### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 1/14

2008.05.07 EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE C EDEX F RANCE



# EMERGENCY



# ALERT SERVICE BULLETIN

DAUPHIN NUMBER VERSIONS

Civil: 

### N,N1,N2,N3. 

# AS 365 63.00.17 Military: 

### F,Fs,Fi,K. 

# AS 565 63.00.12 Military: 

### AA,MA,MB,SA,SB,UB

Civil: 

### B,B1 

# EC 155 63A011

Civil: 

### G1 

# SA 366 65.03 Military: 

### GA

Civil: 

### C,C1,C2,C3 

# SA 360/SA 365 65.47

SUBJECT: MAIN ROTOR DRIVE

Check of the Main Gearbox Casing (to make sure that there is no corrosion in the area of the servo-control attachment fittings)

REVISION No. DATE OF APPROVAL DATE OF ISSUE

Revision 0 On: May 06, 2008 2008.05.07

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

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 2/14

2008.05.07 

### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters / Installed equipment:

Main Gearboxes (MGBs), all part numbers:

- New MGBs delivered until December 5, 2007 (inclusi ve), or installed on new helicopters delivered until

December 5, 2007 (inclusive) (refer to the c onformity certificate of the helicopter), - MGBs newly overhauled or repai red before September 30, 2008.

1.A.2. Non-installed equipment

Main Gearboxes (MGBs), all part numbers:

- New MGBs delivered until December 5, 2007 (inclusive), - MGBs newly overhauled or repai red before September 30, 2008.



### NOTE 1

This ALERT SERVICE BULLETN does not apply to:

- New MGBs delivered after December 5, 2007 (date recorded on the equipment log card).

- MGBs newly overhauled or repaired after

September 30, 2008 (date recorded on the equipment log card). - MGBs installed on new helicopters (refer to the

conformity certificate of the helicopter) delivered after
December 5, 2007.



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.



### 1.C. REASON

To make sure that there is no corrosion in the lo wer area located between the two Main Gearbox casing

servo-control attachment ribs if there is a bead of PR sealing compound on the lower part of the servocontrol attachment fittings.

This ALERT SERVICE BULLETIN will form the s ubject of an DGAC Airworthiness Directive.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 3/14

2008.05.07 1.D. DESCRIPTION

EUROCOPTER has received some reports of at mospheric corrosion on the Main Gearbox casing
lower area, between the two servo-control anchor ing fitting attachment ribs (see Figure 1). The examinations and analyses of this occurrence have revealed that this corrosion results from an area trapped under the anchoring fittings. This trapped area is associated with a bead of PR sealing compound on the lower part of the fitting/casing attachment.

This occurrence of corrosion weakens this area of the casing and could, in time, lead to crack initiation and crack growth which could cause this area to fail and lead to the loss of control of the helicopter.

Consequently, EUROCOPTER renders compliance wi th the measures defined in this ALERT SERVICE BULLETIN, mandatory.



### 1.E. COMPLIANCE

1.E.1. Compliance at the works

1.E.1.a. On helicopters / installed equipment: Not applicable.

1.E.1.b. Non-installed equipment: Not applicable.

1.E.2. Compliance in operation: By the operator.

1.E.2.a. On helicopters / installed equipment:

Comply with paragraph 2.B.2. at the latest with in 15 flying hours following receipt of this ALERT SERVICE BULLETIN, issued on the date i ndicated at the foot of the page:

- If there is no PR sealing compound on any of the lower parts of the MGB servo-control anchoring

fittings:
. leave as is, . Return the helicopter to flight condi tion in compliance with paragraph 2.B.4.

- If there is a bead of PR sealing compound on the lower part of at least one MGB

servo-control anchoring fitting:

. Contact the Customer Service Technical Support O perations Department (STVM) to inform it that

you have discovered a bead of PR sealing compound on the lower part of the attachment fittings, by: Tel: +33 (0)4.42.85.99.67 Fax: +33 (0)4.42.85.99.66. Email : Dyncomp.technica l-support@eurocopter.com

. Comply with paragraph 2.B.3. (See NOTE 3 of paragraph 1)

Or
. Leave as is and, . Return the helicopter to flight condi tion in compliance with paragraph 2.B.4.

then:

- Comply with paragraph 2.B.3. according to the conditions specified in paragraphs 1.E.2.a.1.

or 1.E.2.a.2.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 4/14

2008.05.07 NOTE 2

For MGBs for which the history of the operating conditions cannot be traced back, comply with the instructions given in paragraph 1.E.2.a.1.

