T.F.S. No. 00000577 

Approved under EASA DOA No. 21J.056. Page 1/11 

2010.04.22

EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE CEDEX FRANCE

EMERGENCY

ALERT SERVICE BULLETIN 

COLIBRI Number VERSIONS 

Civil: B EC120 24A012 

SUBJECT: ELECTRICAL POWER

 EMERgency SWitch (EMER SW) wiring

REVISION No. DATE OF APPROVAL DATE OF ISSUE

 

Revision 0 On: April 22, 2010 2010.04.22 

 

This document is available on the internet: www.eurocopter.com/techpub
T.F.S. No. 00000577 

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2010.04.22

THE INFORMATION AND INSTRUCTIONS 

CONTAINED IN THIS ALERT SERVICE BULLETIN 

ARE INTENDED FOR MAINTENANCE PERSONNEL 

AND FLIGHT CREWS. 

1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/installed equipment 

Helicopters equipped with "EMER SW" switch with a Serial Number (S/N) listed below: 

- S/N 1500, 

- S/N between 1511 and 1630 (terminals included), 

- S/N 1632, 1634 and 1636. 

1.A.2. On non-installed equipment 

Not applicable. 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

Modification of the "EMER SW" switch wiring. 

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

1.D. DESCRIPTION 

As part of a test conducted at EUROCOPTER, the "smoke in the cockpit" procedure was applied. It 

was found that setting the "EMER SW" switch to "CUT-OFF" (low position) and the "GENE" 

pushbutton to "OFF" at the same time, caused the aircraft starter-generator to cut-in again. 

The technical investigations conducted revealed that cross-wiring at the "EMER SW" switch caused 

the malfunction. In this configuration, the "smoke in the cockpit/cargo" procedure described in the flight 

manual does not isolate the equipment electrical power supply. 

Consequently, EUROCOPTER renders the embodiment of the modification described in this ALERT 

SERVICE BULLETIN, mandatory. 

CAUTION 
T.F.S. No. 00000577 

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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 

Not applicable. 

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

Not applicable.

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

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

- Comply with paragraph 2.B of this ALERT SERVICE BULLETIN within 15 flight hours, without 

exceeding 1 month, following receipt of this ALERT SERVICE BULLETIN, issued on the date 

indicated at the foot of the page. 

- Before the next flight following receipt of this ALERT SERVICE BULLETIN, inform the flight 

crews of the content of this ALERT SERVICE BULLETIN and draw their attention to the 

instruction below: 

Pending compliance with paragraph 2.B., in case of smoke in the cockpit with a source not 

identified, the flight crew must follow the appended procedure. 

1.E.2.b. Non-installed equipment 

Not applicable. 

1.F. APPROVAL 

1.F.1. Approval of modifications 

The information or instructions related to FAM No. RFA 08090 approved on April 9, 2010 by EASA for 

civil version helicopters subject to an Airworthiness Certificate. 

1.F.2. Approval of the Service Bulletin 

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

on April 22, 2010 under the authority of EASA Design Organisation Approval No. 21J.056 for civil 

version helicopters subject to an Airworthiness Certificate. 
T.F.S. No. 00000577 

Approved under EASA DOA No. 21J.056. Page 4/11 

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1.G. MANPOWER 

1.G.1. Qualification 

- 1 electrical engineering technician (Modification to the wiring as per § 2.B.2.). 

- 1 pilot or 1 approved technician entitled to perform run-up.(Tests as per § 2.B.4.). 

1.G.2. Time for the operations 

- Approximately 30 minutes (Modification to the wiring as per § 2.B.2.). 

- Approximately 30 minutes (Tests as per § 2.B.4.). 

1.H. WEIGHT AND BALANCE 

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS 

Does not affect the helicopter electrical power breakdown. 

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD 

Not applicable. 

1.K. REFERENCES 

- Aircraft Maintenance Manual (AMM): 

AMM: Task 24-00-00,3-1. 

1.L. OTHER DOCUMENTS AFFECTED 

The following documents will be issued subsequently: 

- Wiring Diagrams Manual (WDM). 

