### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 1/8

2007.02.15 EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE C EDEX F RANCE 

### CIVIL VERSION(S): E,F,F1,F2,N



# ALERT SERVICE BULLETIN

No. 64.00.04

SUBJECT : TAIL ROTOR

Improving the Tail Rotor Blade Trailing Edge Tab Security

Corresponds to Repair Sheet (FR) No. 283

REVISION No. DATE OF APPROVAL DATE OF ISSUE

Revision 0 On: October 25, 2004 2004.11.02 Revision 1 On: February 08, 2005 2005.02.10 Revision 2 On: February 14, 2007 2007.02.15

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 2/8

2007.02.15 

### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

For tail rotor blades P/N 355A120040. all dash numbers, with serial numbers from 8400 to 9224 inclusive, before embodiment of Repair Sheet (FR) No. 238 or Overhaul and Repair Manual (MRV) Work Card 64.10.00.872 (refer to the equipment log card (FME)),
and, for tail rotor blades P/N 355A120050. all dash numbers, with serial numbers from 8400 to 9224 inclusive, before embodiment of Repair Sheet (FR) No. 238 or Overhaul and Repair Manual (MRV) Work Card 64.10.00.872 (refer to the equipment log card (FME)).



### NOTE

Compliance with this ALERT SERVICE BULLETIN is not applicable to tail rotor blades with serial numbers from 8400 to 9224 inclusive that have been repaired in compliance with Repair Sheet (FR) No. 238 or as per Overhaul and Repair Manual (MRV) Work Card 64.10.00.872 (recorded on the equipment log card (FME)).



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.



### 1.C. REASON

To prevent the risk of losing the trailing edge tab of tail rotor blades.

Revision 0 of this ALERT SERVICE BULLETIN was t he subject of DGAC AS355 Airworthiness Directive No. 2004-176 (A).

Revision 1 of this ALERT SERVICE BULLETIN was t he subject of DGAC AS355 Airworthiness Directive No. 2004-176 (A) and provided additional information: - In EFFECTIVITY paragraph 1.A., concerning t he part numbers and serial numbers of the blades

concerned. - In paragraph 2.B.2., concerning the location of the rivet holes.

Revision 2 of this ALERT SERVICE BULLETIN, whic h will form the subject of an EASA Airworthiness Directive, introduces a deadline for compliance with this ALERT SERVICE BULLETIN in paragraph 1.E.2.b. for blades held as spares.

Revision 2 of this ALERT SERVICE BULLETIN does not affect compliance with Revision 1.



### 1.D. DESCRIPTION

Several cases of significant trailing edge tab debonding have been discovered on the tail rotor blades specified in paragraph 1.A.

TELEX INFORMATION No. 0000192, issued on July 12, 2004, provided a reminder of the current maintenance defined in the documentation, enabling oper ators to locate any debonding (visual check during the ALF-check (check after the last flight of the day) without exceeding 10 flying hours).

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 3/8

2007.02.15 In-service experience based on repor ts of debonding has shown that reduced security of the trailing edge tab due to debonding could lead to the loss of the tab if it is not monitored, and thus result in a significant

increase in the vibration level.

The results of the investigations conducted by EUROCOPTER revealed that reduced security of the bonding is due to the tab preparation process before bonding. The investigations made it possible to identif y the affected blades (listed in paragraph 1.A.). On some affected blades, the bonding security was re stored by approved workshops during repair. This repair in compliance with Repair Sheet (FR) No. 238 or as per Work Card 64.10.00.872 is recorded on the Equipment Log Card (FME) of the blade. Operators can increase the resistance of tail rotor blades to possible debonding by installing four additional rivets per blade (eight rivets per rotor) as a retrofit ac tion. This retrofit action is the subject of this ALERT

SERVICE BULLETIN



### 1.E. COMPLIANCE

EUROCOPTER renders compliance with this ALERT SERVICE BULLETIN, mandatory.

1.E.1. At the works

1.E.1.a. On aircraft: Prior to delivery, comply wi th paragraph 2.B. on the blades specified in paragraph 1.A.

1.E.1.b. On spares: Prior to installing t he blades specified in paragraph 1.A. on aircraft, comply with paragraph 2.B.

1.E.2. Retrofit action: By the operator.

1.E.2.a. On aircraft: On blades specified in paragraph 1.A., compliance with paragraph 2.B. was requir ed within 100 flying hours without exceeding 3 months, following receipt of Revision 1 of this ALERT SERVICE BULLETIN, issued on February 08, 2005.

