# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 1/11

This document is available on the internet: www.eurocopter.com/techpub 

### Civil version(s): B, BA, BB, B1, B2, B3, D Military version(s): L1



# ALERT SERVICE BULLETIN

SUBJECT : ROTOR FLIGHT CONTROLS – Tail gearbox

Check of the Tail gearbox (TGB) casing assembly.

Revision No. Date of issue

Revision 0 2011-05-18



### Summary :

To perform a non-destructive inspection (for example a dye-penetrant inspecti on) of the attachment yokes of the control lever of the TGB casing assembly in order to check for cracks.



### Compliance :

EUROCOPTER renders compliance with th is ALERT SERVICE BULLETIN mandatory. For the attention of

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 2/11

This document is available on the internet: www.eurocopter.com/techpub 

### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

Tail gearboxes (TGB) equipped with TGB casing assembly MP/N 350A33-1090-02 with the following serial numbers:

MA47577, MA47585, MA47587, MA47588, MA 47589, MA47590, MA47591, MA47592, MA47593,
MA47597, MA47598, MA47599, MA47600, MA 47602, MA47604, MA47606, MA47610, MA47613,
MA47615, MA47617, MA47619, MA47620, MA 47621, MA47622, MA47623, MA47624, MA47626,
MA47628, MA47631.



### NOTE Refer to the Log card (FM) of the TGB to identify the actual configuration of the helicopter.

1.A.2. Non-installed equipment

TGB casing assemblies listed in paragraph 1.A.1.



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.



### 1.C. REASON

Following repair of the manufacturing mold from t he TGB casing assemblies, the dye-penetrant inspection performed after machining of the attachment yokes of the control lever has revealed cracks on some TGB casing assemblies. EUROCOPTER has identified the TGB casing assemblies which may show cracks.

The presence of cracks on at least one of the attachment yokes of the control lever can lead to the loss of tail rotor pitch control.

This is the reason why EUROCOPTER renders the chec k for cracks in the attachment yokes of the control lever of the TGB casing assemblies mandatory, by intr oducing a non-destructive inspection (for example a dye-penetrant inspection).

Revision 0 of this ALERT SERVICE BULLETIN will form the subject of an EASA Airworthiness Directive.



### 1.D. DESCRIPTION

Compliance with this ALERT SERVICE BULLETIN consists in disassembling the control lever in order to perform a non-destructive inspection (for example a dye- penetrant inspection) of the attachment yokes of the control lever and, if necessary, replace the TGB.

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 3/11

This document is available on the internet: www.eurocopter.com/techpub 

### 1.E. COMPLIANCE

1.E.1. Compliance at the works

The operations are to be carried out by EUROCOPTER.

Helicopters/installed equipment :

Comply with paragraph 3. before delivery.

Non-installed equipment :

Comply with paragraph 3.B.2. before delivery.

1.E.2. Compliance in service

The operations on the helicopter are to be performed by the operator.

The operations on non-installed equipment are to be performed by the operator.

Helicopters/installed equipment :

For TGB casings having logged less than 550 flying hours since new: Comply with paragraph 3. of this ALERT SERVICE BU LLETIN at the latest when reaching 660 flying hours or 26 months since new (the first limit reached is applicable).

For TGB casings having logged more than 550 flying hours since new: Comply with paragraph 3. of this ALERT SERVICE BULLETIN within 110 flying hours or no later than within 13 months following receipt of this ALERT SERVICE BULLETIN, issued on the date indicated at the bottom of the page.

Non-installed equipment :

Comply with paragraph 3.B.2. before installation on the helicopter and no later than within 12 months following receipt of this ALERT SERVICE BULLETIN, i ssued on the date indicated at the bottom of the page.



### 1.F. APPROVAL

Approval of modifications :

Not applicable.

Approval of this document :

The technical information contained in this AL ERT SERVICE BULLETIN Revision 0 was approved on May 17, 2011 under the authority of EASA Design Organization 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 0 was approved on May 17, 2011 under the prerogatives of the recognit ion of design capability FRA21J-002-DGA for French Government helicopters.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 0 was approved on May 17, 2011 by the EUROCOPTER Airworthine ss Department for export military versions.

# ASB No. AS350-65.00.46

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This document is available on the internet: www.eurocopter.com/techpub 

### 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: approximately 2 hours for one Mechanical Engineering Technician.



### 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 compliance with this ALERT SERVICE BULLETIN.

MTC: 20.02.09.101 – Crack detection – General principl es applicable to the dye-penetrant inspection procedure

MTC: 20.02.09.601 – Crack detection – Checking structural parts and components using the dye-penetrant inspection procedure MTC: 20.04.01.401 – Cleaning – Cleaning mechanical parts MTC: 20.04.02.401 – Stripping – St ripping organic surface coatings MTC: 20.04.04.403 – Surface treatment before painting – Surface treatment chemical conversion with

"Alodine 1200" MTC: 20.04.05.101 – Paint and primer application proc edure – General information concerning painting means and paint touch-ups MTC: 20.04.05.402 – Paint and primer applicati on procedure – EPOXY primer P05 – P20 scheme MTC: 20.04.05.403 – Paint and primer app lication procedure – Paint scheme 4080 MTC: 20.04.05.601 – Paint and primer applicati on procedure – Checks after paint application MTC: 20.08.05.101 – General rules applicable to ai rcraft – Raising and updating the equipment log card (F.M.E.) for equipment follow-up

