ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 1/14

 2007.12.06

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

 EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE CEDEX FRANCE CIVIL VERSION(S): LP 

 

 ALERT SERVICE BULLETIN 

No. 05A002 

SUBJECT: TIME LIMITS - MAINTENANCE CHECKS

Check of the Attachment of Front and Rear MGB Suspension Bar 

Attaching Fittings

ATA: 53

REVISION No. DATE OF APPROVAL DATE OF ISSUE 

 

Revision 0 On: March 24, 2006 2006.03.28 

Revision 1 On: December 05, 2007 2007.12.06 

 

 

 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 2/14

 2007.12.06

1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/Installed equipment 

For bolts securing the attaching fittings of the front and rear MGB suspension bars. 

1.A.2. Non-installed equipment 

Not applicable. 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

To introduce a visual check of frames 3855 and 5295 if a significant loss of tightening torque load is found 

during the check of the tightening torques of the bolts that secure the front MGB bar attaching fitting, and the 

bolts that secure the rear MGB bar attaching fittings. 

The purpose of Revision 1 of this ALERT SERVICE BULLETIN is to increase the tightening torque checking 

interval for the front and rear MGB bar attaching fitting attachment bolts, from every 375 flying hours to every 

825 flying hours. 

Revision 1 of this ALERT SERVICE BULLETIN does not modify the operational procedure which is 

applicable since Revision 0 was issued. 

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

Revision 1 of this ALERT SERVICE BULLETIN will form the subject of an EASA Airworthiness Directive. 

1.D. DESCRIPTION 

Revision 0: 

Analysis of the tightening torque measurements that were to be taken on the helicopter fleet, in compliance 

with EC225 ALERT TELEX No. 53A002, has revealed some cases of tightening torque loss on the bolts that 

secure the rear MGB bar fittings. The measurement readings have shown that it is necessary to introduce, 

for EC225 helicopters, a periodic check and analysis of the tightening torque of the bolts that secure the front 

fitting. 

Significant loss of the tightening torque of the bolts that secure the MGB bar fittings can lead to a change in 

the loading mode of frames 3855 and 5295. Consequently, in the event of significant tightening torque loss 

of the bolts that secure the MGB bar attaching fittings, you must check that there is no crack in frames 3855 

and 5295, in the area of the MGB bar attaching fittings. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 3/14

 2007.12.06

The instructions given in EC225 ALERT TELEX No. 53A002 are canceled by EC225 ALERT SERVICE 

BULLETIN No. 53A002 issued on January 12, 2006 and are replaced with the instructions given in this 

ALERT SERVICE BULLETIN and in ALERT TELEX No. 05A001 issued on January 12, 2006. 

Revision 1: 

Following tests and calculations, the provisional tightening torque checking interval for the front and rear 

MGB bar attaching fitting attachment bolts is increased. These checks can now be made at intervals not 

exceeding 825 flying hours. 

This revision modifies the checking intervals currently specified in chapter 05-99 of the various Maintenance 

Programs. 

1.E. COMPLIANCE 

EUROCOPTER renders compliance with the measures defined in this ALERT SERVICE BULLETIN 

mandatory. 

1.E.1. Compliance at the works 

1.E.1.a. On helicopters/installed equipment: Comply with paragraph 1.E.2. 

1.E.1.b. On non-installed equipment: Not applicable. 

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

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

On helicopters which have been subject to compliance with Revision 0 of this ALERT SERVICE 

BULLETIN:

- Comply with paragraph 2.B. within 825 flying hours following last compliance with Revision 0, 

then, 

. comply with paragraph 2.B. at intervals not exceeding 825 flying hours. 

On helicopters which have not been subject to compliance with Revision 0 of this ALERT SERVICE 

BULLETIN:

- Comply with paragraph 2.B. at the next scheduled 750-flight hour inspection (i.e. “T” inspection) without 

exceeding 825 flying hours, 

then, 

. comply with paragraph 2.B. at intervals not exceeding 825 flying hours. 

1.E.2.b. On non-installed equipment: Not applicable. 

1.F. APPROVAL 

Approval is limited to civil version helicopters subject to an Airworthiness Certificate. 

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

on March 24, 2006 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 December 05, 2007 under the authority of EASA Design Organisation Approval No. 21J.056. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 4/14

 2007.12.06

1.G. MANPOWER 

Qualification: Mechanic. 

Time for the operations: Approximately 3 hours for the tightening torque check of the bolts that secure the 

front fitting. 

Approximately 2 hours for the tightening torque check of the bolts that secure the 

rear fittings. 

1.H. WEIGHT AND BALANCE 

Weight: None. 

Moment: None. 

