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 CEDEX FRANCE 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 

 

 
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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 the subject of DGAC AS355 Airworthiness Directive 

No. 2004-176 (A). 

Revision 1 of this ALERT SERVICE BULLETIN was the subject of DGAC AS355 Airworthiness Directive 

No. 2004-176 (A) and provided additional information: 

- In EFFECTIVITY paragraph 1.A., concerning the 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, which 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 operators 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

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In-service experience based on reports 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 identify the affected blades (listed in paragraph 1.A.).

On some affected blades, the bonding security was restored 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 action. 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 with paragraph 2.B. on the blades specified in paragraph 1.A. 

1.E.1.b. On spares: Prior to installing the 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 required 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 helicopters subject to an Airworthiness Certificate. 

The information or instructions relate to Repair 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 

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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. 
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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 existing rivets (E), then, 

. 4 holes (T) 24 mm from the existing rivets (E) and on the centerline of the 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 paintwork 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 BULLETIN 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 

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Figure 1 
 ALERT SERVICE BULLETIN AS355 

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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 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

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. 
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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.