### T.F.S. No. 00000579

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

2010.04.23 EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE C EDEX F RANCE



# EMERGENCY 

# ALERT SERVICE BULLETIN

ECUREUIL NUMBER VERSIONS



# AS350 05.00.62 Civil: Military: B-BA-BB-B1-B2-D

L1


# AS355 05.00.57 Civil: E-F-F1-F2-N



# AS550 05.00.38 Military: A2-C2-U2



# AS555 05.00.35 Military: AF-AN-SN-UF-UN



### SUBJECT: TIME LIMITS / MAINTENANCE CHECKS

Periodic inspection of the Tail Gear Box (TGB) control lever

ATA : 65



### REVISION No. DATE OF APPROVAL DATE OF ISSUE

Revision 0 On: March 30, 2010 2010.03.31 Revision 1 On: April 22, 2010 2010.04.23

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

### T.F.S. No. 00000579

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

2010.04.23 CAUTION

THE INFORMATION AND THE INSTRUCTIONS

CONTAINED IN THIS ALERT SERVICE BULLETIN

ARE INTENDED FOR MAINTENANCE PERSONNEL

AND FOR FLIGHT CREWS.



### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

Helicopters equipped with a Tail Gear Box (TGB) fitted with a control lever P/N:
- 350A33-1058-00,
- 350A33-1058-01,
- 350A33-1058-02,
- 350A33-1058-03,

and not marked with an "X" in the area shown in Figure 7.

NOTE 1

The following are not concerned by the instructions given

in this ALERT SERVICE BULLETIN: 1) Control levers P/N:
- 350A33-1524 all dash numbers,

- 350A33-1526 all dash numbers. 2) Control levers P/N: 350A33-1058-00/01/02/03 marked with an "X" in the area shown in Figure 7.

1.A.2. Non-installed equipment

- Tail Gear Boxes (TGBs) fitted with a cont rol lever P/N 350A33-1058- 00/01/02/03 and not marked

with an "X" in the area shown in Figure 7.

- Control levers P/N 350A33-1058-00/01/02/03 and not marked with an "X" in the area shown in Figure 7.



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.

### T.F.S. No. 00000579

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2010.04.23 

### 1.C. REASON

1) To monitor TGB control levers to make sure there are no cracks. 2) To prevent the risk of cracks occurring in TGB control levers.

Revision 0 of this ALERT SERVICE BULLETIN di d not form the subject of an EASA Airworthiness

Directive.

The purpose of Revision 1 of this ALERT SERVICE BULLETIN is to extend the deadline for application of the rework procedure described in paragraph 2.B.3. to 660 hours, without exceeding
June 30, 2011.

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

Directive.



### 1.D. DESCRIPTION

Revision 0 : An accident occurred involving an AS350 B2 helicopter; the cause of the accident was the failure of

control lever P/N 350A33-1058-03. Initial investigations on site showed that the area of failure of the control lever was similar to that in cases encountered previously where it was demon strated that the crack was due to non-compliant

installation. Therefore EUROCOPTER issued Safety Informati on Notice (SIN) No. 2106-S-65 on October 29, 2009, to remind operators of the installation proced ure and of the checking instructions which are applicable following installation of the control lever. Concerning the latest case, further investigations have not formally concluded non-compliant installation of the TGB control lever; only a few surface anomalies were revealed. In order to remove any surface anomalies which could lead to reduced strength, EUROCOPTER has defined mandatory local reworking of the area concerned. Pending this rework, a visual inspection of the area is required during the ALF check in order to detect any cracks. An analysis of this incident has determined that only the control levers with the part numbers specified in paragraph 1.A.1. are concerne d by the instructions given in this ALERT SERVICE BULLETIN.

Revision 1 : Following the issue of Revision 0, many operators preferred ordering new, reworked or reinforced levers, although there was no technical difficulty in carrying out the rework operation defined in paragraph 2.B.3. In view of this unexpected increase in the numbe r of orders, and considering that the ALF check guarantees the safety of the daily f lights, EUROCOPTER has extended t he time limit for retrofitting the fleet, in accordance with the instructions of paragraph 1.E.2.

### T.F.S. No. 00000579

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2010.04.23 

### 1.E. COMPLIANCE

EUROCOPTER renders compliance with th is ALERT SERVICE BULLETIN mandatory.

1.E.1. Compliance at the works

1.E.1.a. On helicopters:

Comply with paragraph 2.B.3. before delivery of helicopters.

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

Comply with paragraph 2.B.3. before delivery to customers.