1.I. EFFECT ON ELECTRICAL LOADS 

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT STATE 

Not applicable. 

1.K. REFERENCES 

Aircraft Maintenance Manual (MMA) Tasks: 53-26-00-062, 

53-26-00-212, 

71-00-00-051. 

Standard Practices Manual (MTC) Work Cards: 20.02.05.404, 

20.02.09.601. 

1.L. OTHER DOCUMENTS CONCERNED 

Maintenance Program (PRE) 05-99 will be updated subsequently. 

1.M. INTERCHANGEABILITY AND MIXABILITY OF PARTS 

Not applicable. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 5/14

 2007.12.06

2. ACCOMPLISHMENT INSTRUCTIONS 

2.A. GENERAL 

To avoid affecting correct measurement of the tightening torque, take care to correctly lock the 

head of bolt (b) or (h), from the inside of the cabin. 

In order to check that the bolt does not turn when measuring the tightening torque, first mark the 

associated position of the end of the threaded section of bolt (b) or (h) (in line with the pin hole 

axis) with respect to nut (a) or (g) and fitting (d) or (j) (see DETAIL A Figure 3). 

2.B. OPERATIONAL PROCEDURE 

2.B.1. Check of the tightening torque of the bolts that secure the front MGB bar attaching fitting 

- Remove the engines as per Subtask 71-00-00-021 of MMA Task 71.00.00.051. 

As per Figure 1: 

- Remove the trimmings and soundproofing mats from the area of frame 3855 and from the area of the 

attaching points of the front MGB bar attaching fitting. 

- Remove the sealing compound from the nuts (a). 

- Remove and scrap cotter pins (c). 

For the recommended tightening torque values, in accordance with the Figure in Appendix 1 and MMA 

Task 53-26-00-212: 

- Check the tightening torque of each nut (a), in accordance with MTC Work Card 20.02.05.404. 

- During the initial check, record each of the measured tightening torque values, once, in the table in 

Appendix 1. 

- Interpret the results of the check in accordance with paragraph 2.B.3. 

2.B.2. Check of the tightening torque of the bolts that secure the rear RH and LH MGB bar attaching fittings 

As per Figure 2: 

- Remove the trimmings and soundproofing mats from the area of frame 5295 and from the area of the 

attaching points of the mounting plates and attaching fittings of the rear RH and LH MGB bars. 

- If necessary, remove the TYRAP clamps, in order to separate the electrical harnesses. 

- Remove the sealing compound from the nuts (g). 

- Remove and scrap cotter pins (c). 

For the recommended tightening torque values, in accordance with MMA Task 53-26-00-212: 

- Check the tightening torque of each nut (g), in accordance with MTC Work Card 20.02.05.404. 

- Interpret the results in accordance with paragraph 2.B.3. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 6/14

 2007.12.06

2.B.3. Interpretation of the results of the checks in accordance with paragraph 2.B.1. and 2.B.2. 

As per Figures 1, 2 and 3. 

NOTE 1

If the position of the nut slots does not allow the cotter pin to be 

inserted within the tightening torque range, the nut must be 

replaced or you can reduce the thickness of washer (k) (by 0.1 

to 0.2 mm) by planishing it using No. 400-grit abrasive paper. 

Ensure perfect flatness of the washer (protect in accordance 

with MTC Work Card 20.04.04.404). 

2.B.3.a. Bolts securing the front MGB bar attaching fitting 

2.B.3.a.1. If the loss of the tightening torque load of nuts (a) is less than or equal to 20% of the recommended 

minimum tightening torque: 

- Remove the sealing compound from the nuts or screw heads on the front mounting plate (m). 

- Re-adjust the tightening torque of all the front mounting plate attaching nuts (n), as per MMA 

Task 53-26-00-062. 

- Torque tighten all the front fitting attachment nuts (a), as per MMA Task 53-26-00-212 and NOTE 1. 

- Safety the bolts (b) and nuts (a) with cotter pins (2). 

- Using a paint mark, identify the position of each nut (a) with respect to the fitting (d), and the position of 

the head of each bolt (b) with respect to frame 3855. 

- Run a bead of sealant round the nuts (a) and (n) and round the heads of the screws on the front 

mounting plate (m), as per MMA Tasks 53-26-00-212 and 53-26-00-062. 

- Return the helicopter to flight configuration as per paragraph 2.B.6. 

2.B.3.a.2. If the loss of the tightening torque load of at least one of the nuts (a) on the front fitting is more than 20% 

of the recommended minimum tightening torque: 

- Comply with paragraph 2.B.4. on all the front fitting attachment bolts (b) before resuming flights. 

