T.F.S. No. 00000338 

Approved under EASA DOA No. 21J.056 Page 1/16 

2006.11.23

EUROCOPTER 

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE CEDEX FRANCE

EMERGENCY

ALERT SERVICE BULLETIN 

DAUPHIN NUMBER VERSIONS 

Civil: N, N1, N2, N3 365 62.00.24 Military: F, Fs, Fi, K 

AA, MA, MB, SA, SB, 565 62.00.10 Military: UB 

Civil: G1 366 62.14 Military: GA 

365 65.45 Civil: C, C1, C2, C3 

SUBJECT: MAIN ROTOR 

Frequency Adapter with Ventilation Holes

Corresponds to MOD 0762C39

REVISION NUMBER DATE OF APPROVAL DATE OF ISSUE 

 

Revision 0 On: November 23, 2006 2006.11.23 
T.F.S. No. 00000338 

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2006.11.23

1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters / Installed equipment 

a) On helicopters with a main rotor head fitted with frequency adapters pre MOD 0762C39 (see NOTE 3) 

and operated in hot climatic conditions and/or tropical and damp atmosphere, see NOTE 1. 

Refer to the part numbers of frequency adapters pre MOD 0762C39 listed in paragraph 2.B.2.v. 

NOTE 1

1) The operating conditions of helicopters operated in 

tropical and damp atmospheric conditions are defined 

in the “GENERAL” chapter of the Maintenance 

Program (PRE). 

2) The operating conditions of helicopters operated in 

hot climatic conditions are defined as follows: 

- Helicopter operated in areas with high solar radiation 

temperatures above 40°C. 

b) On helicopters with a main rotor head fitted with frequency adapters post MOD 0762C39, 

 see NOTE 2. 

 Refer to the part numbers of frequency adapters post MOD 0762C39 listed in paragraph 2.B.2.v. 

NOTE 2

For helicopters with a main rotor head fitted with 

frequency adapters post MOD 0762C39, only the 

instructions in paragraph 1.E.2.a.2 of this ALERT 

SERVICE BULLETIN are applicable. 

NOTE 3

SA 366 GA helicopters modified per OP 62C36 

(modification equivalent to MOD 0762C39) are not 

concerned by the instructions in this ALERT SERVICE 

BULLETIN. 

1.A.2. Non-installed equipment 

On equipment designed to operate in hot climatic conditions and / or tropical and damp atmosphere: 

- On main rotor heads fitted with frequency adapters pre MOD 0762C39. 

- On frequency adapters pre MOD 0762C39. 

- On frequency adapter bushes pre MOD 0762C39 (non-drilled bushes). 
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1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

To reduce the operating temperature of the Starflex star arm end by improving the air flow, by locally 

drilling 4 holes in the frequency adapters and in the bushes that secure the bearing. 

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

1.D. DESCRIPTION 

On October 12, 2006, following some reports of deterioration and two reports of failure of Starflex star 

arm ends, EUROCOPTER issued ALERT SERVICE BULLETINS No. 05.00.51R1/AS365, 

05.00.21R1/AS565, 05.35R1/SA366 and 05.28R1/SA365, in order to render the monitoring of the integrity 

of the bush-to-star arm end attachment mandatory. At the same time, in order to identify the reason for 

these deteriorations, EUROCOPTER has conducted complementary analyses and tests which have 

revealed that temperature has a strong effect on the strength of this attachment and that this temperature 

can be reduced significantly by improving the air flow in this area. 

EUROCOPTER has defined modification 0762C39 which reduces the operating temperature in this area 

and thus improve the behavior of the Starflex star arm end. 

This modification can be embodied by Customers and consists in improving the air flow in this area by 

drilling two holes on both sides of the armature of the frequency adapter and in the bush that secures the 

bearing. 
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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: 

 MOD 0762C39 will be embodied from November 27, 2006. 

1.E.1.b. On non-installed equipment: 

 MOD 0762C39 will be embodied from February 1, 2007.

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

1.E.2.a. On helicopters / installed equipment used in hot climatic conditions and/or in tropical and damp 

atmosphere: 

1.E.2.a.1. On main rotor heads fitted with frequency adapters pre MOD 0762C39: 

- Comply with paragraphs 2.B.1. to 2.B.3. within 110 flying hours following receipt of this ALERT 

SERVICE BULLETIN, issued on the date indicated at the foot of the page. 

1.E.2.a.2. On main rotor heads fitted with frequency adapters post MOD 0762C39: 

- Comply with paragraph 2.B.6. every 10 flying hours. 

