T.F.S. No. 00000486 

Approved under EASA DOA No. 21J.056 Page 1/15 

2008.12.01 This document is available on the Internet: www.eurocopter.com/techpub 

EUROCOPTER 

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE CEDEX FRANCE

EMERGENCY

ALERT SERVICE BULLETIN 

ECUREUIL NUMBER VERSIONS 

Civil: B-BA-BB-B1-B2-B3-D AS350 05.00.58 Military: L1 

Military: A2-C2-C3-U2 AS550 05.00.35 

SUBJECT: Time Limits – Maintenance Checks

Collective pitch lever locking stud

ATA: 67 

REVISION No. DATE OF APPROVAL DATE OF ISSUE 

 

Revision 0 On: 01/12/2008 01/12/2008 
T.F.S. No. 00000486 

Approved under EASA DOA No. 21J.056 Page 2/15 

2008.12.01

CAUTION 

THE INFORMATION AND INSTRUCTIONS 

CONTAINED IN THIS ALERT SERVICE BULLETIN 

ARE INTENDED FOR MAINTENANCE PERSONNEL. 

1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/installed equipment 

- Helicopters delivered before modification 073175, 

or 

- helicopters on which work has been carried out in service on the locking studs or on the collective 

pitch levers or on the locking strips, 

or 

- helicopters having been subject to compliance with Revision 0 or Revision 1 of Service Bulletins No. 

67.00.37 (AS350) or No. 67.00.19 (AS550), corresponding to modification 073237, 

or 

- helicopters with a serial number equal to: 3972-3973-3982-3987-4003-4023-4046-4050-4086-4120-

4122-4132-4143-4152-4172-4194-4259-4314-4324-4378-4392-4447-4452-4477-4489-4490-4501-

4523-4546-4560-4589-4594-4599-4632-4659-4666-4671. 

NOTE 1

Service Bulletins No. 67.00.37 and No. 67.00.19 correspond 

to modification 073237 which consists in replacing the 

collective pitch lever locking stud, which was initially made 

from light alloy, with a longer locking stud made from steel 

(see Figure 1). 

NOTE 2

The modification 073175 consists in replacing the original 

flexible locking strip with a rigid strip with hinged lower end 

and returned to the forward position by a spring. 

NOTE 3

Refer to the Aircraft Individual Inspection Record (RIC), the 

Log Cards (FM) or the aircraft logbook to identify the actual 

configuration of the helicopter. 

1.A.2. Non-installed equipment 

Not applicable. 
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2008.12.01

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

To ensure that there is a minimum clearance between the end of the locking stud and the locking 

strip to prevent untimely locking of the collective pitch lever. 

This ALERT SERVICE BULLETIN will form the subject of an EASA Airworthiness Directive. 

1.D. DESCRIPTION 

EUROCOPTER has introduced the modification 073237, mentioned in paragraph 1.A.1., which 

prevents wear of the locking stud and thus precludes the risk of untimely unlocking of the collective 

pitch lever during the starting phase. 

This modification has introduced a new locking stud which is longer than the previous one. 

For this reason, the clearance between the locking stud and the locking strip is reduced and in some 

cases it proves to be insufficient when the collective pitch lever is positioned on the "low pitch" stop. 

In fact, on a helicopter during an autorotation test in flight, it was found that the collective pitch lever 

rubbed against the locking strip in the "low pitch" position (low position). This rubbing is due to 

insufficient clearance and could result in untimely locking of the collective pitch lever. 

To preclude the risk of untimely locking, EUROCOPTER is introducing a mandatory measure to 

ensure a required minimum clearance and is providing a repair solution in case the clearance is 

insufficient. 

As a precautionary measure, this measure and repair if necessary are also extended to helicopters 

with locking studs pre-MOD 073237. 

1.E. COMPLIANCE 

EUROCOPTER renders compliance with this ALERT SERVICE BULLETIN mandatory.

1.E.1. Compliance at the works 

1.E.1.a. On helicopters: Not applicable. 

1.E.1.b. On non-installed equipment: Not applicable. 
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2008.12.01

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

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

- Comply with paragraph 2. during the ALF-check (check after the last flight of the day) following 

receipt of this ALERT SERVICE BULLETIN, issued on the date indicated at the bottom of the 

page, 

Then, 

- Comply with paragraph 2.B.2.a. or 2.B.3.a., according to the helicopter configuration: 

. each time the collective pitch lever, the locking stud or the locking strip is replaced, 

. each time the locking strip setting is readjusted, 

. at intervals not exceeding 660 hours or 2 years, the first limit reached is applicable. 

If a flight is necessary to ferry the helicopter to a repair station or a place where the 

maintenance can be performed in order to comply with paragraphs 2.B.2.b, 2.B.2.c and 

2.B.3.b., the flight is permitted with no passenger on board. 

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 given in this ALERT SERVICE BULLETIN was approved on 

December 1, 2008 under the authority of EASA Design Organisation Approval No. 21J.056. 