1.E.2. Compliance in service

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

1) Comply with paragraph 2.B.1. during the next ch eck after the last fli ght of the day, without exceeding 10 flying hours, following receipt of this ALERT SERVICE BULLETIN issued on the date indicated at the foot of the page
Then, Comply with paragraph 2.B.1. during each chec k after the last flight of the day, without exceeding 10 flying hours, until compliance is ensured with paragraph 2.B.3. which describes the rework procedure necessary to raise complianc e with the instructions given in this ALERT

SERVICE BULLETIN.

2) Comply with paragraph 2.B.3. within 660 flyi ng hours following receipt of Revision 0 of this ALERT SERVICE BULLETIN, issued on March 31, 2010, and at the latest by June 30, 2011.

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

Comply with paragraph 2.B.3. before installation on a helicopter and at the latest before June 30,

2011.



### 1.F. APPROVAL

1.F.1. Approval of modifications

Not applicable.

1.F.2. Approval of the Service Bulletin

The technical information contained in this AL ERT SERVICE BULLETIN Révision 0 was approved on March 30, 2010 under the authority of EASA Design Organisation Approval No. 21J.056 for civil version helicopters subject to an Airworthiness Certificate.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 0 was approved on March 30, 2010 by the EUROCOPTER Airworthines s Department for military version helicopters.

### T.F.S. No. 00000579

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

2010.04.23 The technical information contained in this AL ERT SERVICE BULLETIN Revision 1 was approved on April 22, 2010 under the author ity of EASA Design Organisation A pproval No. 21 J.056 for civil version helicopters subject to an Airworthiness Certificate.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 1 was approved on April 22, 2010 by the EUROCOPTER Airworthine ss Department for military version helicopters.



### 1.G. MANPOWER

1.G.1. Qualification

1 Mechanical Engineering Technician,

Or 1 suitably trained pilot, qualified in accordance with the local regulation (only for the visual check specified in paragraph 2.B.1.).

1.G.2. Time for the operations

Approximately 5 minutes for the visual check. Approximately 3 hours to replace the control lever. Approximately 5 hours to locally rework the control le ver (including control lever removal / installation time).

1.G.3. Estimated helicopter grounding time

Less than 1 day.



### 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. 00000579

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

2010.04.23 

### 1.K. REFERENCES

Maintenance Manual (MET) Work Card:

- 65.20.00.401.

Standard Practices Manual (MTC) Work Cards:

- 20.02.05.404.

- 20.02.09.101.

- 20.02.09.601.

- 20.04.02.401.

- 20.04.04.401.

- 20.04.04.403.

- 20.04.05.402.

- 20.04.05.410.

- 20.08.05.103.



### 1.L. OTHER DOCUMENTS AFFECTED

Maintenance Program (PRE) section 05.98 or 05.99 will be modified in accordance with this ALERT

SERVICE BULLETIN.



### 1.M. TOOLING AFFECTED

Not applicable.



### 1.N. INTERCHANGEABILITY OR MIXABILITY OF PARTS

Not applicable.

### T.F.S. No. 00000579

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2010.04.23 

### 2. ACCOMPLISHMENT INSTRUCTIONS

2.A. GENERAL

NOTE 1

Eurocopter remains at your disposal for any additional information or support you may require in order to comply with the instructions giv en in this ALERT SERVICE
BULLETIN; contact the EUROCOPTER Customer Service Technical Support Department by: Tel.: +33 (0)4.42.85.99.67 Fax: +33 (0)4.42.85.99.66 Email: DynComp.Technical-Support@eurocopter.com



### 2.B. OPERATIONAL PROCEDURE

2.B.1. Procedure

2.B.1.a. Visual check of the control lever

Using a mirror , visually inspect control lever (a) in inspection area (A) shown in Figures 1 and 2,

and make sure that there are no cracks.

2.B.1.b. Interpretation of the results

1) If there are no cracks :

- Leave as is. - Resume flights.

2) If there is a crack :

- Contact the EUROCOPTER Customer Service Technical Support Department as per the

instructions in NOTE 1 in paragraph 2.A. - Replace affected control lever (a) with a new control lever (7) as per procedure 2.B.2. and

paragraph 3.C. - Resume flights.

### T.F.S. No. 00000579

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

2010.04.23 2.B.2. Removal / Installation of the control lever (Figure 3)

a) Removal of control lever (a)

- Open the TGB fairing, - Remove cotter pin (e) and remove nut (f), threaded pin (k) and washer (h), - Discard cotter pin (e), nut (f) and washer (h), - Remove cotter pin (g) and remove nut (j), screw (c) and washers (d), - Discard cotter pin (g), nut (j) and washers (d), - Remove expansible bolt (q) with spacer (p), cotter pin (n) and nut (m) as per MET Work Card

65.20.00.401.