1.E.2.a.1. For MGBs installed since new or last complete overhaul, on helicopters that have been operated in one of the following operating conditions , regardless of the time spent:

- Helicopters based onboard ship and operated offshore - Helicopters operated less than 1 kilometer off the coast - Helicopters operated at low attitude (less than 1000 feet) over the sea

and a) which have logged less than 30 months since new or last complete overhaul:

- comply with paragraph 2.B.3. at the latest w hen the MGB reaches 33 months since new or last complete overhaul of the MGB:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. at the late st when the MGB reaches 33 months since new

or last complete overhaul of the MGB.

b) which have logged between 30 and 33 months since new or last complete overhaul:

- comply with paragraph 2.B.3. at the latest w hen the MGB reaches 33 months since new or last complete overhaul of the MGB:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. at the late st when the MGB reaches 33 months since new

or last complete overhaul of the MGB.

or

- comply with paragraph 2.B.3. within 3 mont hs following receipt of this ALERT SERVICE

BULLETIN without exceeding 55 flying hours:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. within 3 mont hs following receipt of this ALERT SERVICE

BULLETIN without exceeding 55 flying hours.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 5/14

2008.05.07 c) which have logged more than 33 months since new or last complete overhaul:

-comply with paragraph 2.B.3. within 3 months following receipt of this ALERT SERVICE BULLETIN without exceeding 55 flying hours:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: -comply with paragraph 2.B.3.b. within 3 mont hs following receipt of this ALERT SERVICE BULLETIN without exceeding 55 flying hours.

1.E.2.a.2. For MGBs which have never been installed since new or last complete overhaul, on helicopters that have been operated in one of the following operating conditions:

- Helicopters based onboard ship and operated offshore - Helicopters operated less than 1 kilometer off the coast - Helicopters operated at low attitude (less than 1000 feet) over the sea

and

a) which have logged less than 54 months since new or last complete overhaul:

- comply with paragraph 2.B.3. at the latest w hen the MGB reaches 60 months since new or last complete overhaul of the MGB:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. at the late st when the MGB reaches 60 months since new

or last complete overhaul of the MGB.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 6/14

2008.05.07 b) which have logged between 54 and 60 months since new or last complete overhaul:

- comply with paragraph 2.B.3. at the latest w hen the MGB reaches 60 months since new or last complete overhaul of the MGB:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. at the late st when the MGB reaches 60 months since new

or last complete overhaul of the MGB.

or

- comply with paragraph 2.B.3. within 6 mont hs following receipt of this ALERT SERVICE

BULLETIN without exceeding 110 flying hours:

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. within 6 mont hs following receipt of this ALERT SERVICE

BULLETIN without exceeding 110 flying hours.

c) which have logged more than 60 months since new or last complete overhaul:

- comply with paragraph 2.B.3. within 6 mont hs following receipt of this ALERT SERVICE

BULLETIN without exceeding 110 flying hours.

. If there is no corrosion on the lower parts of the MGB servo-control anchoring fittings:

- comply with paragraph 2.B.3.a.

. If there is corrosion on at least one of the lo wer parts of the MGB servo-control anchoring

fittings: - comply with paragraph 2.B.3.b. within 6 mont hs following receipt of this ALERT SERVICE

BULLETIN without exceeding 110 flying hours.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 7/14

2008.05.07 1.E.2.b. Non-installed equipment: Before installing a MGB on a helicopter, comply with the instructions given in paragraph 2.B.2., and if there is PR sealing compound, comply with the instructions given in paragraph 2.B.3.



### NOTE 3

The time limits specified above are maximum time limits enabling operators to detect any corrosion before it affects the integrity of the fitting/casing attachment. However, we recommend that you remove the PR sealing compound in compliance with paragraph 2.B.3. as soon as possible, in order to limit the risk of corrosion occurring in this area and thus avoid replacing the MGB.



