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# EMERGENCY



# ALERT SERVICE BULLETIN

SUBJECT: TIME LIMITS - MAINTENANCE CHECKS

Check of the Tail Rotor laminated half bearings

ATA: 05, 64

AIRCRAFT

CONCERNED NUMBER Version(s)

Civil Milita ry

AS350 05.00.71 B, BA, BB, D, B1, B2, B3 L1

AS355 05.00.63 E, F, F1, F2, N, NP

AS550 05.00.46 A2, C2, C3, U2

AS555 05.00.42 AF, AN, SN, UF, UN



### Revision No. Date of issue

Revision 0 2012-09-19

Revision 1 2012-11-26

Revision 2 2012-12-19



### Summary:

The purpose of this ALERT SERVICE BULLETIN is to ma ke the periodic check of the laminated half bearing s

mandatory.



### Reason for last Revision:

The purpose of Revision 2 is:

- to extend the applicability to all laminated half bearing part numbers.

- to specify permissible criteria for laminated hal f bearings in the table of paragraph 3.B.2.



### Compliance:

Compliance with this ALERT SERVICE BULLETIN is mand atory. For the attention of

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### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

On helicopters equipped with a tail rotor PRE MOD 0 75601 on which laminated half bearings (all part

numbers) are installed.



### NOTE 1

The laminated half bearings installed on helicopter s equipped with a tail rotor POST MOD 075601 are subj ect to

compliance with ALERT SERVICE BULLETINS

No. 01.00.65 (AS350 version B3 “e”) and

No. 01.00.24 (AS550 version C3 “e”).

1.A.2. Non-installed equipment

Not applicable.



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.



### 1.C. REASON

Revision 0:

Premature cracks in laminated half bearings equippi ng Tail Rotor blades have recently been detected on

several AS350 B3 helicopters POST MOD 075601.

Because the laminated half bearing deteriorates pro gressively, EUROCOPTER has issued Safety

Information Notice No. 2482-S-64 to remind all oper ators of the particular attention that must be give n during

the visual check of the elastomeric part of the lam inated half bearings during the ALF check.

Deterioration of this part can generate in-flight v ibrations, felt mainly in the pedals, requiring the pilot to land

as soon as possible.

In order to prevent the occurrence of in-flight vib rations, EUROCOPTER issues this Service Bulletin to

enhance the laminated half bearing inspection proce dure so as to detect any deterioration of the beari ngs as

early as possible.

EUROCOPTER is conducting all the necessary investig ations with operators and the supplier of the

laminated half bearings in order to identify the ca use of the phenomenon.

Revision 1:

Following further analyses, EUROCOPTER confirmed th at the reason for the behavior of the laminated hal f

bearings proving at times to be faulty was related to the embodiment of modification 075601.

For this reason, EUROCOPTER issued ALERT SERVICE BU LLETINS No. 01.00.65 (AS350 version B3 “e”)

and No. 01.00.24 (AS550 version C3 “e”) concerning the maintenance to be applied to helicopters equipp ed

with a Tail Rotor POST MOD 075601.

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Revision 2 2012-12-19 This document is available on the internet: www.eurocopter.com/techpub Furthermore, the analyses conducted following the e vent described in Safety Information Notice

No. 2507-S-64 lead EUROCOPTER to reconsider the fun ction of the laminated half bearings. Consequently,

EUROCOPTER makes the periodic check of the laminate d half bearings mandatory.

This decision is formalized by converting Service B ulletins No. 05.00.71 (AS350), No. 05.00.63 (AS355)

, No. 05.00.46 (AS550) and No. 05.00.42 (AS555) into ALERT SERVICE BULLETINS.

Moreover, Revision 1 of this ALERT SERVICE BULLETIN specifies the criteria for replacement of the

laminated half bearings for helicopters equipped wi th a tail rotor PRE MOD 075601.

Revision 1 of this ALERT SERVICE BULLETIN affects c ompliance with Revision 0.

