SERVICE BULLETIN EC120 

Approved under DGAC DOA No. F.JA01 71-005 Page 1/18

 2004.05.14

 EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE CEDEX FRANCE CIVIL VERSION(S): B 

 

 

SERVICE BULLETIN 

No. 71-005 

SUBJECT : POWER PLANT 

 Spring-type engine suspension system

LIST OF APPROVED REVISIONS REVISION No. 0 APPROVED

 

Not applicable Date: May 13, 2004 

 
 SERVICE BULLETIN EC120 

Approved under DGAC DOA No. F.JA01 71-005 Page 2/18

 2004.05.14

1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters 

Helicopters type EC 120, version B. 

1.A.2. Component(s) affected 

Engine mount and flared coupling assembly, P/N C631A1101101. 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

- To suppress risks of engine suspension locking by installing a new type of damping system. 

- To cancel the visual periodical inspection requested in paragraph 1.C. of Alert Service Bulletin No. 05A003, 

Revision 2. 

1.D. DESCRIPTION 

The modification consists of: 

- Replacing the stack of upper spring washers by a helical compression spring. 

- Replacing the upper washer by a new part ensuring upper centering of the spring. 

- Installing a removable ball ring type engine deck feedthrough ensuring lower centering of the spring. 

- Cancelling the current sealing well and adding a sealing boot ensuring sealing of the engine/cargo 

compartment. 

- Removing the spacer. 

- Performing a die penetrant inspection of the flared coupling assembly, P/N C631A1101101. 
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1.E. APPLICATION 

Compliance with this Service Bulletin is at operator's/client's initiative. 

1.E.1. At the works 

1.E.1.a. On aircraft 

From serial number 1386. 

1.E.1.b. Spares 

Upon Customer's request. 

1.E.2. Retrofit action on the operator's site 

1.E.2.a. On aircraft 

By operators. 

1.E.2.b. Spares 

Before installation on aircraft, carry out die penetrant inspection as per paragraph 2.B.2.a. on flared 

couplings P/N C631A1101101 mounted on aircraft. 

1.F. APPROVAL 

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

1.F.1. Approval of modifications 

The information or instructions relate to Aircraft Modification Approval Form (FAM) No. A00570 issue 1 which 

was approved on March 08, 2004 under No. 2004/3445 by DGAC according to Article 10.3 of U.E. regulation 

1592/2002. 

1.F.2. Approval of the Service Bulletin 

The technical information contained in Revision 0 of this Service Bulletin No. 71-005 was approved on 

May 13, 2004 under the authority of DGAC Design Organisation Approval No. F.JA01. 

1.G. MANPOWER 

- Qualification: 1 mechanic. 

- Time: 14 hours approximately. 
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1.H. WEIGHT AND BALANCE 

- Weight: + 0.103 kg. 

- Moment / x: + 0.5 daN.m. 

1.I. EFFECT ON ELECTRIC LOADS 

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT STATE 

Not applicable. 

1.K. REFERENCES 

Aircraft Maintenance Manual (AMM): 

Tasks: 20-10-00,3-1, 20-10-00,3-2, 20-10-00,3-3, 20-10-00,3-4, 20-10-00,3-7, 20-10-00,3-10, 

20-10-00,3-14, 20-10-00,3-19, 20-10-00,3-27, 24-00-00,2-1, 24-00-00,3-1, 63-11-00,6-1, 

71-00-00,3-1, 71-41-00,4-1, 72-01-00,4-1, 72-01-00,4-2, 72-01-00,6-1. 

1.L. OTHER DOCUMENTS CONCERNED 

Illustrated Part Catalogue (IPC). 

Aircraft Maintenance Manual (AMM). 

Master Servicing Manual (MSM). 

1.M. INTERCHANGEABILITY OR MIXABILITY OF PARTS 

1.M.1. Interchangeability 

The new assembly is mounted in replacement of the former assembly (with spring washer stack). It is not 

interchangeable. 

1.M.2. Mixability 

- The new and former P/N's are not mixable. 

- The whole flared coupling P/N C631A1101101 which has already been used in flight with the washer-type 

suspension system must be checked by die penetrant method in the area of the suspension bar, as per 

AMM Task 20-10-00,3-19, before installation on the aircraft equipped with a spring-type engine suspension 

system. 
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2. ACCOMPLISHMENT INSTRUCTIONS 

2.A. GENERAL 

- Comply with general instructions on the power plant as per AMM Task 71-00-00,3-1. 

- Comply with general instructions on electrical generation as per AMM Task 24-00-00,3-1. 

- Implement and energise the electrical networks from the ground power supply as per AMM 

Task 24-00-00,2-1. 

- Checks after interventions on ARRIUS 2F engine as per AMM Task 72-01-00,6-1. 