CAUTION 

EACH TIME A FREQUENCY ADAPTER OR FREQUENCY 

ADAPTER BUSH POST MOD 0762C39 IS INSTALLED, DO 

NOT FORGET TO FIT THE LOCKWIRE (5). 

1.E.2.b. On non-installed equipment 

 On equipment designed to operate in hot climatic conditions and/or in tropical and damp atmosphere: 

- On main rotor heads fitted with frequency adapters pre MOD 0762C39, comply with paragraph 2.B.2. 

of this ALERT SERVICE BULLETIN. 

- On frequency adapters pre MOD 0762C39, comply with paragraph 2.B.4. of this ALERT SERVICE 

BULLETIN. 

- On frequency adapter bushes pre MOD 0762C39 (non-drilled bushes), comply with paragraph 

2.B.5. of this ALERT SERVICE BULLETIN. 
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2006.11.23

1.F. APPROVAL 

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

The information or instructions relate to change: MOD 0762C39 which was approved on November 14, 

2006. 

The technical information given in this ALERT SERVICE BULLETIN was approved on 

November 23, 2006 under the authority of EASA Design Organisation Approval No. 21J.056. 

1.G. MANPOWER 

Qualification: Mechanic to comply with paragraphs 2.B.1. to 2.B.3. 

Time for the operations: Approximately 12 hours for one main rotor head. 

Time for Alodine 1200 and P05 paint application and drying: Approximately 4 hours. 

Qualification: Mechanic or flight crew to comply with paragraph 2.B.6. 

Time for the operations: Approximately 5 minutes. 

NOTE 4

Compliance with the instructions in paragraph 2.B.6. can be 

ensured by the flight crew if appropriately trained for this 

maintenance. 

1.H. WEIGHT AND BALANCE 

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS 

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT STATE 

Not applicable. 
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1.K. REFERENCES 

Maintenance Manual (MET) Work Cards: 53.50.00.401 - 62.10.00.401 - 62.20.00.402 

and 62.20.00.603. 

or 

53.50.401 – 65.11.401 – 65.14.402 and 65.14.604. 

Standard Practices Manual (MTC) Work Cards: 20.04.04.403 and 20.04.05.402. 

1.L. OTHER DOCUMENTS CONCERNED 

Maintenance Program (PRE). 

Maintenance Manual (MET). 

1.M. TOOLING CONCERNED 

Not applicable. 

1.N. INTERCHANGEABILITY AND MIXABILITY OF PARTS 

1.N.1. Interchangeability: Prohibited. 

1.N.2. Mixability: Frequency adapters post MOD 0762C39 cannot be combined with frequency adapters pre 

MOD 0762C39. 
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2. ACCOMPLISHMENT INSTRUCTIONS 

2.A. GENERAL 

The operational procedure in paragraph 2.B.2. is described for one frequency adapter and must be 

applied to the four frequency adapters installed on the main rotor head. 

2.B. OPERATIONAL PROCEDURE 

2.B.1. Preliminary steps 

- Remove the MGB cowlings as per MET Work Card 53.50.00.401 or 53.50.401. 

- Remove the main rotor blades as per MET Work Card 62.10.00.401 or 65.11.401. 

2.B.2. Embodying MOD 0762C39 on the frequency adapters and adapter bushes 

a) Remove the frequency adapters from the blade attach beams, as per MET Work Card 62.20.00.402 

 or 65.14.402. 

b) Identify each frequency adapter with respect to the sleeve from which it was removed. 

c) Remove the screws (2) and washers (3) to ease the marking of the position of the four holes 

 (Figure 1). 

d) On the frequency adapter (1), mark out the position of the four 8 mm diameter holes (two holes on the 

leading edge and two holes on the trailing edge, as shown on Figure 1). 

ON CERTAIN FREQUENCY ADAPTERS, WHEN 

DRILLING THE HOLES, THE “UP” MARKING OR THE 

SERIAL NUMBER AND THE DATE OF 

MANUFACTURE MAY BE DEFACED. IN THIS CASE, 

YOU MUST VIBRO-ETCH 

- THE "UP” MARKING IN AREA X (FIGURE 1), 

- THE SERIAL NUMBER AND THE DATE OF 

MANUFACTURE IN AREA Y (FIGURE 6). 

 (SIZE OF THE LETTERS: 2.5 TO 4 MM) 

e) Spot-drill the position of the four holes on the frequency adapter (1). 

