MANDATORY

An appropriate entry should be made in the aircraft log book upon accomplishment.

If ownership of aircraft has changed, please, forward to new owner.

An Company

Via GiovanniAgusta, 520

21017 Cascina Costa di Samarate (VA) Italy

Tel.: +39 0331-229111 - Fax: +39 0331-229605/222595

XX 

TRANSLATION OF

BOLLETTINO TECNICO N° 109EP-98

The technical content of this document is approved 

under the authority of DOA nr EASA.21J.005. 

DATE June 22, 2009

REV. xxxxxxx 

Compliance with 

this bollettino is: 

 XX Page 1 of 7

SUBJECT: MODIFICATION OF THE “BATT BUS” CIRCUIT BREAKER 

INSTALLATION. 

REASON: Modify the fuselage electrical installation P/N 109-0741-49 and the 

overhead panel electrical installation P/N 109-0741-55, by means of the 

“BATT BUS” circuit breaker modification kit P/N 109-0824-73-101. 

HELICOPTERS AFFECTED:

All Agusta A109E helicopters as given below: 

• up to S/N 11077 included, that install kit P/N 109-0812-04-101 or -103, 

or -107, or -109; 

• from S/N 11078 to S/N 11758 included, except the S/N 11741, 11754 

and 11757. 

COMPLIANCE:

Within and not later than 50 (fifty) flight hours after the receipt of this 

Bollettino and however within and not later than December 31, 2009. 

DESCRIPTION:

During investigations conducted by Agusta on the electrical power 

generation system of the A109E helicopter, it has been discovered that the 

35 Amps “BATT BUS” Circuit Breaker characteristics resulted not within 

design requirements. In the event of a double electrical failure involving, at 

least, one of the generators, “BATT BUS” Circuit Breaker with degraded 

characteristic may result marginal in case of improper use of both landing 

and search lights. 

This Bollettino has been issued with the purpose to provide the necessary 

instructions to apply the “BATT BUS” circuit breaker modification kit P/N 

109-0824-73-101, for the replacement of the 35 Amps circuit breaker with a 

50 Amps circuit breaker and the replacement of the wires with oversized 

ones. 
B.T.109EP-98 

Page 2 of 7 

REQUIRED MANPOWER:

An estimated 5 (five) manpower hours are required for compliance with this 

Bollettino. 

WARRANTY:

The parts required to apply the present Bollettino shall be supplied on a free 

of charge basis by Agusta upon request, except the consumable materials. 

Upon application of this Bollettino, Customers are requested to submit to

Agusta Warranty Administration the Technical Bulletin Compliance form 

attached to this Bollettino duly completed in all its parts. 

REQUIRED MATERIALS:

The following materials are required for compliance with this Bollettino: 

P/N DENOMINATION Q.TY 

109-0824-73-101 “BATT BUS” circuit breaker 1 

 modification kit 

consisting of: 

A583A2610W Stowage cap .4 

MS21042-L4 Nut .1 

MS25244-50 

or 

30-072-1 50A circuit breaker .1 

or 

700-001-50 

AN4-3A Bolt .1 

MS51957-26 Screw .2 

MS51957-27 Screw .2 

MS51957-28 Screw .2 

MS51957-29 Screw .2 

MS51957-30 Screw .2 

NAS1149D0416H Washer .2 

999-8001-74-211 Busbar .1 

109-0824-73-105 Cable assy .1 

In addition the following consumable material is necessary: 

SPECIFICATION DENOMINATION Q.TY 

MIL-T-43435 Lacing cord A.R. 

 (code 900004953) 

SPECIAL TOOLS:

N. A. 

WEIGHT AND BALANCE CHANGES: 

Negligible.

REFERENCES:

A109E Maintenance Manual. 
B.T.109EP-98 

Page 3 of 7 

PUBLICATIONS AFFECTED:

A109E Maintenance Manual; 

A109E Illustrated Parts Catalog up to S/N 11600; 

A109E Illustrated Parts Catalog S/N 11601 and subs. 

COMPLIANCE INSTRUCTIONS:

(See figures 1÷2) 

1. Prepare the helicopter on ground for a safe maintenance, disconnect 

any power supply. 

2. Acting on the relevant fixing hardware remove the glareshield, the 

instruments panel central fairing, the right side door P/N 109-0312-95 

and, if installed, the instruments panel lower covers, located behind 

the pilot pedals. 

3. With reference to figure 1 detail A, behind the pilot pedals identify the 

35 Amps “BATT BUS” circuit breaker. 

4. Acting on the relevant fixing hardware remove the circuit breaker 

support. 

5. Electrically disconnect and remove from the support the 35 Amps 

“BATT BUS” circuit breaker. 

6. With reference to figure 1 detail A and figure 2 wiring, diagram 

disconnect and remove the wire marked P140A10 from pin A1 of the 

K7201 battery relay. 

NOTE

As an alternative it is possible to stow the wire 

after the installation of two stowage caps P/N 

A583A2610W. 

7. With reference to figure 1 detail A and figure 2 wiring diagram, 

connect the wire marked P140A8 to pin A1 of the K7201 battery 

relay. 

8. With reference to figure 1 detail A and figure 2 wiring diagram, on the 

wire marked P140A8 connect the circuit breaker P/N MS25244-50 or 

P/N 30-072-1 or P/N 700-001-50 (50 Amps) and install it on the 

support. 