### 1.F. APPROVAL

Approval is limited to civil version helicopter s subject to an Airworthiness Certificate.

The technical information contained in th is ALERT SERVICE BULLETIN was approved on May 06, 2008 under the authority of EASA De sign Organization Approval No. 21J.056.



### 1.G. MANPOWER

Qualification: Mechanic. Time for the operations: For compliance with par agraphs 2.B.1., 2.B.2. and 2.B.4.: Approximately

30 minutes. For compliance with paragraphs 2.B.1., 2.B.3. and 2.B.4.: 1 to 17 hours, depending on the results of the check fo r absence of corrosion on the lower parts of the anchoring fittings.



### 1.H. WEIGHT AND BALANCE

Not applicable.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 8/14

2008.05.07 1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.



### 1.J. SOFTWARE MODIFICATION EMBODIMENT STATE

Not applicable.



### 1.K. REFERENCES

Standard Practices Manual (MTC) Work Cards:

- 20.04.04

- 20.04.05

- 20.05.01



### 1.L. OTHER DOCUMENTS CONCERNED

Not applicable.



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

Not applicable.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 9/14

2008.05.07 

### 2. ACCOMPLISHMENT INSTRUCTIONS

2.A. GENERAL

Not applicable.



### 2.B. OPERATIONAL PROCEDURE

2.B.1. Preliminary steps

- Install the equipment providing access to the MGB. - Remove the cowling providing access to the MGB.

2.B.2. Check all the lower parts of t he MGB servo-control anchoring fittings, in order to make sure that there is no PR sealing compound

As per Figure 1 :

- Check all the lower parts of the MGB servo-control anchoring fittings using a lamp or a dentist’s mirror, in order to make sure that there is no PR sealing compound.

Interpretation of the results :

a) If there is no PR sealing compound on any of the lower parts of the MGB servo-control anchoring fittings:

- Leave as is. - Return the helicopter to flight condi tion in compliance with paragraph 2.B.4.

b) If there is a bead of PR sealing compound on the lower part of at least one MGB servocontrol anchoring fitting:

- Contact the Customer Service Technical Support Operations Department (STVM) to inform it

that you have discovered a bead of PR sealing compound on the lower part of the attachment fittings, by: Tel: +33 (0)4.42.85.99.67 Fax: +33 (0)4.42.85.99.66. Email : Dyncomp.technica l-support@eurocopter.com

- Comply with paragraph 2.B.3.

Or - Leave as is and return the helicopter to flight configuration in compliance with paragraph 2.B.4.,

then: - Comply with paragraph 2.B.3. according to the conditions specified in paragraphs 1.E.2.a.1.

or 1.E.2.a.2.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 10/14

2008.05.07 2.B.3. Check to make sure that there is no corrosi on on the lower parts of the MGB servo-control anchoring fittings

As per Figure 1 :

- Remove the bead of PR sealing compound from the lo wer part of the servo-control anchoring fitting(s)

concerned.



### NOTE 1

There are different procedures for removing the bead of PR sealing compound. The procedures applied by EUROCOPTER to facilitate

removal are described below:

Use of a bronze knife or a plexiglas spatula: - Carefully cut the bead of PR sealing compound from the two zones

identified by (xxx) as shown on Figure 1 (zones located in the area of the hole for the lower bolt attaching the fitting). - Pull the bead of PR sealing compound gently from the cutting to

prevent it from tearing.

Use of plastic milling cutters: Designation: 50 mm diameter radial scoring disk – SR

Part number: 30097

Manufacturer: 3M, St Paul, MN 55144-1000, USA 3M, France Construction et Maintenance Aéronautique Bd de l'Oise 95006 Cergy Pontoise Cedex, France - Protect the adjacent areas from PR particle ejections. - Machine the bead of PR sealing compound with plastic milling

cutters. You must stack several (at least 3) plastic milling cutters. - Remove the PR sealing compound residues using a plexiglas

spatula or a bronze knife.