CAUTION 
T.F.S. No. 00000338 

Approved under EASA DOA No. 21J.056 Page 8/16 

2006.11.23

Figure 1 

f) Fit the washers (3) and the screws (2) to hold the bush (4) in place during drilling 

(Figure 2). 

g) Mask the inside of the bush (4) with adhesive tape in order to protect the bearing from drilling chips 

(Figure 2). 

Figure 2 

4 

2 

3 
T.F.S. No. 00000338 

Approved under EASA DOA No. 21J.056 Page 9/16 

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NOTE 1

Adjust the drilling depth of the drill bit and turn the 

bearing to the inside of the frequency adapter, in order to 

avoid damaging the bearing with the protruding tip of the 

drill bit. 

Use drill bits compatible with “aluminum” or “steel”. Do 

not lubricate. 

h) Drill four 4 mm diameter pilot holes in the frequency adapter (1) and in the bush (4). 

i) Drill out the four 4 mm diameter pilot holes using an 8 mm drill bit (Figure 3). 

Figure 3 

j) Remove the adhesive tape from the frequency adapter (1) and remove any chips. 

k) Remove the screws (2), the washers (3) and the bush (4) from the frequency adapter (1) (Figure 2). 

4

1 
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l) Mask the bearing with adhesive tape (Figure 4). 

Figure 4 

m) Deburr the four holes drilled in the frequency adapter (1). 

n) Deburr the four holes drilled in the bush (4). 

o) Remove any chips and clean the bush and the frequency adapter (1). 

p) Protect the inner surface of the holes in the frequency adapter (1) and in the bush (4) with ALODINE 

1200, as per MTC Work Card 20.04.04.403. 

q) Protect the inner surface of the holes in the frequency adapter (1) and in the bush (4) with primer P05 

as per MTC Work Card 20.04.05.402. 

r) Remove the adhesive tape from the frequency adapter (1). 

s) Remove any chips from the frequency adapter (1) and from the bearing. 

t) Install the bush (4), the washers (3) and the screws (2), as per MET Work Card 62.20.00.402 or 

65.14.402. 

u) Prevent the bush (4) from turning by locking it with lockwire (5). Feed the lockwire through the two 

holes in the frequency adapter (1) and the bush (4) on the trailing edge of the frequency adapter 

(Figure 5). 

 

Figure 5 

5 4 
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v) Identify the part number of the frequency adapter post MOD 0762C39, in accordance with the table 

below and vibro-etch this part number below the existing part number in AREA Z, (size of the letters: 

2.5 to 4 mm) (Figure 6). After marking, cross out the previous part number in such a way that it is still 

legible. 

Figure 6 

Manufacturer Part 

Number 

EUROCOPTER Part 

Number 

pre MOD 0762C39 

EUROCOPTER Part 

Number 

post MOD 0762C39 

E1T 22305-01 704A33 640 016 365A31.1019.20 

E1T 2549-01 704A33 640 029 365A31.1019.21 

E1T2624-01A 704A33 640 031 365A31.1019.22 

E1T 3023-01 704A33 640 046 365A31.1019.23 

J 16130 10 704A33 640 087 365A31.1019.24 

E 4165 F01 704A33 640 088 365A31.1019.25 

J 16130 15 704A33 640 089 365A31.1019.26 

x) Install the frequency adapter on the attach beams of the same sleeve as identified previously, as per 

MET Work Card 62.20.00.402 or 65.14.402. 

2.B.3. Final steps 

- Install the main rotor blades as per MET Work Card 62.10.00.401 or 65.11.401. 

- Install the MGB cowlings as per MET Work Card 53.50.00.401 or 53.50.401. 

- If necessary, carry out dynamic balancing of the main rotor head, as per MET Work Card 62.20.00.603 

or 65.14.604. 
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2.B.4. On non-installed equipment, embodiment of MOD 0762C39 on the frequency adapters

a) On the frequency adapter (1), mark out the position of the four 8 mm diameter holes (two holes on the 

leading edge side and two holes on the trailing edge side, as shown on Figure 1). 

ON CERTAIN FREQUENCY ADAPTERS, WHEN 

DRILLING THE HOLES, THE “UP” MARKING OR THE 

SERIAL NUMBER AND THE DATE OF 

MANUFACTURE MAY BE DEFACED. 

IN THIS CASE, YOU MUST VIBRO-ETCH 

- THE "UP” MARKING IN AREA X (FIGURE 1), 

- THE SERIAL NUMBER AND THE DATE OF 

MANUFACTURE IN AREA Y (FIGURE 6). 

