ASB No. EC225-05A031 

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 Civil version(s): LP 

 

ALERT SERVICE BULLETIN 

SUBJECT: TIME LIMITS - MAINTENANCE CHECKS 

Check of tail rotor control turnbuckle 

 ATA: 67 Rotor Flight Controls 

Revision No. Date of issue 

Revision 0 2013-03-14 

Revision 1 2013-06-05 

Summary: 

The purpose of this ALERT SERVICE BULLETIN is to carry out a visual check for absence of corrosion or crack(s) 

on the tail rotor control turnbuckles. 

Reason for last Revision: 

The purpose of Revision 1 of this ALERT SERVICE BULLETIN is to specify that the replacement of the turnbuckle 

related to external corrosion of less than or equal to 0.3 mm is carried out within 6 months following the last 

compliance with paragraph 3.B.2.c of this ALERT SERVICE BULLETIN. 

Compliance: 

Compliance with this ALERT SERVICE BULLETIN is mandatory. 

For the attention of 
 

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1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/installed equipment 

All EC225 helicopters equipped with turnbuckles P/N 330A27-5031-20. 

1.A.2. Non-installed equipment 

On turnbuckles P/N 330A27-5031-20. 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

Revision 0: 

EUROCOPTER has been informed of the rupture of one of the tail rotor control turnbuckles due to corrosion 

damage. The damage was discovered during a flight control check after a MGB replacement. Investigation 

revealed that missing Mastinox sealant between the turnbuckle tappings and end-fittings led to formation of 

galvanic corrosion. 

In case of corrosion, tail rotor control turnbuckles may break and lead to loss of tail rotor control on the 

helicopter. In order to prevent a similar occurrence, EUROCOPTER makes it mandatory to check all the tail 

rotor control turnbuckles to make sure there is no corrosion or crack. 

In addition, EUROCOPTER makes the visual check on the turnbuckles every 12 months mandatory. 

Revision 1: 

The purpose of Revision 1 of this ALERT SERVICE BULLETIN is to specify that the replacement of the 

turnbuckle related to external corrosion of less than or equal to 0.3 mm is carried out within 6 months 

following the last compliance with paragraph 3.B.2.c of this ALERT SERVICE BULLETIN. 

Revision 1 of this ALERT SERVICE BULLETIN does not affect compliance with Revision 0. 

1.D. DESCRIPTION 

This ALERT SERVICE BULLETIN consists of: 

- A visual check on all tail rotor control turnbuckles to make sure there is no corrosion or crack. 
 

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1.E. COMPLIANCE 

1.E.1. Compliance at the works 

Helicopters/installed equipment: 

Not applicable. 

 Non-installed equipment: 

Not applicable. 

1.E.2. Compliance in service 

 Helicopters/installed equipment: 

1) For helicopters delivered before 01/03/2013: 

 Comply with paragraphs 3.A., 3.B.1. and 3.B.2.a. of this ALERT SERVICE BULLETIN, within 110 flying hours 

or no later than within 3 months from receipt of this ALERT SERVICE BULLETIN Revision 0, issued on the 

date mentioned in the page footer. 

 Following compliance with paragraph 3.B.2.a., interpret the results for each of the two turnbuckles: 

- If there are cracks or corrosion, replace the turnbuckle as per paragraph 3.B.2.d. before resuming 

flights. 

- If there are no cracks and no corrosion, comply with paragraph 3.B.2.b.1. 

 Following compliance with paragraph 3.B.2.b.1., interpret the results: 

- If there are cracks, replace the turnbuckle as per paragraph 3.B.2.d. before resuming flights. 

- If there are no cracks and no corrosion, reinstall the turnbuckle as per paragraph 3.B.3. before resuming 

flights.

- If there are no cracks but corrosion is found, comply with paragraph 3.B.2.b.2. 

 Following compliance with paragraph 3.B.2.b.2., interpret the results: 

- If there is corrosion to a depth of over 0.3 mm. replace the turnbuckle as per paragraph 3.B.2.d. before 

resuming flights. 

- If there is corrosion to a depth less than, or equal to 0.3 mm: 

. Carry out corrosion treatment as per paragraph 3.B.2.c. 

. Reinstall the turnbuckle as per paragraph 3.B.3. before resuming flights. 

. Replace the turnbuckle as per paragraph 3.B.2.d. within 6 months following the last compliance with 

paragraph 3.B.2.c. of this ALERT SERVICE BULLETIN. 

