20.02.09.101: Crack detection thro ugh dye-penetrant inspection: General

MTC: 20.07.03.401: Technical instructions - Instru ctions applicable during maintenance operations on

mechanical assemblies

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### 1.L. DOCUMENTS AFFECTED

Not applicable.



### 1.M. INTERCHANGEABILITY OR MIXABILITY OF PARTS

Not applicable.

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### 2. MATERIAL INFORMATION

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT

Price

For any information concerning the kits and/or co mponents, contact the EUROCOPTER Network Sales &

Customer Relations Department.

Availability

The kits and/or components are delivered on the operator's order.

Procurement conditions

Order the required quantity (unless otherwise specified)

from

EUROCOPTER

Etablissement de Marignane

Direction Ventes et Relations Client (ECR)

13725 MARIGNANE CEDEX

FRANCE



### NOTE 1

On the purchase order, please specify the mode of transport,

the destination and the serial numbers of the helicopters to be

modified.



### NOTE 2

For ALERT SERVICE BULLETINS, order by:

Telex: HELICOP 410 969F

Fax: +33 (0)4.42.85.99.96



### 2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

Not applicable.

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### 2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONENT

Kits or components to be ordered for one helicopter or one assembly :

Old Designation Qty New Part Number Item Part Number Instructions

For a 10-blade TRH :

Rotor hub A/R 365A33-3511-00 1 365A33-3511-00 Replace if cracks are

detected

Rotor hub A/R 365A33-3511-01 2 365A33-3511-01 Replace if cracks are

detected

Rotor hub A/R 365A33-3511-02 3 365A33-3511-02 Replace if cracks are

detected

For an 11-blade TRH :

Rotor hub A/R 365A33-2160-01 4 365A33-2160-01 Replace if cracks are

detected

Rotor hub A/R 365A33-2160-03 5 365A33-2160-03 Replace if cracks are

detected

Products to be ordered separately :

Refer to the Tasks and Work Cards specified in this Service Bulletin.

The products can be ordered separately from t he INTERTURBINE AVIATION LOGISTICS company.

Website: http://www.interturbine.com

Phone: +49.41.91.809.300

AOG: +49.41.91.809.444



### 2.D. MATERIAL TO BE RETURNED

Not applicable.

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### 3. ACCOMPLISHMENT INSTRUCTIONS

3.A. GENERAL

- Read and comply with the general mechanical in structions as per MET Work Card 60.00.00.300.

- Read and comply with the maintenance instructions applicable to mechanical assemblies as per MTC Work

Card 20.07.03.401.



### NOTE 1

The illustrations given in Figur es 1 to 4 show a 10-blade

TRH. The inspection areas vi sible on these illustrations are

identical for 10-blade and 11-blade TRHs.



### 3.B. OPERATIONAL PROCEDURE

3.B.1. Preliminary steps (Figure 2)

- Install the access equipment.

- If necessary, release the rotor brake.

- Remove the TGB fairing cover (b) (Detail B, Figure 2).

3.B.2. Check for cracks (Figures 1 to 4)

- Using a light source, check for cracks on the entire Area C (Detail A, Figure 1) of the TRH hub (a) on the

TGB (c) side (Detail C, Figure 2); pay particular attention around screws (e) (Detail A, Figure 1).

. Perform the check between the lower part of the TG B (c) and its fairing (d) (Details D and E, Figure 3).

. Turn the tail rotor by hand to check the entire Area C (Detail A, Figure 1).

- If in doubt on the presence of cracks:

. Remove the rotor hub (a) from the TRH:

- as per MET Work Card 64.21.02.406 for a 10-blade TRH.

- as per MET Work Card 64.21.01.402 for an 11-blade TRH.

. Perform a non-destructive test. (Example: Dye-penetrant inspection as per MTC Work

Card 20.02.09.101 and Work Card 20.02.09.601).

Interpretation of the results :

- If no cracks are found on the TRH hub (a):

. If necessary, install the TRH hub (a):

- as per MET Work Card 64.21.02.406 for a 10-blade TRH.

- as per MET Work Card 64.21.01.402 for an 11-blade TRH.

. Comply with paragraph 3.B.3.

# ASB No. AS365-05.00.60

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. If necessary, remove the TRH hub (a):

- as per MET Work Card 64.21.02.406 for a 10-blade TRH.

- as per MET Work Card 64.21.01.402 for an 11-blade TRH.

. Discard the TRH hub (a).

. Perform a detailed check and a dimensional check of:

- shouldered slide bushes (h) (Detail G, Figure 4),

- clamping plate (g),

- torsion bar bolts (j),

- splined flange (f),

as per MET Work Cards 64.21.02.605 and 64.21.02.606 for a 10-blade TRH,

as per MET Work Card 64.21.01.601 and MRR Work Card 64.21.01.726 for an 11-blade TRH.

. Install:

- a rotor hub (1), (2) or (3) as per MET Work Card 64.21.02.406 for a 10-blade TRH,

- a rotor hub (4) or (5) as per MET Work Card 64.21.01.402 for an 11-blade TRH.

. Inform immediately the Customer Serv ice Technical Support Department by:

Phone: + 33 (0)4.42.85.20.51

Fax: + 33 (0)4.42.85.99.66

E-mail: DynComp.Technical-Support@eurocopter.com

. Comply with paragraph 3.B.3.

3.B.3. Final steps (Figure 2)

- Install the TGB fairing cover (b) (Detail B, Figure 2).

- If necessary, apply the rotor brake.

- Remove the access equipment.



### 3.C. IDENTIFICATION

Identification of this document :

- For helicopters equipped with a 10-blade TRH:

. Record initial compliance with Revision 1 of this ALERT SERVICE BULLETIN in the helicopter documents.

- For helicopters equipped with an 11-blade TRH (only version N3):

. Record initial compliance with this ALERT SER VICE BULLETIN Revision 2 in the helicopter documents.



### 3.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable.

# ASB No. AS365-05.00.60

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Figure 1: TRH hub 

## a

1

2

3

4

5

TGB

side

A rea C e A - B - C

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Figure 2: Location of the ar ea to be checked (Area C) 

## b

c

d

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Figure 3: Visual check of Area C 

## a

1

2

3

4

5

d c

d c

a

1

2

3

4

5

e

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Figure 4: Detailed check and dimensional check



## j

f

g h