1.E.2.b. On spares: Prior to installing the blades specified in paragraph 1.A. on an aircraft, and no later than April 30, 2007, comply with paragraph 2.B.



### 1.F. APPROVAL

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

The information or instructions relate to Repai r Sheet (FR) No. 283 approved on October 11, 2004 by the DGAC in accordance with article 10.3 of EC regulation No. 1592/2002.

The technical information contained in Revision 0 of this ALERT SERVICE BULLETIN was approved on October 25, 2004, under the authority of EASA Design Organisation Approval No. 21J.056.

The technical information contained in Revision 1 of this ALERT SERVICE BULLETIN was approved on February 08, 2005, under the authority of EASA Design Organisation Approval No. 21J.056.

The technical information contained in Revision 2 of this ALERT SERVICE BULLETIN was approved on February 14, 2007 under the authority of EASA Design Organisation Approval No. 21J.056.

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 4/8

2007.02.15 1.G. MANPOWER

Qualification: Mechanic.
Time: Approximately 1 hour per rotor.



### 1.H. WEIGHT AND BALANCE

Weight: No effect.

Moment: No effect.



### 1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.



### 1.J. SOFTWARE MODIFICATION EMBODIMENT STATE

Not applicable.



### 1.K. REFERENCES

Maintenance Manual (MET):

- Work Card 64.10.00.401. Standard Practices Manual (MTC):

- Work Card 20.02.05.401. Repair and Overhaul Manual (MRR):

- Work Card 64.10.00.764.



### 1.L. OTHER DOCUMENTS CONCERNED

Not applicable.



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

Not applicable.

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 5/8

2007.02.15 

### 2. ACCOMPLISHMENT INSTRUCTIONS

2.A. GENERAL

Not applicable.



### 2.B. OPERATIONAL PROCEDURE

2.B.1. Preliminary steps

Remove the tail rotor as per Work Card 64.10.00.401.

2.B.2. Installation of additional rivets on the trailing edge tab

As per Figure 1 - Lightly sand the zone to be drilled, using No. 80 then No. 220 abrasive paper. - Locate and drill 8 x 2.5 mm diameter holes (T):

. 4 holes (T) 12 mm from the existing rivets (E) and on the centerline of the exis ting rivets (E), then, . 4 holes (T) 24 mm from the existing rivets (E) and on the centerline of t he existing rivets (E).

- Deburr and clean the zone. - Install 8 rivets (1) on trailing edge tab (L) by means of riveting tongs fitted with riveting dies, as per

Work Card 20.02.05.401.



### NOTE

Any installation direction of the rivets is possible (pressure face or suction face).

- On completion of the riveting operation, check the bonding of the trailing edge tab:

. if no debonding is found, touch up paintwo rk as per Work Card 64.10.00.764,

. if debonding is found, return the tail rotor to an approved workshop for replacement of the trailing edge

tab (embodiment of Repair Sheet (FR) No. 238 or of Work Card 64.10.00.872) before resuming flights.

2.B.3. Final steps

Install the tail rotor as per Work Card 64.10.00.401.



### 2.C. IDENTIFICATION

Record compliance with this ALERT SERVICE BULLE TIN on the Equipment Log Card (FME) of the tail

rotor.



### 2.D. OPERATING AND MAINTENANCE INSTRUCTIONS

As per the Maintenance Program (PRE).

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 6/8

2007.02.15 Figure 1

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 7/8

2007.02.15 

### 3. MATERIAL INFORMATION

3.A. MATERIAL: COST - AVAILABILITY

For any information, contact the Customer Service Sales Department.



### 3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

Not applicable.



### 3.C. MATERIAL REQUIRED FOR EACH HELICOPTER, ENGINE/COMPONENTS

3.C.1. Component(s):

New Part Number Qty Item Key Word Former Part

Number Instructions
Disposition

21215DC2407J 8 1 Rivet

The materials identified by an asterisk "*" or required fo r 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

Phone: +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.

### ALERT SERVICE BULLETIN AS355

Approved under EASA DOA No. 21J.056. 

# 64.00.04 Page 8/8

2007.02.15 3.G. PROCUREMENT CONDITIONS

Order the required quantity (unless otherwise specified)

from

EUROCOPTER

Etablissement de La Courneuve Direction VENTES Service Client (S.V.) fax: 33(0)149344170

93123 LA COURNEUVE

FRANCE



### NOTE 1

For ALERT SERVICE BULLETINS, order by:

Telex: HELICOP 410 969F Fax + 33 (0) 1.49.34.41.70



### NOTE 2

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

aircraft to be modified.



### 4. APPENDIX

Not applicable.