NOTE 

A flow chart describing compliance with paragraph 3. and used 

to interpret the results is also available in Appendix 1. 

 Then, 

 Comply with paragraph 3. at intervals not exceeding 12 months. 

2) For helicopters delivered on or after 01/03/2013: 

 Comply with paragraph 3. at intervals not exceeding 12 months. 
 

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 Non-installed equipment: 

- For new tunbuckles or turnbuckles which have never been installed, no action is required. 

- For turnbuckles which have already been installed, comply with paragraphs 3.A. and 3.B.2.a. before 

installation or no later than within 12 months from receipt of this ALERT SERVICE BULLETIN Revision 0, 

issued on the date mentioned in the page footer. 

Then, interpret the results in the same manner as for installed equipment. 

1.F. APPROVAL 

 Approval of modifications: 

Not applicable. 

 Approval of this document: 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved 

on March 14, 2013 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 ALERT SERVICE BULLETIN Revision 0 was approved 

on March 14, 2013 under the prerogatives of the recognition of design capability FRA21J-002-DGA for 

French Government helicopters. 

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

on June 05, 2013 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 ALERT SERVICE BULLETIN Revision 1 was approved 

on June 05, 2013 under the prerogatives of the recognition of design capability FRA21J-002-DGA for French 

Government helicopters. 

1.G. MANPOWER 

Qualification: 

For compliance with this ALERT SERVICE BULLETIN: 

1 Mechanical Technician. 

Time for the operations: 

4 hours. 

Estimated helicopter grounding time: 

4 hours. 

1.H. WEIGHT AND BALANCE 

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS 

Not applicable. 
 

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1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD 

Not applicable. 

1.K. REFERENCES 

The following documents are required for compliance with this ALERT SERVICE BULLETIN: 

Aircraft Maintenance Manual (MMA): 

67-00-00-611 General Instructions 

67-22-00-061 Control Cables Removal - Installation 

Standard Practices Manual (MTC): 

20.02.06.408 Safetying Turnbuckles 

20.04.03.401 General Method for Reconditioning Corroded Metal Surfaces 

20.04.04.403 Touch-up of protective treatment with Alodine 1200 

20.04.05.402 Use of EPOXY primer P05 - P20 and P50

1.L. DOCUMENTS AFFECTED 

CAUTION 

 

THE USER OF THIS ALERT SERVICE BULLETIN 

MUST ENSURE THAT ALL MAINTENANCE 

DOCUMENTS NECESSARY FOR THE 

MAINTENANCE OF THIS INSTALLATION IS 

AVAILABLE. OTHERWISE, IT IS THE 

RESPONSIBILITY OF THE USER TO OBTAIN 

DOCUMENTS FROM THEIR USUAL EUROCOPTER 

CONTACT. 

Documents to be updated: 

The technical information given in this ALERT SERVICE BULLETIN will be integrated into the following 

manuals: MMA/MET. 

Documents already updated: 

Not applicable. 

1.M. INTERCHANGEABILITY OR MIXABILITY OF PARTS 

Not applicable. 
 

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2. MATERIAL INFORMATION 

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT 

For any information concerning price of kits and/or components, contact the Customer Relations and Sales 

Department of the EUROCOPTER network. 

EUROCOPTER 

Etablissement de Marignane 

Direction Ventes et Relations Client (ECR) 

13725 MARIGNANE CEDEX 

FRANCE 

NOTE 1 

On the purchase order, please always specify the mode of 

transport, the destination and the serial numbers of the aircraft 

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 

Components to be ordered for one helicopter or one assembly: 

Key Word Qty New 

P/N Item Former 

 P/N → Instruction 

 

 Turnbuckle 2* 330A27-5031-20 1 

* Depending on the condition as specified in paragraph 3.B with a maximum quantity of 2 per helicopter. 

 Material to be ordered separately: 

Key Word Qty New 

P/N Item Former 

 P/N → Instruction 

 

Locking Pin 4 651-91-4D54 2 Task 67-22-00-061 

Lock Washer 4 330A27-5030-20 3 Task 67-22-00-061 

Products to be ordered separately: 

Key Word Qty New 

P/N Item Former 

 P/N → Instruction 

 

MASTINOX sealant A/R 6856 K 4 

2.D. MATERIAL TO BE RETURNED 

Not applicable. 
 

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3. ACCOMPLISHMENT INSTRUCTIONS 

3.A. GENERAL 

Comply with the General Instructions as per MMA Task 67-00-00-611. 