Revision 2:

The purpose of Revision 2 is:

- to extend the applicability to all laminated half bearing part numbers.

- to specify permissible criteria for laminated hal f bearings in the table of paragraph 3.B.2.



### 1.D. DESCRIPTION

- Check to make sure there is no deterioration of t he laminated half bearings.

- Interpretation of the results.



### 1.E. COMPLIANCE

1.E.1. Compliance at the works

Not applicable.

1.E.2. Compliance in service

Helicopters/installed equipment:

Comply with paragraph 3. of this ALERT SERVICE BULL ETIN at the latest after the last flight of the day

(ALF) following receipt of Revision 2 of this ALERT SERVICE BULLETIN, issued on the date indicated at the

bottom of the page.

Then,

Comply with paragraph 3. of this ALERT SERVICE BULL ETIN after each last flight of the day (ALF) withou t

exceeding 10 flying hours between two checks.

Non-installed equipment:

Not applicable.



### 1.F. APPROVAL

Approval of modifications:

Not applicable.

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Revision 2 2012-12-19 This document is available on the internet: www.eurocopter.com/techpub Approval of this document:

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

on September 19, 2012 under the authority of EASA D esign Organization Approval No. 21J.056 for

helicopters of civil versions subject to an Airwort hiness Certificate.

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

on September 19, 2012 under the prerogatives of the recognition of design capability FRA21J-002-DGA fo r

French Government helicopters.

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

on September 19, 2012 by the EUROCOPTER Airworthine ss Department for export military versions.

The technical information contained in this ALERT S ERVICE BULLETIN Revision 1 was approved

on November 26, 2012 under the authority of EASA De sign Organization Approval No. 21J.056 for

helicopters of civil versions subject to an Airwort hiness Certificate.

The technical information contained in this ALERT S ERVICE BULLETIN Revision 1 was approved

on November 26, 2012 under the prerogatives of the recognition of design capability FRA21J-002-DGA for

French Government helicopters.

The technical information contained in this ALERT S ERVICE BULLETIN Revision 1 was approved

on November 26, 2012 by the EUROCOPTER Airworthines s Department for export military versions.

The technical information contained in this ALERT S ERVICE BULLETIN Revision 2 was approved

on December 19, 2012 under the authority of EASA De sign Organization Approval No. 21J.056 for

helicopters of civil versions subject to an Airwort hiness Certificate.

The technical information contained in this ALERT S ERVICE BULLETIN Revision 2 was approved

on December 19, 2012 under the prerogatives of the recognition of design capability FRA21J-002-DGA for

French Government helicopters.

The technical information contained in this ALERT S ERVICE BULLETIN Revision 2 was approved

on December 19, 2012 by the EUROCOPTER Airworthines s Department for export military versions.



### 1.G. MANPOWER

For compliance with this ALERT SERVICE BULLETIN, EU ROCOPTER recommends the following personnel

qualifications:

Qualification: 1 Mechanical Aircraft Technician or 1 crew member who has received an appropriate train ing

by the operator’s maintenance organization, if auth orized by local authorities.

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

Time for the operations: approximately 5 minutes fo r the check.



### 1.H. WEIGHT AND BALANCE

Not applicable.

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### 1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.



### 1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD

Not applicable.



### 1.K. REFERENCES

The documents required for compliance with this ALE RT SERVICE BULLETIN are as follows:

For AS350 helicopter versions BA, BB, B, D, L1, B1, AS550 helicopter versions A2, C2, U2 and all

AS355 and AS555 helicopter versions:

MRR: 64.10.00.704: Tail rotor blades - Replacing th e laminated bearings (before application of

MOD 07 5552)

MRR: 64.10.00.771: Tail rotor blades - Mounting/Rem oval of tail rotor transmission

For AS350 helicopter versions B2, B3 and AS550 heli copter version C3:

AMM: 64-10-00,4-3: Tail rotor blade: Removal - Lami nated main bearing

AMM: 64-10-00,4-4: Tail rotor blade: Installation - Laminated bearings



### 1.L. DOCUMENTS AFFECTED

EUROCOPTER will modify the following documents with respect to this Service Bulletin:

- Maintenance Manual (MET),

- Aircraft Maintenance Manual (AMM),

- Master Servicing Manual (MSM).

