XX

TRANSLATION OF

 

BOLLETTINO TECNICO

N° 109S-35

The technical content of this document is approved 

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

DATE December 11, 2009

REV. xxxxxxx 

Compliance with 

this bollettino is: 

 XX Page 1 of 8

SUBJECT: MODIFICATION OF THE “BATT BUS” CIRCUIT BREAKER 

INSTALLATION. 

REASON: Modify the fuselage electrical installation P/N 109-0742-52 and the 

overhead panel electrical installation P/N 109-0742-55, by means of the 

“BATT BUS” circuit breaker modification kit P/N 109-0824-73-107. 

HELICOPTERS AFFECTED:

All Agusta A109S helicopters up to S/N 22151 included. 

COMPLIANCE:

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

Bollettino and, however, not later than June 30, 2010. 

DESCRIPTION:

During investigations conducted by Agusta on the electrical power 

generation system of the A109 series 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 

109-0824-73-107, for the replacement of the 35 Amps circuit breaker with a 

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

ones. 

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
B.T.109S-35

Page 2 of 8

REQUIRED MANPOWER:

An estimated of 8 (eight) 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 

109-0824-73-107 “BATT BUS” circuit breaker 1

modification kit

consisting of:

A583A2610W Stowage cap .4

CCH-36-101-0075 Conductive tape .1 roll

MS25244-50

or

30-072-1 50A circuit breaker .1

or

700-001-50

109-0824-73-111 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:

Accomplishment of this Bollettino has the following effect on weight and 

balance:

WEIGHT

(kg)

STA

(mm)

MOMENT

(kgmm)

0.605 3688 2231.2

REFERENCES:

0B-A-AMP-00-X Maintenance Publication.

PUBLICATIONS AFFECTED:

0B-A-AWDP-00-X Wiring Data Publication.

0B-A-IPD-00-X Illustrated Parts Data Publication.
B.T.109S-35

Page 3 of 8

COMPLIANCE INSTRUCTIONS:

(See figures 1÷3)

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

any power supply.

2. In accordance with instructions given in the 0B-A-AMP-00-X 

Maintenance Publication, gain access to the baggage compartment, 

open the panel assy D19 and remove the panels P66 and P67.

3. With reference to figure 2 view C-C, on STA 4910.0 bulkhead,

identify the 35 Amps “BATT BUS” circuit breaker.

4. Electrically disconnect and remove from the bulkhead the 35 Amps 

“BATT BUS” circuit breaker.

5. With reference to figure 3 detail D and figure 1 wiring diagram,

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

K7201 battery relay located in the baggage compartment.

NOTE

As an alternative, it is possible to stow the 

wire provided the installation of two stowage 

caps P/N A583A2610W.

6. With reference to figure 3 detail D and figure 1 wiring diagram, 

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

relay.

7. With reference to figure 2 view C-C and figure 1 wiring diagram, to 

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 temporary 

install it on STA 4910.0 bulkhead.

8. In accordance with instructions given in the 0B-A-AMP-00-X 

Maintenance Publication, remove the transmission forward fairing 

P15, the engine air intake D28 and the panel P46B.

9. In accordance with instructions given in the 0B-A-AMP-00-X 

Maintenance Publication, open the overhead panel and with 

reference to figure 3 detail E, identify the bus-bar of the “DAU CH-A” 

and “EDU 1” circuit breakers.

10. With reference to figure 3 detail E and figure 1 wiring diagram, from 

the bus-bar disconnect the wire marked P140B10.

11. With reference to figure 1, remove the wire marked P140B10.
B.T.109S-35

Page 4 of 8

NOTE

As an alternative it is possible to stow the wire 

provided the installation of two stowage caps 

P/N A583A2610W.

12. With reference to figure 1 cable routing and relevant wiring diagram, 

route the wire marked P140B8 from the circuit breaker P/N 

MS25244-50 located on STA 4910.0 bulkhead up to the “DAU CH-A” 

and “EDU 1” circuit breakers bus-bar into the overhead panel, 

following the existing harness routing, through the electronic 

compartment, the RH upper beam, and the overhead panel.

13. Connect the part covered with the copper braid (between the RH

upper beam outlet and the overhead panel inlet) of the cable assy 

P/N 109-0824-73-111, to the others braids installed on the 

helicopters using conductive tape P/N CCH-36-101-0075.

NOTE

If installed remove and then restore the PVC 

cover.

14. With reference to figure 3 detail E and figure 1 wiring diagram, 

connect the wire marked P140B8 to the “DAU CH-A” and “EDU 1” 

circuit breakers bus-bar using the existing fixing hardware.

15. With reference to figure 2 view C-C, from STA 4910.0 bulkhead 

remove the circuit breaker P/N MS25244-50 and in accordance with 

figure 1 wiring diagram connect the wire marked P140B8.

16. Definitively install the circuit breaker P/N MS25244-50 on STA 

4910.0 bulkhead.

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

harness using MIL-T-43435 lacing cord.

18. In accordance with instructions given in the 0B-A-AMP-00-X 

Maintenance Publication, close the overhead panel, the panel assy

D19, reinstall the panels P66 and P67, the engine air intake D28 and 

the panel P46B (restoring the seal).

19. Perform the following checks:

19.1 Connect a suitable external electrical power source in accordance 

with instructions given in the 0B-A-AMP-00-X Maintenance 

Publication.

19.2 Ensure that the GEN BUS 1 and the GEN BUS 2 switches are OFF.

19.3 Position the INV 1 switch ON.
B.T.109S-35

Page 5 of 8

19.4 Check that the Radio Master switch, on the miscellaneous panel, is 

ON.

19.5 Verify that the following systems are operative:

LANDING LIGHT

EHSI & EADI PLT

EDU 1 & EDU 2

INVERTER 1

LANDING GEAR INDICATOR

FUEL PUMP 1 & 2

GPS/NAV1

19.6 Disconnect the external electrical power supply in accordance with 

instructions given in the 0B-A-AMP-00-X Maintenance Publication.

19.7 Restore the initial conditions.

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

21. Record the accomplishment of this Bollettino in the helicopter log 

book.
B.T.109S-35

Page 6 of 8

FIGURE 1
B.T.109S-35

Page 7 of 8

FIGURE 2
B.T.109S-35

Page 8 of 8

FIGURE 3
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 del Gregge, 100

21015 Lonate Pozzolo (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.