3.B. OPERATIONAL PROCEDURE 

3.B.1. Preliminary steps 

Remove the 2 tail rotor control turnbuckles (a) as per Sub-Task 67-22-00-031-001 of MMA 

Task 67-22-00-061 (Figure 1). 

3.B.2. Procedure (Figure 1) 

3.B.2.a. Visual check for corrosion or crack(s) on tappings and middle hole (internal surface of turnbuckles) 

- Using an inspection light source, perform a visual check of the tappings and middle hole of the 

turnbuckles (a) for absence of corrosion or crack(s): 

Areas affected by corrosion may be dirty or show bulges and are covered with powdery deposit or 

whitish or reddish pits. 

- Interpret the results as per paragraph 1.E.2. 

3.B.2.b. External surface check 

3.B.2.b.1. Visual check for corrosion or crack(s) on external surface 

- Using an inspection light source, perform a visual check of the external surface of the turnbuckles (a) for 

absence of corrosion or crack(s): 

Areas affected by corrosion may be dirty or show bulges, the paint has usually faded and is covered with 

powdery deposit or whitish or reddish pits. 

- Interpret the results as per paragraph 1.E.2. 

3.B.2.b.2. Measurement of the corrosion depth 

- For each turnbuckle, if there is corrosion: 

. Sand the corroded surface until the corrosion is eliminated and apply the procedure defined in Work 

Card 20.04.03.401 (MTC) General method for reconditioning corroded metal surfaces. 

 . Gauge the damaged depth. 

- Interpret the results as per paragraph 1.E.2. 

3.B.2.c. Corrosion treatment on external surface 

- Perform corrosion treatment as per Work Card: 

20.04.03.401 General Method for Reconditioning Corroded Metal Surfaces 

20.04.04.403 Touch-up of protective treatment with Alodine 1200 

20.04.05.402 Use of EPOXY primer P05 - P20 and P50

3.B.2.d. Replacement of turnbuckle 

- Discard the damaged turnbuckle(s) (a). 

- Install the new turnbuckle(s) (1) as per Final steps paragraph 3.B.3. 
 

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3.B.3. Final steps 

- Visually check the general surface condition of the turnbuckle before installing it (scratches or damage to 

the paint) and, if necessary, touch up as per paragraph 3.B.2.c. 

CAUTION 

MAKE SURE END-FITTINGS AND INTERIOR OF 

THE TURNBUCKLE ARE COATED WITH 

MASTINOX SEALANT (4) BEFORE INSTALLATION 

OF THE TURNBUCKLE. 

- Install the tail rotor control turnbuckles (a) or (1) as per Sub-Task 67-22-00-431-001 of MMA 

Task 67-22-00-061 (Figure 1). 

- Safety the turnbuckles as per MTC Work Card 20.02.06.408. 

3.C. IDENTIFICATION 

Identification of this document: 

Record compliance with this document and the Revision number in the helicopter documents. 

3.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

 Operating instructions: 

Not applicable. 

 Maintenance instructions: 

EUROCOPTER makes compliance with paragraph 3. of this ALERT SERVICE BULLETIN mandatory, at 

intervals not exceeding 12 months. 
 

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Figure 1 

(1) or (a) 

(2)

(3)

(3)

(4)

(2)

(4)

(b)

(b)
 

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4. APPENDIX 

 

Presence of 

corrosion or crack(s) on the 

turnbuckle tappings or middle 

holes? 

Check for absence of corrosion or 

crack(s) on the external surface of the 

turnbuckles: Paragraph 3.B.2.b.1. 

Replace the turnbuckle 

before resuming flights: 

Paragraph 3.B.2.d. 

Check the depth of 

corrosion: 

Paragraph 3.B.2.b.2. 

Depth 

> 0.3 mm ? 

Reinstall the 

turnbuckle: 

Paragraph 3.B.3. 

Resume flights. 

- Carry out corrosion treatment: 

Paragraph 3.B.2.c. 

- Reinstall the turnbuckle: Paragraph 3.B.3. 

- Replace the turnbuckle within 6 months 

NO YES

NO 

NO

YES

YES

Check for absence of corrosion or 

crack(s) on the turnbuckle tappings 

and middle holes: Paragraph 3.B.2.a. 

Presence of crack(s) on the 

external surface of the 

turnbuckles? 

Periodic check at intervals not exceeding 12 months: 

Comply with Paragraph 3. 

Presence of corrosion on the 

external surface of the 

turnbuckles? 

YES

NO