9. Open the overhead panel and with reference to figure 2 detail B, 

identify the busbar P/N 109-0745-03-137 (or 999-8001-74-211 if 

already installed) of the “DAU CH-A” and “EDU 1” circuit breakers. 
B.T.109EP-98 

Page 4 of 7 

10. With reference to figure 2 detail B and figure 2 wiring diagram, from 

the busbar P/N 109-0745-03-137 (or 999-8001-74-211 if already 

installed) disconnect the wire marked P140B10. 

11. From the overhead panel, if the busbar P/N 999-8001-74-211 is not 

already installed, acting on the relevant fixing hardware remove the 

busbar P/N 109-0745-03-137. 

12. With reference to figures 1 and 2, remove the wire marked P140B10. 

NOTE

As an alternative it is possible to stow the wire 

after the installation of two stowage caps P/N 

A583A2610W. 

13. With reference to figure 2 detail B and figure 2 wiring diagram, in the 

overhead panel (if no already installed) install the busbar P/N 999-

8001-74-211 using the previously removed fixing hardware. 

NOTE

If necessary, replace the “DAU CH-A” and 

“EDU 1” circuit breaker screws, with screws 

selected from P/N MS51957-26 to P/N 

MS51957-30 of adequate length. 

14. With reference to figures 1 and 2, route the wire marked P140B8 

from the busbar P/N 999-8001-74-211, located inside the overhead 

panel, to the circuit breaker P/N MS25244-50, behind the pilot 

pedals, following the existing harness routing. 

NOTE

To facilitate the operation from the instruments 

panel remove the instruments and/or the 

panels involved in the wire route. 

15. With reference to figure 2 detail B and figure 2 wiring diagram, 

connect the wire marked P140B8 to the busbar P/N 999-8001-74-

211 using a bolt P/N AN4-3A, two washers P/N NAS1149D0416J 

and a nut P/N MS21042-L4. 

16. With reference to figure 1 detail A and figure 2 wiring diagram, 

connect the wire marked P140B8 to the circuit breaker P/N 

MS25244-50 or P/N 30-072-1 or P/N 700-001-50 (50 Amps). 

17. Reinstall the circuit breaker support using the previously removed 

fixing hardware. 
B.T.109EP-98 

Page 5 of 7 

18. Secure the wires marked P140A8 and P140B8 to the existing 

harness using MIL-T-43435 lacing cord. 

19. Close the overhead panel and reinstall the glareshield, the 

instruments panel central fairing, the right side door P/N 109-0312-95 

and, if installed, the instruments panel lower covers, located behind 

the pilot pedals using the previously removed fixing hardware. 

20. Perform the following checks: 

NOTE

During execution of the following checks, each 

time the MASTER CAUTION and/or MASTER 

WARNING lights illuminate, reset them by 

pressing relative pushbutton. 

20.1 Ensure that all circuit breakers of overhead panel are open and all 

switches are set to “OFF” or “NORMAL”. 

20.2 Ensure that the circuit breakers “BATT RELAY” and “BATT BUS” are 

closed. 

20.3 Connect a suitable external electrical power source in accordance 

with instructions given in the A109E Maintenance Manual. 

20.4 Close the circuit breaker “EDU 1” and check that the EDU 1 is 

powered. 

20.5 Close the circuit breaker “DAU CH A” and check that on the EDU 1 

the parameters are in COMPOSITE mode. 

20.6 Close the circuit breaker “INTERCOM PLT” and check operation of 

the ICS 1. 

20.7 Disconnect the external electrical power supply in accordance with 

instructions given in the A109E Maintenance Manual. 

20.8 Restore the initial conditions. 

21. Return the helicopter to a ready to flight condition. 

22. Record compliance with this Bollettino in the helicopter log book. 
B.T.109EP-98 

Page 6 of 7 

FIGURE 1
B.T.109EP-98 

Page 7 of 7 

FIGURE 2

Note: 

Remarks:

Informazioni: 

Information:

Al fine di gestire le varianti alla configurazione base, in relazione all’emissione del Bollettino Tecnico, preghiamo di voler compilare il presente modulo in tutte le sue parti e spedirlo all’indirizzo sopra indicato. Si ringrazia per la gentile collaborazione data. 

We request your cooperation in filling this form, in order to keep out statistical data relevant to aircraft configuration up-to-date. The form should be filled in all 

its parts and sent to the above address. We thank you beforehand for the information given.

MODULO APPLICAZIONE BOLLETTINO TECNICO

TECHNICAL BULLETIN COMPLIANCE FORM

Data: 

Date:

Numero: 

Number:

Revisione: 

Revision:

Prego spedire a questo indirizzo: 

Please send to the following address: 

AGUSTA S.p.A. 

CUSTOMER SUPPORT & SERVICES - ITALY

PRODUCT SUPPORT ENGINEERING DPT.

Via per Tornavento, 15 

21019 Somma Lombardo (VA) - ITALY 

Tel.: +39 0331 711100 

Fax: +39 0331 711180

Telefono: 

Telephone:

Fax:

Data Applicazione B.T.: 

B.T. Compliance Date:

Denominazione Cliente ed Indirizzo: 

Customer Name and Address:

Modello Elicottero 

Helicopter Model S/N Matricola Tail Number

Ore Totali 

Total Hours

Ore D.U.R. 

T.S.O.