CAUTION

WHEN YOU REMOVE THE EXPANSIBLE BOLT, YOU

MUST COMPLY WITH THE INSTRUCTIONS GIVEN ON

MET WORK CARD 65.20.00.401.

- Discard cotter pin (n) and nut (m). - Remove control lever (a).

b) Installation of control lever (7)

- Offer up control lever (7) on the TGB. - Install expansible bolt (q) with spacer (p), cotter pin (2) and nut (1) as per MET Work Card

65.20.00.401.

CAUTION

WHEN YOU INSTALL THE EXPANSIBLE BOLT, YOU

MUST COMPLY WITH THE INSTRUCTIONS GIVEN ON

MET WORK CARD 65.20.00.401.

- Install screw (c) and washers (6), then torque tighten nut (1) and safety with cotter pin (2). - Install threaded pin (k) and washer (3), then torque tighten nut (4) as per MTC Work Card

20.02.05.404 and safety with cotter pin (5). - Close the TGB fairing.

### T.F.S. No. 00000579

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2010.04.23 2.B.3. Rework procedure for area B of the control lever (Figures 4, 5 and 6)

NOTE 2

Only the rib shown in Figure 4 (Area B) is to be reworked.

- Remove the control lever as per paragraph 2.B.2.a.

For control levers which have logged flying hours :

- Before reworking area B of the control lever, ch eck that there are no cracks by performing a local

non-destructive inspection of the control leve r in inspection area A (See Figures 1 and 2): . Strip the inspection area of control lever (a) as per MTC Work Card 20.04.02.401. . Perform local non-destructive inspection of t he inspection area (for example, dye penetrant

inspection as per MTC Work Cards 20.02.09.101 and 20.02.09.601). - Interpret the results as per paragraph 2.B.3.a.

For control levers which have never been installed on a helicopter :

- Rework the control lever as per the proc edure described below in paragraph 2.B.3.b.

2.B.3.a. Interpretation of the results

1) If there are no cracks :

- Rework the control lever as per paragraph 2.B.3.b.

2) If there is a crack :

- Contact the EUROCOPTER Customer Service Technical Support Department as per the

instructions in NOTE 1 in paragraph 2.A. - Replace the control lever as per paragraph 2.B.2.b. and paragraph 3.C. - Resume flights.

2.B.3.b. Rework of the control lever

- Measure dimension "e" before starting the rework (Figure 4).

As per Figures 5 and 6 :

- Manually rework area B as per MTC Work Card 20.04.04.401.

. Sand area B progressively with P120-grit abras ive paper, then semi-finish the whole of the

reworked area with P400-grit abrasive paper, taking care to remove all surface scores and imperfections and while complying with the following conditions:

.. Remove a thickness of 0.3 to 0.4 mm. .. Comply with a minimum dimension "e" of 14 mm. .. There must be a minimum blending radius "R " of 3 mm between the rib and the base of the

yoke. Use a 6 mm or 7 mm-diameter drill shank wrapped in abrasive paper to produce the

radius.

### T.F.S. No. 00000579

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2010.04.23 .. Comply with dimension "C" of 2 mm maximum. .. Round off sharp edges on both sides of the reworked area. .. In the top part of the rework area, move up progressively in order to blend with the nonreworked part of the rib.

. Polish the whole of the reworked area in area B wi th Scotch Brite in order to obtain the highest

quality finish.

- Measure dimension "e" after rework.

. This dimension must be equal to dimension "e " measured before rework less 0.3 to 0.4 mm

without being less than 14 mm.

- Measure dimension "C" after rework.

. This dimension must not be greater than 2 mm.

- If dimension "e" or dimension "C" are out of tolerance:

. Contact the EUROCOPTER Customer Service Te chnical Support Department in accordance

with the procedures described in NOTE 1 of paragraph 2.A.

- If dimension "e" and dimension "C" are within the tolerances: - Protect area B with Alodine (8) as per MTC Work Card 20.04.04.403.

CAUTION

DO NOT PROTECT THE REWORKED AREA WITH

CHROME ANODIZING.

- Apply one coat of protective P05 primer pai nt (9) over area B as per MTC Work Card

20.04.05.402. - Apply a second coat of protective P05 primer paint (9) over area B as per MTC Work Card

20.04.05.402, allowing the drying time between the two coats. - Apply top coat paint (10) as per MTC Work Card 20.04.05.410. - Using indelible ink, mark an "X" on t he control lever as per paragraph 2.D.2. - Install the control lever as per paragraph 2.B.2.b. - Resume flights.



### 2.C. OPERATIONAL PROCEDURE ON NON-INSTALLED EQUIPMENT

Identical to paragraph 2.B.3.