The information or instructions relate to change: MOD 350A088525 which was approved on 

November 21, 2008 under the authority of EASA Design Organisation Approval No. 21J.056. 

1.G. MANPOWER 

Qualification: 1 Mechanic 

Time for the operations: 10 minutes to comply with paragraph 2.B.2.a. or 2.B.3.a. 

 1 hour to comply with paragraph 2. except paragraph 2.B.2.a. or 2.B.3.a. 

1.H. WEIGHT AND BALANCE 

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS 

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD 

Not applicable. 
T.F.S. No. 00000486 

Approved under EASA DOA No. 21J.056 Page 5/15 

2008.12.01

1.K. REFERENCES 

Maintenance Manual (MET): 

- Work Card 67.10.00.501 

- Work Card 67.10.00.502 

Standard Practices Manual (MTC): 

- Work Card 20.02.05.404 

- Work Card 20.02.06.402 

- Work Card 20.04.04.404 

- Work Card 20.04.05.402 

- Work Card 20.08.05.103 

1.L. OTHER DOCUMENTS AFFECTED 

EUROCOPTER will modify the following document with respect to this ALERT SERVICE BULLETIN: 

MET. 

1.M. TOOLING AFFECTED 

Not applicable. 

1.N. INTERCHANGEABILITY OR MIXABILITY OF PARTS 

Not applicable. 
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2008.12.01

2. ACCOMPLISHMENT INSTRUCTIONS 

2.A. GENERAL 

Not applicable. 

2.B. OPERATIONAL PROCEDURE 

2.B.1. Preliminary steps 

Not applicable. 

2.B.2. Helicopters modified per modification 073237 

2.B.2.a. Measurement of the clearance between the end of locking stud (c) and strip (a) (Figure 2): 

- Move collective pitch lever (b) to the "low pitch" position (low position) without locking it on strip (a). 

- Measure clearance "J". 

- If clearance "J" is equal to or more than 3 mm, return the helicopter to flight configuration. 

- If clearance "J" is less than 3 mm, comply with paragraph 2.B.2.b. 

2.B.2.b. Interpretation of the results: 

For helicopters pre-modification 073175: 

- verify that the grommet in locking strip (a) is seated against the console: 

. if the grommet in locking strip (a) is seated against the console, comply with paragraph 2.B.2.c. 

. if the grommet in locking strip (a) is not seated against the console, restore the original profile of 

the locking strip: 

. mark the position of locking strip (a) on the console so that the locking strip can be re-installed 

at the same location, 

. remove the locking strip (remove the 2 screws and the 2 washers), 

. on a workbench, clamp the locking strip in a vice fitted with soft jaws,

. apply a load progressively to the locking strip in order to restore its original profile,

. remove the locking strip from the vice and install it on the console (fit the 2 screws and the 2 

washers), in the position marked previously, then once again measure clearance “J” as 

measured previously: 

. If clearance "J" is equal to or more than 3 mm, return the helicopter to flight configuration in 

compliance with paragraph 2.B.4., 

. If clearance "J" is less than 3 mm, comply with paragraph 2.B.2.c. 

CAUTION 

Replace locking strip (a) within a time limit of 

3 months if its original profile has been restored. 

For helicopters post-modification 073175: 

- comply with paragraph 2.B.2.c. 
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2.B.2.c. Adjusting the length of the collective pitch lever locking stud post-modification 073237 

 (Figures 3 and 4) 

- Remove and discard pin (d). 

- Cut and remove the lock-wire from the two screws (e). 

- Remove and retain the two screws (e). 

- If washers are fitted, remove and retain the two washers (f). 

- Remove locking stud (g). 

- File stud (g) to length as per Figure 4. 

- Break sharp edges with a 1 mm radius (R1). 

- Protect the reworked area with MAGICBLUER + P05 + P20 (4) as per MTC Work 

Cards 20.04.04.404 and 20.04.05.402. 

- Apply matt-black top coat paint (2). 

- Strike out the former part number of the locking stud and mark the new part number with white 

paint as per paragraph 2.C. and as per MTC Work Card 20.08.05.103. 

- Attach locking stud (g) to the collective pitch lever with: 

. pin (1), 

. the two screws (e) and two washers (f) if removed previously. 

- Torque tighten screws (e) as per MTC Work Card 20.02.05.404 then safety them with lock-wire (3) 

as per MTC Work Card 20.02.06.402. 

- Verify that clearance "J" is equal to or more than 3 mm as defined in paragraph 2.B.2.a. and return 

the helicopter to flight configuration in accordance with paragraph 2.B.4. 

2.B.3. Helicopters not modified per modification 073237 

2.B.3.a. Measurement of the clearance between the end of locking stud (c) and locking strip (a) (Figure 2): 

- Move collective pitch lever (b) to the "low pitch" position (low position) without locking it on strip (a). 

- Measure clearance "J". 