2.B.3.b. Bolts securing the rear RH and LH MGB bar attaching fittings 

2.B.3.b.1. If the loss of the tightening torque load of nuts (g) is less than or equal to 20% of the recommended 

minimum tightening torque: 

- Remove the sealing compound from the nuts or screw heads on the rear RH and LH mounting plate. 

- Re-adjust the tightening torque of the nuts (f) on the rear RH and LH mounting plate (e), as per MMA 

Task 53-26-00-062. 

- Torque tighten all the attachment nuts (g) of the fittings, as per MMA Task 53-26-00-212 and NOTE 1. 

- Safety the bolts (h) and nuts (g) with cotter pins (2). 

- Using a paint mark, identify the position of each nut (g) with respect to the fitting (j), and the position of 

the head of each bolt (h) with respect to frame 5295. 

- Run a bead of sealant round the nuts (g) and (f) and round the heads of the screws that secure the 

rear mounting plates (e), as per MMA Tasks 53-26-00-212 and 53-26-00-062. 

- Return the helicopter to flight configuration, in compliance with paragraph 2.B.6. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 7/14

 2007.12.06

2.B.3.b.2. If the loss of the tightening torque load of at least one of the nuts (g) on the rear fittings is more than 20% 

of the recommended minimum tightening torque: 

- Comply with paragraph 2.B.5. on all the attachment bolts (h) that secure the rear fitting concerned, 

before resuming flights. 

2.B.4. Readjustment of the tightening torque of the screws that secure the front mounting plate and check for 

absence of cracks in the bolts (b) that secure the front MGB bar attaching fitting 

As per Figure 1: 

- Remove the sealing compound from the nuts or screw heads on the front mounting plate (m). 

- Re-adjust the tightening torque of all the nuts (n) on the front mounting plate, as per 

MMA Task 53-26-00-062. 

- Run a bead of sealant round the nuts (n) and round the heads of the screws that secure the front mounting 

plate (m), as per MMA Task 53-26-00-062. 

As per Figures 1 and 3: 

- If a tightening torque loss is detected on at least one of the four nuts (a) on attaching fitting (d), as specified 

in paragraph 2.B.3.a.2.: 

. Visually check that there is no crack in frame 3855, in the attachment area of attaching fitting (d) (see the 

photos shown on Figure 1). If in doubt, carry out a dye penetrant inspection as per MTC Work 

Card 20.02.09.601. 

- If there is a crack in frame 3855, 

. suspend flights and contact the Customer Service Technical Support Operations Department (STXS), 

by 

Tel.: +33 (0)4.42.85.99.29 

Fax: +33 (0)4.42.85.99.66, 

in order to define the steps to be taken. 

. Remove the four bolts (b), one by one, in order to carry out a dye penetrant inspection. 

. Carry out a dye penetrant inspection on the threaded bolt section as well as in the bolt head-to-plain 

section blending radius of the four bolts (b), as per MTC Work Card 20.02.09.601. 

- If no crack is found in the four bolts (b), you can re-install the four bolts (b), as per MMA 

Task 53-26-00-212 and NOTE 2. Torque tighten the nuts (a) to the tightening torque 

specified in MMA Task 53-26-00-212 and see NOTE 1. 

- If a crack is found in one of the four bolts (b), scrap and replace all four bolts (b) that secure the front 

fitting (d), with bolts (b), checked by dye penetrant inspection if the bolts are not new, or with new 

bolts (1), before resuming flights. Install the four bolts (1) or (b) as per MMA Task 53-26-00-212 and 

NOTE 2. Torque tighten the nuts (a) or (3) to the torque value specified in MMA Task 53-26-00-212 

and see NOTE 1. 

NOTE 2

Refer to Service Letter No. 1617-63-03. It defines the 

precautions that are to be taken when you re-install the 

bolts (b) or (h) and nuts (a) or (g) with MASTINOX. 

. Safety the bolts (b) or (1) and the nuts (a) or (3) with cotter pins (2). 

. Using a paint mark, identify the position of each nut (a) or (3) with respect to the fitting (d), and the position of 

the head of each bolt (b) or (1) with respect to frame 3855. 

. Run a bead of sealant round the nuts (a) or (3), as per MMA Task 53-26-00-212. 

. Return the helicopter to flight configuration, in accordance with paragraph 2.B.6. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 8/14

 2007.12.06

2.B.5. Readjustment of the tightening torque of the nuts of the screws that secure the rear mounting plates (e), and 

check for absence of cracks in the bolts (h) that secure the rear RH and LH MGB bar attaching fitting(s) 

As per Figure 2: 

- Remove the sealing compound from the nuts or screw heads on the rear RH and LH mounting plate (e). 

- Re-adjust the tightening torque of nuts (f) on the rear RH and LH mounting plate (e), as per MMA 

Task 53-26-00-062. 