1.M. TOOLING AFFECTED 

Not applicable. 

1.N. INTERCHANGEABILITY OR MIXABILITY OF PARTS 

Not applicable. 
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2. ACCOMPLISHMENT INSTRUCTIONS 

2.A. GENERAL 

- Read and comply with the general instructions concerning the electrical power supply as per AMM 

Task 24-00-00,3-1. 

2.B. OPERATIONAL PROCEDURE 

2.B.1. Preliminary steps 

- Remove the instrument panel vizor (a). 

2.B.2. Wiring modification (Figures 1 and 2) 

- Using tool (zz), reconnect "EMER SW" (3PA) switch wires in compliance with Figure 2: 

. Wire marked "2431-0016" to terminal "3PA-1A". 

. Wire marked "2431-0003" to terminal "3PA-2A". 

2.B.3. Final steps 

- Install the instrument panel vizor (a). 

2.B.4. Tests 

To validate correct operation of the "EMER SW" switch, the following tests must be performed: 

- Set the helicopter into the following configuration: 

. [AVIONIC] (if installed) ON 

. [BAT/EPU] ON 

. [EMER SW] ON 

. Start-up the helicopter 

. [GENE] ON 

- Perform the following tests: 

. [EMER SW]: OFF 

Check that the equipment items are no longer energized, except: the engine, NR / NTL 

instrument and emergency lights (utility lights). 

. [BAT/EPU]: OFF 

Check that the equipment items are no longer energized, except: the engine, NR / NTL 

instrument and emergency lights (utility lights). 

. [GENE]: OFF 

Check that the equipment items are no longer energized, except: the engine, NR / NTL 

instrument and emergency lights (utility lights). 

. [EMER SW]: ON 

Check that the equipment items are no longer energized, except: the engine, NR / NTL 

instrument and emergency lights (utility lights). 
T.F.S. No. 00000577 

Approved under EASA DOA No. 21J.056. Page 6/11 

2010.04.22

. [BAT/EPU]: ON 

Check that all equipment items are energized. 

. [BAT/EPU]: OFF 

. [GENE]: ON 

Check that all equipment items are energized. 

- Stop the engine and rotors. 

- Replace snapwire (b) (Figure 1) with snapwire (1). 

2.C. IDENTIFICATION 

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

2.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

2.D.1. Operating instructions 

Not applicable. 

2.D.2. Scheduled maintenance instructions 

Not applicable. 

2.D.3. Unscheduled maintenance instructions

Pending update of WDM 24-30-01-002, refer to the wiring diagram of Figure 2, when performing a 

maintenance operation on the "EMER SW" switch. 

The wiring modification will be incorporated in WDM 24-30-01-002 as part of a future revision. 
T.F.S. No. 00000577 

Approved under EASA DOA No. 21J.056. Page 7/11 

2010.04.22

Figure 1 - "EMER SW" Switch 
T.F.S. No. 00000577 

Approved under EASA DOA No. 21J.056. Page 8/11 

2010.04.22

Figure 2 - "EMER SW" Switch Wiring 

POST EASB 24A012

PRE EASB 24A012
T.F.S. No. 00000577 

Approved under EASA DOA No. 21J.056. Page 9/11 

2010.04.22

3. MATERIAL INFORMATION 

3.A. MATERIAL: PRICE AND AVAILABILITY 

3.A.1. Cost 

Not applicable. 

3.A.2. 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 

Not applicable. 

3.C.2. Products to be ordered separately 

 Material P/N Qty Item Key Word

 

* 23321 A/R 1 Snapwire

 

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: 

INTERTURBINE, 

Website: http://www.itlogistics.de

Phone: +49.41.91.809.300 

AOG: +49.41.91.809.444 

3.C.3. Tools

Material P/N Qty Item Key Word

 

M81969-14-11 1 zz Extraction tool 

 
T.F.S. No. 00000577 

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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 

The "Smoke in the cockpit/cargo - Source not identified" procedure is appended. 
T.F.S. No. 00000577 

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

2010.04.22

Appendix