 (SIZE OF THE LETTERS: 2.5 TO 4 MM) 

b) Spot-drill the position of the four holes on the frequency adapter (1) as shown on Figure 1. 

NOTE 2

Adjust the drilling depth of the drill bit to avoid damaging 

the adapter. 

Use drill bits compatible with “aluminum” or “steel”. Do 

not lubricate. 

c) Drill four 4 mm diameter pilot holes in the frequency adapter (1). 

d) Drill out the four 4 mm diameter pilot holes using an 8 mm drill bit (Figure 3). 

e) Deburr the four holes drilled in the frequency adapter (1). 

f) Protect the inner surface of the holes in the frequency adapter (1) with ALODINE 1200 as per MTC 

Work Card 20.04.04.403. 

g) Protect the inner surface of the holes in the frequency adapter (1) with primer P05 as per MTC Work 

Card 20.04.05.402. 

h) Remove any chips from the frequency adapter (1). 

i) Identify the part number of the frequency adapter post MOD 0762C39, in accordance with paragraph 

2.B.2.v. 

CAUTION 
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2.B.5. On non-installed equipment, embodiment of MOD 0762C39 on frequency adapter bushes 

a) Use a frequency adapter post MOD 0762C39, as a tool. 

b) Fit the washers (3) and the screws (2) to hold the bush (4) in place during drilling (Figure 2). 

NOTE 3

Adjust the drilling depth of the drill bit to avoid damaging 

the bearing with the protruding tip of the drill bit. 

Use drill bits compatible with “aluminum” or “steel”. Do 

not lubricate. 

c) Drill the four holes using an 8 mm drill bit (Figure 3). 

d) Remove the screws (2), the washers (3) and the bush (4) from the frequency adapter (1) (Figure 2). 

e) Deburr the four holes drilled in the bush (4) 

f) Protect the inner surface of the holes in the bush (4) with ALODINE 1200 as per MTC Work Card 

20.04.04.403. 

g) Protect the inner surface of the holes in the bush (4) with primer P05 as per MTC Work Card 

20.04.05.402. 

NOTE 4

- After rework of the bushes 350A31 1885.21, their part 

number becomes 365A31 10 18 21. 

- After rework of the bushes 350A31 1885.22, their part 

number becomes 365A31 10 18 22. 

- The part number of the new bush definitions is 

365A31 1018 22
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2.B.6. Checking that the lockwire is in place and that the holes are not blocked 

As shown on Figure 5: 

- Check that the lockwire (5) is in place on the trailing edge side of the frequency adapter and that the 

four holes are not blocked. 

. If the lockwire (5) is in place on the trailing edge side of the frequency adapter and if the four holes are 

not blocked: 

- Leave as is and resume flights. 

. If the lockwire (5) is not in place on the trailing edge side of the frequency adapter: 

- Re-position the bush (4) if it has turned, and fit the lockwire (5) before resuming flights. 

- Inform the EUROCOPTER Technical Support Department by: 

. Tel: +33 (0)4.42.85.99.67 

. Fax: +33 (0)4.42.85.99.66. 

. If one or more holes or more is/are blocked, unblock the hole(s) before resuming flights. 

NOTE 5

Frequency adapters post MOD 0762C39 are subject to 

the same scheduled checks (Maintenance Program 

(PRE)) and the same removal criteria as frequency 

adapters pre MOD 0762C39. 

2.C. IDENTIFICATION 

Record embodiment of MOD 0762C39 and compliance with this ALERT SERVICE BULLETIN on the log 

card (FM) of the main rotor head. 

2.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

Not applicable. 
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3. MATERIAL INFORMATION 

3.A. MATERIAL: COST - AVAILABILITY 

Not applicable. 

3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT 

Not applicable. 

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

3.C.1. Kit(s) or component(s) to be ordered for one helicopter or one assembly 

Not applicable. 

3.C.2. Items to be ordered separately 

 Product 

Part Number 

Qty Item Key Word 

 

* MIL-DTL-81706 A/R ALODINE 1200 

* DHS186-111-20 A/R Primer paint P05 

* EN3628-0,8 A/R 5 Lock wire, 0.8 mm dia. 

 

The products 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

Telephone: +49.41.91.809.300 

AOG: +49.41.91.809.444 
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3.D. PROCUREMENT CONDITIONS 

Order the required quantity (unless otherwise specified) 

from 

EUROCOPTER 

Etablissement de Marignane 

Sales and Customer Relations Directorate 

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. 

4. APPENDIX 

Not applicable.