The documents affected will be updated as part of a future revision.



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

Not applicable.

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### 2. MATERIAL INFORMATION

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT

Not applicable.



### 2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

Not applicable.



### 2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONEN T

Products to be ordered separately:

Refer to the Work Cards and Tasks referenced in th is ALERT SERVICE BULLETIN.

The products can be ordered separately from the IN TERTURBINE AVIATION LOGISTICS company.

Website: http://www.interturbine.com

Telephone: +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

Not applicable.



### 3.B. OPERATIONAL PROCEDURE

3.B.1. Check of the laminated half bearings

Pressure face:

- Position both Tail Rotor blades horizontally.

- Apply an axial perpendicular load (F) to one Tail Rotor blade (a) (See Figure 1).



### NOTE 1

The load must be applied by hand to the pressure fa ce of the

blade, taking care not to reach the extreme positio n against the

tail rotor hub.

- While maintaining the load, visually check all th e visible faces of the laminated half bearings (fro nt face and

side faces) in area B of DETAIL A, in order to dete ct either of the following:

. separation between the elastomer and the metal parts (see example in Figure 3),

. a crack in the elastomer (see example in Figure 4),

. extrusion (see example in Figure 4).



### NOTE 2

A flashlight can be used to facilitate the check.

- Interpret the results in accordance with paragrap h 3.B.2.

- Repeat the operation by applying the same load to the other blade in order to check the other lamina ted

half bearing, then interpret the results in accorda nce with paragraph 3.B.2.

Suction face:

- Stand between the rotor and the tail boom.

- Apply an axial perpendicular load (G) to one Tail Rotor blade (a), on the suction face side (See Fig ure 2).



### NOTE 3

The load must be applied by hand to the suction fac e of the

blade.

- While maintaining the load, visually check all th e visible faces of the laminated half bearings (fro nt face

and side faces) in area C (Figure 2), in order to d etect extrusion (see example in Figure 4).



### NOTE 4

A flashlight can be used to facilitate the check.

- Interpret the results in accordance with paragrap h 3.B.2.

- Repeat the operation by applying the same load to the other blade in order to check the other lamina ted

half bearing, then interpret the results in accorda nce with paragraph 3.B.2.

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- If there is no separation, crack or extrusion, n o maintenance is required.

- If there is separation, a crack or extrusion, ref er to the following criteria:

Permissible deteriorat ion

without repair Repair Deterioration requiring replacement

Laminated

bearings

(Figures 3 and

4)

Laminated

area Separations and/or cracks:

Deteriorations permitted as

long as the criteria requiring

replacement are not

reached None Continuous deterioration > :

L > 5mm (.196 in.) and P > 2mm (.078 in.)

(See Figure 3)

- replacement of the damaged component

(as per AMM 64-10-00,4-3 and

64-10-00,4-4 or MET 64.10.00.704 and

64.10.00.771)

Colors (shiny marks) on the

side faces None Deterioration permitted

Marks without cracks None Deterioration permitted

Extrusion without separation

or crack meeting the

replacement criteria as per

column “Deterioration

requiring replacement”

Remove the extrusion

particles with your finger (if

possible).

Monitor that there is no

separation or crack in

accordance with the

replacement criteria as per

column “Deterioration

requiring replacement” None

Extrusion with separation or crack

meeting the above replacement criteria



### 3.C. IDENTIFICATION

Identification of this document:

Record initial compliance with this document in th e helicopter documents.



### 3.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable.

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# A

DETAIL A



# B F

F

a



# B

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## G

G



# C a

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separation

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Figure 4 - Example of extrusion (continuous line) a nd cracks (dotted line) Example of crack Example of extrusion

Example of extrusion