- Run a bead of sealant round the nuts and round the heads of the screws that secure the rear RH and 

LH mounting plate (e), as per MMA Task 53-26-00-062. 

As per Figures 2 and 3: 

- If a tightening torque loss is detected on the nut(s) (g) on attaching fitting (j), as specified in 

paragraph 2.B.3.b.2.: 

. Visually check that there is no crack in frame 5295, in the attachment area of attaching fitting (j) (see 

the photos shown on Figure 2). If in doubt, carry out a dye penetrant inspection as per MTC Work 

Card 20.02.09.601. 

- If there is a crack in frame 5295, 

. suspend flights and contact the Customer Service Technical Support Operations Department (STXS), 

by 

Tel.: +33 (0)4.42.85.99.29 

Fax: +33 (0)4.42.85.99.66 

in order to define the steps to be taken. 

. Remove the 4 bolts (h), one by one, in order to carry out a dye penetrant inspection. 

. Carry out a dye penetrant inspection on the threaded bolt section as well as in the bolt head-to-plain 

section blending radius of the four bolts (h), as per MTC Work Card 20.02.09.601. 

- If no crack is found in the four bolts (h), you can re-install the four bolts (h), as per MMA 

Task 53-26-00-212 and NOTE 2. Torque tighten the nuts (g) to the tightening torque specified in MMA 

Task 53-26-00-212 and see NOTE 1. 

- If a crack is found in one of the four bolts (h), scrap and replace all four bolts (h) of the fitting concerned, 

with bolts (h), checked by dye penetrant inspection if the bolts are not new, or with new bolts (5), before 

resuming flights. Install the four bolts (5) or (h) as per MMA Task 53-26-00-212 and NOTE 2, and torque 

tighten the nuts (g) or (4) to the tightening torque specified in MMA Task 53-26-00-212 and see NOTE 1. 

- Safety the bolts (h) or (5) and the nuts (g) or (4) with cotter pins (2). 

- Using a paint mark, identify the position of each nut (g) or (4) with respect to the 

fitting (j), and the position of the head of each bolt (h) or (5) with respect to frame 5295. 

- Run a bead of sealant round the nuts (g) or (4), as per MMA Task 53-26-00-212. 

- Return the helicopter to flight configuration, in accordance with paragraph 2.B.6. 

2.B.6. Final steps 

- Re-install the TYRAP clamps if they were removed. 

- Install the trimmings and soundproofing mats in the area of frame 3855 and / or frame 5295. 

- Install the engines, as per Subtask 71-00-00-421 of MMA Task 71.00.00.051. 

2.C. IDENTIFICATION 

Record initial compliance with this ALERT SERVICE BULLETIN in the aircraft documents. 

2.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

Not applicable. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 9/14

 2007.12.06

Inspection zones on frame 3855, in the area of the bolts that secure the front attaching fitting

 

Figure 1 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 10/14

 2007.12.06

Inspection zone on frame 5295, in the area of the bolts that secure the rear attaching fitting

 

 

Figure 2 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 11/14

 2007.12.06

Figure 3 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 12/14

 2007.12.06

3. MATERIAL INFORMATION

3.A. MATERIAL: COST - AVAILABILITY 

For any information, contact the Sales and Customer Relations Department of the EUROCOPTER Network. 

3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT 

Not applicable. 

3.C. MATERIAL REQUIRED FOR EACH AIRCRAFT, ENGINE/COMPONENTS 

3.C.1. Component(s) 

New Part Number Qty Item Key Word Former Part Number Instructions 

Disposition 

 

332A22161320 or 21 A/R 1 Bolt, attachment, front 

23310CA020025 12 2 Cotter pin 

ASNA0045-120BCL A/R 3 Nut 

ASNA0045-100BCL A/R 4 Nut 

332A22161420 A/R 5 Bolt, attachment, rear 

3.C.2. Materials to be ordered separately 

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. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 13/14

 2007.12.06

3.F. TOOLING: COST - AVAILABILITY 

Not applicable. 

3.G. 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

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 aircraft to be 

modified. 
 ALERT SERVICE BULLETIN EC225 

Approved under EASA DOA No. 21J.056. 05A002 Page 14/14

 2007.12.06

4. APPENDIX 

Send the tightening torque measurement readings to the Technical Support Operations - Customer Service 

Department (STXS) at the EUROCOPTER/Marignane works, for analysis. 

Fax: 33 (0)4.42.85.99.66. 

Helicopter S/N: Flying hours logged: 

Tightening torque loads measured on the front fitting 

Nut 1 2 3 4 

daNm 

 

Lbf.in 

 

Appendix 1 

FERRURE AVANT 

FRONT FITTING