### 2.D. IDENTIFICATION

2.D.1. Identification of modi fications in the documentation

a) Record first compliance with this ALERT SER VICE BULLETIN on the equipment log card (FM) of

the TGB.

b) Record compliance with paragraph 2.B.3. of this ALERT SERVICE BULLETIN on the equipment log card (FM) of the TGB.

### T.F.S. No. 00000579

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

2010.04.23 2.D.2. Identification of modifications on equipment

Mark an "X" on the control lever near to the control lever part number, as per MTC Work Card 20.08.05.103 and as per Figure 7:
. use indelible ink and, . apply VERNELEC 43022 protective varnish.



### 2.E. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable.

### T.F.S. No. 00000579

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

2010.04.23 Figure 1: Visual inspection of the control lever 

### a



# A

a 

# A A Ref.: TGB shaft

Ref.: Mirror

Ref.: TGB fairing

Ref.: Pitch-change unit Ref.: TGB casing yokes

### T.F.S. No. 00000579

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2010.04.23 Figure 2: Area of the control lever to be inspected 

# A

A

a



# A

### T.F.S. No. 00000579

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2010.04.23 Figure 3:

Removal / Installation of the control lever 

### a - 7

c d - 6 e - 5 f - 4 g - 2 h - 3 j - 1

m - 1

p q

n - 2 k

### T.F.S. No. 00000579

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2010.04.23 Figure 4: Reworking of the control lever 

# B

Dimension "e" 

# B

### T.F.S. No. 00000579

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2010.04.23 Figure 5: Reworking of the control lever 

### Before reworking

After reworking

Minimum radius = 3 mm

0.3 to 0.4 mm 2 mm maximum

14 mm minimum Round off sharp edges on

both sides of the reworked

area Move up progressively in order

to blend with the non-reworked
part of the rib

### T.F.S. No. 00000579

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2010.04.23 Figure 6: Reworking of the control lever Dimension « C » = 2 mm

### T.F.S. No. 00000579

Approved under EASA DOA No. 21J.056 Page 18/21

2010.04.23 Figure 7: Marking 

### Marking area

### T.F.S. No. 00000579

Approved under EASA DOA No. 21J.056 Page 19/21

2010.04.23 

### 3. MATERIAL INFORMATION

3.A. MATERIAL: PRICE AND AVAILABILITY

3.A.1. Cost

For all information concerning the price of kits and/ or components for the modifications, of tools or assistance, contact the Eurocopter Customer Service Sales Department or Network.

3.A.2. Availability

The kits or components or tools will be delivered on the customer's order.



### 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

MP/N SAP P/N

ASNA0044-080BCL 782658 2 1 Nut Replace 23310CA015020 740026 2 2 Cotter pin Replace 23111CA060 739933 1 3 Washer Replace ASNA0045-060BCL 1154014 1 4 Nut Replace 23310CA015015 740025 1 5 Cotter pin Replace 23112CA080 739946 2 6 Washer Replace

Control lever to be ordered separately

Material P/N Qty Item Key Word Instructions

MP/N SAP P/N

350A33-1058-03

Marked with an "X" on the

control lever Or 350A33105803 1 7 Control lever

350A33-1526-00 350A33152600 1 7 Reinforced

control lever

Or

350A33-1524-00 350A33152400 1 7 Reinforced

control lever

### T.F.S. No. 00000579

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2010.04.23 3.C.2. Material to be ordered separately

Material P/N Qty Item Key Word Instructions

MP/N SAP P/N

MIL-DTL-81706 AR 8 Alodine 1200 DHS186-111.20 86741 AR 9 P05 protection

DHS186-111.21 AR - Hardener

DHS186-111.22 AR - Thinner ECS2022.20-2640 AR 10 Top coat paint

NOTE 1

When ordering P05 primer paint (DHS186-111.20), please order hardener (DHS186-111.21) and thinner (DHS186-111.22).

The products necessary for comp liance with the Work Cards mentioned 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. Material to be modified at the Manufacturer's or to be returned

Not applicable.

3.C.4. Products to be ordered separately

Not applicable.

3.C.5. Tools

Not applicable.

3.C.6. Material supplied by the User

Not applicable.

### T.F.S. No. 00000579

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2010.04.23 

### 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 2

For ALERT SERVICE BULLETINS, order by:

Telex: HELICOP 410 969F Fax: +33 (0)4 42 85 99 96



### NOTE 3

On the purchase order, please specify the mode of transport, the destination and the serial numbers of the helicopters to be

modified.



### 3.E. MATERIAL TO BE RETURNED

Not applicable.



### 4. APPENDIX

Not applicable