Then:

- Visually check using a lamp and a dentist’s mirror t hat there is no corrosion in the lower area of the

Main Gearbox casing, between the two servo- control anchoring fitting attachment ribs.

Interpretation of the results:

a) If there is no corrosion in the lower area of the Main Gearbox casing, between the two servo-control anchoring fitting attachment ribs: : - If necessary, touch up protective treatment as per MTC Work Cards 20.04.04 and 20.04.05. - If the bead of PR sealing compound in the areas referred to is damaged, renew it as per MTC

Work Card 20.05.01 (see Figure 1 ).

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 11/14

2008.05.07 THE BEAD OF PR SEALING COMPOUND MUST BE APPLIED TO THE

LATERAL EDGES AND TO THE UPPER PART OF THE SERVOCONTROL ANCHORING FITTINGS. NEVER APPLY A BEAD OF PR

SEALING COMPOUND TO THE LOWER PART OF THE SERVOCONTROL ANCHORING FITTINGS.

- Return the helicopter to flight configuration as per paragraph 2.B.4.

b) If there is corrosion on at least one MG B servo-control anchoring fitting lower part:

- Suspend flights immediately or at the latest at the time limits specified in paragraph 1.E.2.a.1.

or 1.E.2.a.2. - Comply with Repair Sheet FR 365-63-36-08 before resuming flights. - Return the helicopter to flight confi guration in compliance with paragraph 2.B.4.



### NOTE 2

Repair Sheet (FR) 365-63-36 -08 is available from the Customer Service Technical Support Operations Department (STVM) on the operator’s request: Tel: +33 (0)4.42.85.99.67 Fax: +33 (0)4.42.85.99.66 Email : Dyncomp.technica l-support@eurocopter.com

2.B.4. Final steps

Install the cowlings providing access to the MGB. Remove the equipment providing access to the MGB.



### 2.C. IDENTIFICATION

Record compliance with this ALERT SERVICE BU LLETIN on the log card of the MGB after having complied with paragraph 2.B.2., and where applicable: Record compliance with this ALERT SERVICE BU LLETIN on the log card of the MGB after having complied with paragraph 2.B.3.



### 2.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable. 

### CAUTION

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 12/14

2008.05.07 

### Lower part of the MGB servo-control anchoring fittings

**No bead of PR sealing compound Bead of PR sealing compound** 
**applied**
Figure 1 – Location of the anchoring fi ttings and beads of PR sealing compound 

### Servo-control anchoring
**fitting Location of the beads of** 
**PR sealing compound**

**Lower attachment bolt Lower attachment bolt**  **Locations of the**

**servo-control**
**anchoring fittings**

**Zones(XXX)**

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 13/14

2008.05.07 

### 3. MATERIAL INFORMATION

3.A. MATERIAL: COST – AVAILABILITY

Not applicable.



### 3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

Not applicable.



### 3.C. MATERIAL REQUIRED FOR EACH HELICOPTER / ENGINE / COMPONENT

The products required for compliance with the Tasks and / or Work Cards listed in paragraph 1.K., can be ordered from the INTERTURBINE company:

Website: http://www.itlogistics.de Telephone: +49.41.91.809.300

AOG: +49.41.91.809.444



### 3.D. MATERIAL REQUIRED FOR EACH SPARE PART

Not applicable.



### 3.E. RE-IDENTIFIED PARTS

Not applicable.



### 3.F. TOOLING: COST – AVAILABILITY

Not applicable.

### T.F.S. No. 00000449

Approved under EASA DOA No. 21J.056. Page 14/14

2008.05.07 3.G. PROCUREMENT CONDITIONS

Order the required quantity (unless otherwise specified)

from

EUROCOPTER Etablissement de Marignane

Direction Ventes et Relation Client

ECR

13725 MARIGNANE CEDEX

FRANCE


### NOTE 1

For ALERT SERVICE BULLETINS, order by:

Telex: HELICOP 410 969F Fax: +33 (0)4 42 85 99 96



### NOTE 2

On the purchase order, please specify the mode of transport, the destination and the serial numbers of the helicopters to be

modified.



### 4. APPENDIX

Not applicable.