- If clearance "J" is equal to or more than 3 mm, return the helicopter to flight configuration. 

- If clearance "J" is less than 3 mm, comply with paragraph 2.B.3.b. 

2.B.3.b. Interpretation of the results: 

For helicopters pre-modification 073175: 

- verify that the grommet in locking strip (a) is seated against the console: 

. if the grommet in locking strip (a) is seated against the console, suspend flights and inform the 

Customer Service Technical Support Department (Département Support Technique du Service à 

la clientèle) in order to define the method to make the helicopter compliant: 

Fax: +33(0)4.42.85.99.66 

E-mail: Hydraulics.technical-support@eurocopter.com
T.F.S. No. 00000486 

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2008.12.01

. if the grommet in locking strip (a) is not seated against the console, restore the original profile of 

the locking strip: 

. mark the position of locking strip (a) on the console so that the locking strip can be re-installed 

at the same location, 

. remove the locking strip (remove the 2 screws and the 2 washers), 

. on a workbench, clamp the locking strip in a vice fitted with soft jaws,

. apply a load progressively to the locking strip in order to restore its original profile,

. remove the locking strip from the vice and install it on the console (fit the 2 screws and the 2 

washers), in the position marked previously, then once again measure clearance “J” as 

measured previously: 

. if clearance "J" is equal to or more than 3 mm, return the helicopter to flight configuration in 

compliance with paragraph 2.B.4., 

. if clearance "J" is less than 3 mm, suspend flights and inform the Customer Service Technical 

Support Department (Département Support Technique du Service à la clientèle) in order to 

define the method to make the helicopter compliant: 

 Fax: +33(0)4.42.85.99.66 

 E-mail: Hydraulics.technical-support@eurocopter.com

CAUTION 

Replace locking strip (a) within a time limit of 

3 months if its original profile has been restored. 

For helicopters post-modification 073175: 

. suspend flights and inform the Customer Service Technical Support Department (Département 

Support Technique du Service à la clientèle) in order to define the method to make the helicopter 

compliant: 

Fax: +33(0)4.42.85.99.66 

E-mail: Hydraulics.technical-support@eurocopter.com

2.B.4. Final steps 

- Check the adjustment of the locking strip as per the "Checking the adjustment" paragraph of: 

. MET Work Card 67.10.00.501 for helicopters without autopilot, 

. MET Work Card 67.10.00.502 for helicopters with autopilot. 

- If necessary, readjust the strip as per the "Adjustment of the LOW PITCH locking strip" paragraph 

of: 

. MET Work Card 67.10.00.501 for helicopters without autopilot, 

. MET Work Card 67.10.00.502 for helicopters with autopilot. 
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2.C. IDENTIFICATION 

Record first compliance with this ALERT SERVICE BULLETIN in the helicopter documents. 

Identify the new locking studs as per the Table below if compliance was ensured with paragraph 

2.B.2.c.: 

Key Word Former Part Number New Part Number Version 

Locking stud 350A27-3155-21 350A08-8525-25 B3-C3 

Locking stud 350A08-2363-20 350A08-8525-25 B3-C3 

Locking stud 350A27-3155-22 350A08-8525-26 B1-B2-BA-BB-B-D 

Locking stud 350A27-3155-23 350A08-8525-27 L1-A2-C2-U2 

2.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

Not applicable. 
T.F.S. No. 00000486 

Approved under EASA DOA No. 21J.056 Page 10/15 

2008.12.01

Figure 1: Modification 073237 
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Figure 2: Measuring clearance "J" 

J 

c 

a 

J 

a 

b 

c 

b 
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Figure 3: Removing/Installing the locking stud 
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 Versions B3-C3 Versions B1-B2-BA-BB-D-B 

 Versions L1-A2-C2-U2 

Figure 4: Adjusting the length of the locking stud 
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3. MATERIAL INFORMATION 

3.A. MATERIAL: PRICE AND AVAILABILITY 

Not applicable. 

3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT 

Not applicable. 

3.C. MATERIAL REQUIRED FOR EACH HELICOPTER/ENGINE/COMPONENT 

3.C.1. Kits or components to be ordered for one helicopter or one assembly 

Material P/N Qty Item Key Word Instructions 

 

NSA5319-05-012 1 1 Pin Replace 

350A27-3107-26 AR a Locking strip 

3.C.2. Material to be ordered separately 

Material P/N Qty Item Key Word Instructions 

 

GM2-99NOIR AR 2 Paint 

EN3628-0,5 AR 3 Lock-wire 

MAGICBLUER+P05+P20 AR 4 Protection 

The products necessary for compliance with the Work Cards listed in paragraph 1.K. can be ordered 

from the INTERTURBINE company: 

Website: http://www.itlogistics.de

Telephone: +49.41.91.809.300 

AOG : +49.41.91.809.444 

3.C.3. Tools 

Not applicable. 
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3.D. 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 

helicopters to be modified. 

4. APPENDIX 

Not applicable.