For AS350 helicopter versions B2 and B3 : AMM: 60-00-00, 3-1 – General instructions - Mechanics
AMM: 65-21-00, 4-1 – TGB removal
AMM: 65-21-00, 4-2 – TGB installation

For AS350 helicopter versions B, BA, BB, B1, D and L1 : MET: 60.00.00.301 – Rotors – General – General instructions MET: 65.20.00.401 – Tail gearbox – TGB, tail ro tor hub and control plate – Removal-Installation

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 5/11

This document is available on the internet: www.eurocopter.com/techpub 

### 1.L. DOCUMENTS AFFECTED

Not applicable.



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

Not applicable.

# ASB No. AS350-65.00.46

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### 2. MATERIAL INFORMATION

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT

Price

For all information concerning kits and/or components, contact the Sales and Customer Relations Department of the EUROCOPTER Network.

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.



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

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

Former Designation Qty New P/N Item

No. P/N Instructions

Tail gearbox A/R 350A33-0200-06 1 / / Tail gearbox A/R 350A33-0200-07 2 / /

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 7/11

This document is available on the internet: www.eurocopter.com/techpub Products to be ordered separately :

Designation Qty Product P/N CM Item

No.
Chemical conversion agent (Alodine 1200) A/R N8716206112 CM 316 3
EPOXY Primer (P05) A/R DHS186-111-20 CM 487 4
Top coat paint (P81) A/R 4080 CM 498 5

Refer to the table above and the Work Cards and Tasks specified in this ALERT SERVICE BULLETIN.

The products can be ordered separately from t he INTERTURBINE 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

If a crack is found on at least one of the control lever yokes of the TGB casing assembly, return the TGB to EUROCOPTER in accordance with the procedure described in Service Letter No. 1567-00-02.

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 8/11

This document is available on the internet: www.eurocopter.com/techpub 

### 3. ACCOMPLISHMENT INSTRUCTIONS

3.A. GENERAL

Read and comply with the general mechanical instructions as per AMM Task 60-00-00, 3-1. Read and comply with the general instructions concerni ng the rotors as per MET Work Card 60.00.00.301. Read and comply with the general information concerning painting means and paint touch-ups as per

MTC Work Card 20.04.05.101.



### 3.B. OPERATIONAL PROCEDURE

3.B.1. Preliminary steps

Install the access equipment.

3.B.2. Check for cracks in input yokes (a) of TGB casing assembly (d) (Figures 1 and 2)

- Remove control lever (b) (Figure 1) as per AMM Task 65-21-00, 4-1 or MET Work Card

65.20.00.401. - Strip the areas to be inspected (Z) (Figure 2) as per MTC Work Card 20.04.02.401. - Perform a non-destructive inspection of each area to be inspected (Z) (for example a dye-penetrant

inspection as per MTC Work Cards 20.02.09.101 and 20.02.09.601). - Check for cracks in the inspected areas (Z):

. If there is a crack in at least one of the inspected areas (Z) :

- Remove TGB (c) as per AMM Task 65-21-00, 4-1 or MET Work Card 65.20.00.401. - Install a TGB (1) or (2) as per AMM Task 65- 21-00, 4-2 or MET Work Card 65.20.00.401.

- Contact the Customer Service Technical Support Department by:

Tel.: + 33 (0)4 42 85 99 51 Fax: + 33 (0)4 42 85 99 66. E-mail: DynComp.Technical-Support@eurocopter.com

- Return TGB (c) to EUROCOPTER in accordance with paragraph 2.D.

. If there is no crack in all of the inspected areas (Z) :

- Clean the inspected areas (Z) as per MTC Work Card 20.04.01.401. - Do a treatment with Alodine 1200 (3) (not represent ed) on the surfaces of the inspected areas (Z) as

per MTC Work Card 20.04.04.403. - Apply EPOXY P05 primer (4) (not represented) to the inspected areas (Z) as per MTC Work

Card 20.04.05.402. - Apply grey P81 top coat paint (5) (not represented) to the inspected areas (Z) as per MTC

Work Card 20.04.05.403. - Do the check after application of paint to the inspected areas (Z) as per MTC Work Card

20.04.05.601. - Install control lever (b) as per AMM Task 65 -21-00, 4-2 or MET Work Card 65.20.00.401.

3.B.3. Final steps

Remove the access equipment.

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 9/11

This document is available on the internet: www.eurocopter.com/techpub 

### 3.C. IDENTIFICATION

Identification of this document :

Record compliance with this ALERT SERVICE BULLETIN on the log card (F M) of the TGB as per MTC Work

Card 20.08.05.101.



### 3.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable.

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 10/11

This document is available on the internet: www.eurocopter.com/techpub Figure 1: Control lever 

## A



# A

b c
1 ou/or 2

a (see Figure 2) 

## B

# ASB No. AS350-65.00.46

Revision 0 2011-05-18 Approved under EASA DOA No. 21J.056. Page 11/11

This document is available on the internet: www.eurocopter.com/techpub Figure 2: TGB casing assembly (front view) 

# B

Z d

Z a (see Figure 1)