- Bonding as per AMM Task 20-10-00,3-4. 

- Safetying as per AMM Task 20-10-00,3-1. 

- Torquing as per AMM Task 20-10-00,3-2. 

- MASTINOX sealant application method as per AMM Task 20-10-00,3-3. 

- Sealant application method as per AMM Task 20-10-00,3-14. 

- Alodine application method as per AMM Task 20-10-00,3-7. 

- Paint primer application method as per AMM Task 20-10-00,3-10. 

- Rivet installation and replacement method as per AMM Task 20-10-00,3-27. 

- Die penetrant inspection method as per AMM Task 20-10-00,3-19. 

- Detailed check of flared coupling assembly as per AMM Task 63-11-00,6-1. 

2.B. OPERATIONAL PROCEDURE 

CAUTION 

BEFORE ANY INTERVENTION ON THE POWER PLANT, 

READ THE GENERAL INSTRUCTIONS AS PER 

TASK 71-00-00,3-1 (AMM). 

2.B.1. Preliminary steps 

- Implement suitable access means. 

- Disconnect the electrical power supply sources as per AMM Task 24-00-00,2-1. 

2.B.2. Replacement of the spring-type engine suspension system (Figures 1, 2, 3 and 4) 

2.B.2.a. Preliminary steps (Figures 1 and 2) 

As per Figure 1: 

- Remove Arrius 2F engine as per AMM Task 72-01-00,4-1. 

- Remove engine mount fitting (y) as per AMM Task 71-41-00,4-1. 

- Scrap special washer (n), special bolt (o), spacer (p), washer (r) and spring washers (s). 

- Parts (a), (b), (c), (d), (e), (q), (t) are to be replaced systematically as per AMM Task 71-41-00,4-1. 

As per Figure 2: 

- Carry out detailed check of flared coupling (a) as per AMM Task 63-11-00,6-1. 

- Carry out die penetrant inspection of flared coupling (a) in external (A) and internal (B) areas as per AMM 

Task 20-10-00,3-19. 

- Flared coupling (a) will be replaced if crack is found.
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2.B.2.b. Installation of the new deck attachment system (Figures 3 and 4) 

As per Figure 3: 

- Remove fitting (z) and blank holes (B) with rivets (3) as per AMM Task 20-10-00,3-27, and protect with 

sealant (15). 

- Scrap fitting (z). 

NOTE 1

If rivet (3) drilling diameter exceeds 4.2, it is acceptable to fit 

repair rivets ASNA0078E505X. 

- Drill 8 holes on engine deck with tooling (Y) as per Figure 3: 

• 3 holes (C), countersunk on both sides. 

• 3 holes (D), counterbored to match beam (m). 

• 1 hole (E), chamfered as per detail (A) and counterbored and protected as per AMM Task 

20-10-00,3-7 and 20-10-00,3-10. 

• 1 hole (F), protected as per AMM Tasks 20-10-00,3-7 and 20-10-00,3-10. 

As per Figures 3 and 4: 

- Offer up and install reinforcement plate assy (1) with rivets (5) after interlaying sealant (15) as per AMM 

Task 20-10-00,3-14 on all faces in contact. 

- Offer up and secure dish (2) with rivets (4) after interlaying sealant (15) as per AMM Task 20-10-00,3-14 

on all faces in contact. 

2.B.2.c. Installation of engine mount fitting (y) (Figure 4) 

- Offer up and install cross beam (8) with bolt (9) and washer (10). 

- Torque as per AMM Task 20-10-00,3-2. 

NOTE 2

When installing washers (t), interlay grease (16) between 

each washer. 

- Offer up and install bolt (7), equipped with 3 spring washers (t) and seal (q) and maintain the assembley 

through engine deck. 

- Onto bolt (7), fit spring (13), centering washer (6) and sealing boot (14). 

- Onto bolt (7), fit hinge nut (f). 
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- Offer up and install washer (e), nut (d), and tighten to torque. 

- Safety with pin (c) as per AMM Task 20-10-00,3-1. 

- Install clamps (11) and (12) on boot (14) and tighten as per AMM Task 20-10-00,3-2. 

- Offer up LH support arm (g) and RH support arm (h), LH square (i) and RH square (j). 

NOTE 3

Check parallelism of support arms (g) and (h) with engine 

fittings (u), before tightening bolts (a) to torque. 

- After bonding as per AMM Task 20-10-00,3-4, offer up LH (i) and RH (j) squares with washers (b), 

bonding braid (l) and bolts (a), after interlaying sealant (18) between the parts in contact, as per 

AMM Task 20-10-00,3-3. 

- Reinstall engine as per AMM Task 72-01-00,4-2. 

- Tighten bolts (a) to torque and safety with lockwire (17) as per AMM Task 20-10-00,3-1. 

- Apply sealing bead with sealant (15) around squares (i) and (j), and coat bolt heads (a) as per 

AMM Task 20-10-00,3-14. 

2.B.3. Functional tests 

Carry out checks after intervention on engine as per AMM Task 72-01-00,6-1. 

2.B.4. Final steps 

- Remove the access means. 

- De-energize the electrical system of the helicopter as per AMM Task 24-00-00,2-1. 

- Restore the aircraft to flight condition. 

2.B.5. Spare parts 

2.B.5.a. Retrofitting of spare part stocks 

Not applicable. 

2.B.5.b. Replacement of spare part stocks 

Check flared couplings P/N C631A1101101 by die penetrant inspection method as per 

AMM Task 20-10-00,3-19. 
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2.C. IDENTIFICATION 

Record compliance with this Service Bulletin Revision 0 in the aircraft documents. 

Record embodiment of this Service Bulletin in the flared coupling log card (FME). 

2.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

2.D.1. Operating instruction(s) 

Not applicable. 

2.D.2. Maintenance instruction(s) 

For flared coupling assemblies P/N C631A1101101 which have already been used in flight with a engine 

suspension system before Service Bulletin No. 71-005, the retrofitting of the new spring-type suspension 

system allows exoneration from visual checks required at paragraph 1.C. of Alert Service Bulletin 

No. 05A003, Revision 2, subject to a possible crack detection in the area of the suspension bar (no crack 

admissible), by die penetrant inspection method as per AMM Task 20-10-00,3-19, before clearing the aircraft 

for flight. 
 SERVICE BULLETIN EC120 

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Figure 2
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Figure 3
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3. MATERIAL INFORMATION 

3.A. MATERIAL: COST - AVAILABILITY 

For all information, contact the Customer Support Sales Department. 

3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT 

Not applicable. 

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

3.C.1. Kit or component(s) to be ordered 

New P/N (in MPN) Qty Item Key word Former P/N Instructions 

Disposition 

 

C008A153306871 Kit including: 

C533A7190101 1 1 Plate, reinforcement, assy 

C533A7190202 1 2 Dish 

ASNA0078E504 4 3 Rivet 

ECS2151DXJ3206 3 4 Rivet 

ECS2152DXJ3210 3 5 Rivet 

C714A1112201 1 6 Washer, centering 

C714A1112202 1 7 Bolt, special 

C714A1112203 1 8 Cross beam 

22125BC050020L 1 9 Bolt 

23111AG050LE 1 10 Washer 

ASNA0033-090 1 11 Clamp 

ASNA0033-045 1 12 Clamp 

7050A3710013 1 13 Spring 

706A34-560-017 1 14 Boot, sealing 

3.C.2. Items to be ordered separately 

As per Tasks mentioned in the previous Service Bulletin and: 

New P/N (in MPN) Qty Item Key word Former P/N Instructions 

Disposition 

 

EN3628-1 A/R 17 Lockwire 
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3.C.3. Ingredient to be ordered separately 

As per Tasks mentioned in this Service Bulletin and: 

New P/N (in MPN) Qty Item Key word Former P/N Instructions 

Disposition 

 

ASN42112PF A/R 15 Sealant 

AIR 4222 A/R 16 Grease 

MASTINOX 6856 K A/R 18 MASTINOX sealant 

3.C.4. Material delivered by the customer 

Not applicable. 

3.C.5. Tooling 

As per Tasks mentioned in this Service Bulletin and: 

New P/N Qty Item Key word Former P/N Instructions 

Disposition 

 

4801C008A153306800 1 Y Drilling tool 

3.D. MATERIAL REQUIRED FOR EACH SPARE PART 

3.D.1. Kit to be ordered 

Not applicable. 

3.E. RE-IDENTIFIED PARTS 

Not applicable. 

3.F. TOOLING: COST - AVAILABILITY 

For all information as regards tooling renting, contact the Customer Support Sales Department. 
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3.G. PROCUREMENT CONDITIONS 

3.G.1. Material 

Order the required quantity 

from 

EUROCOPTER 

Etablissement de Marignane 

Direction VENTES Service Client 

S.V. 

13725 MARIGNANE CEDEX 

FRANCE 

NOTE

On the purchase order, please specify the mode of transport, 

the destination and the serial numbers of the aircraft to be 

modified. 

3.G.2. Ingredients 

The ingredients listed in this Service Bulletin and in the reference documents can be ordered from the 

INTERTURBINE company: 

Website : http://www.itlogistics.de

Telephone : +49.41.91.809.300 

AOG : +49.41.91.809.444 
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4. APPENDIX 

Not applicable.