## BOLLETTINO TECNICO N° 

# 139-166

The technical content of this document is approved under the authority of DOA nr. EASA.21J.005 DATE April 6, 2009

REV

. /

Compliance with this bulletin is:

page 1 of 26 SUBJECT: MODULAR AVIONIC UNITS

REASON : inspect MAU#1 and MAU#2. Improve MAU#2 installation for corrosion prevention.

HELICOPTERS AFFECTED: AB139/AW139 short nose confi guration helicopters: from S/N 31005 to S/N 31157 (except S/N 3100 7, S/N 31094 and S/N 31149) and from
S/N 41001 to S/N 41023.

COMPLIANCE: within 300 flight hours or six (6) months from rece ipt of this Bollettino,
whichever comes first.

DESCRIPTION: corrosion of MAU#2 cards due to salt water and external moisture has
been identified as a contributor y factor in some in-flight emergency occurrences. In particular Custom I/O #2 cards have been verified to be susceptible to this type of corrosive agents. This Bollettino provides the necessary instructions to inspect the MAU#2 cards in order to ensure that they are corrosi on free. Moreover an improvement of the
MAU#2 ventilation duct installation is im plemented in order to move the MAU#2 cards away from the direct flow of ai r coming from the vent ilation duct outlet.

## B.T. 139-166

page 2 of 26 Even though no event of corrosion has been verified on MAU#1 cards, as a precautionary measure, also the MAU#1 cards are inspected.

REQUIRED MANPOWER: it is estimated that in order to accomplish this Bollettino eight (8) man-hours (MMH) are necessary. Man-hours are based on hands-on time and may vary with personnel and facilities
available.

WARRANTY:

• Upon request, the parts required to apply this Bollettino shall be supplied on a free of charge basis by Agusta, exc ept for the consumable materials.

• Upon application of this Bo llettino Tecnico, Customers are requested to submit to Agusta Warranty Administration a Ma intenance Malfunction Information report duly completed in all its parts.

REQUIRED MATERIALS: the following materials are necessary to accomplish this bollettino and can be required to AgustaWestland:

P/N DESCRIPTION Q.TY
3P5340A40251 (1) Connector 1
3G5306P25451 Plate 1

CONSUMABLE MATERIALS: moreover the following consumable materials are necessary to comply with this bollettino:

SPEC./AW Code Number DESCRIPTION Q.TY NOTE 199-05-002, Type I, Class 2 – Code no. 900000581 Adhesive AR local supply 199-05-002, Type II, Class 2 – Code no. 900004603 Adhesive, EA 934NA AR local supply AMS-C-9084 Ty. VIIIB Cl. 1 Code no. 900005846 Glass Fiber AR local supply

## B.T. 139-166

page 3 of 26 SPEC./AW Code Number DESCRIPTION Q.TY NOTE 199-50-002, Type I – Code no. 900001557 Resin AR local supply 199-50-002, Type II – Code no. 900001558 Hardener AR local supply / Sticker 6 local supply

Notes (1) alternative P/N 3A534 0A40251 might be supplied.

SPECIAL TOOLS: the following special tools are necessary to accomplish this
bollettino: P/N DESCRIPTION Q.TY Local supply Light source 1

WEIGHT AND BALANCE CHANGES: N.A.

REFERENCES:
9 AW139 Aircraft Maintenance Publication (AMP)

PUBLICATIONS AFFECTED: N.A.

COMPLIANCE INSTRUCTIONS:
1. Prepare the helicopter for a safe ground maintenance. Disconnect the battery and all the electrical power sources and/or the external power supply. Refer to Aircraft Maintenance Public ation (AMP), see DM n° 39-A-00-20-00-
00A-120A-A.

2. Remove the Number 2 modul ar avionics unit (MAU2) cabinet. Refer to AMP, see DM
n° 39-A-31-42-01-00A-720A-A.

## B.T. 139-166

page 4 of 26 NOTE To perform MAU2 removal at step 2 it is necessary to remove (among the others) from the MAU2 cabinet the following MAU modules to be inspected at step 3:

- Number 2 power supply (PS2) module,

- Number 2 custom input/output (CSIO2) module,

- Number 2 control input/output (CIO2) module.

CAUTION Only personnel trained by AgustaWestland or Honeywell is permitted to do the inspection described at following step 3.
3. Do a general visual inspection of the MAU modules and related connectors according to the following instructions:
NOTE Modules to be inspect ed are the following:

- Power Supply (PS) module P/N 7024440-1901,

- Custom I/O (CSIO) module P/N 7025410-1901,

- Control I/O (CIO) module P/N 7026534-1902.
3.1 Visually examine the connectors of the MAU modules for signs of corrosion (refer to attachment 1 of this Bo llettino for detailed instructions).
3.2 If you find any sign of corrosion, clean the connector before further installation (refer to attachment 1 of this Bo llettino for detailed instructions).
3.3 Visually examine the MA U modules for structural in tegrity and for evidence of corrosion (refer to attachment 1 of this Bolletti no for detailed instructions).
3.4 If you find sign of corrosion, get a new module for installation at step 12 (MAU2) or step 13 (MAU1). Contact AW to coordinate the shipment of the removed module for reconditioning
3.5 If you don’t find any sign of corrosion continue the inspection on all the modules
listed in NOTE.

## B.T. 139-166

page 5 of 26 3.6 Apply a sticker on every inspected module and mark “BT 139-166 applied”.

4 Remove from Number 1 modular avioni cs unit (MAU1) cabinet the modules listed beyond. Refer to AMP, see DM listed in the following table:
39-A-31-41-02-00A-520A-A Nu mber 1 power supply (PS1) module – Remove procedures 39-A-31-41-03-00A-520A-A Nu mber 1 custom input/output (CSIO1) module – Remove procedures 39-A-31-41-04-00A-520A-A Nu mber 1 control input/output (CIO1) module – Remove procedures
5 Repeat the inspection descri bed at step 3 for MAU#1 modules removed at step 4.
6 Disconnect the RH ventilation pipe as follows:
6.1 Remove the AFT right float assembly, if installed. Refer to AMP, see DM n° 39-
A-95-61-04-00A-520A-K.
6.2 If the AFT right float assembly is not installed, remo ve lower panel P/N 3P5340A01631 (184BR). Refer to figure 1 for panel position.
6.3 With reference to figure 2, get access to the air duct hose (2) and remove the clamp (1) that holds the hose on the connector (3).
6.4 Disconnect the hose (2) from the connector (3).

7 Remove the external skin P/N 3P5340A38651 (180ER) as follows:
7.1 With reference to figures 1 and 4, remove access panel 182AR (6).
7.2 With reference to figure 4, remove the screws (13) and t he washers (14) that hold the support (12) on the floor. Retain the hardware for re-use.
7.3 Remove the support (12).
7.4 Remove the screws (17) and the washer s (18) that hold the AFT RH vertical angle assy (19) on the angl e assy (20). Retain the hardware for re-use.
7.5 With reference to figure 3, remove t he screws (2) and the was hers (3) that hold the AFT RH vertical angle assy (4) on t he joint assy (5). Retain the hardware
for re-use.
7.6 Remove the AFT RH vertical angle assy (4).

## B.T. 139-166

page 6 of 26 7.7 With reference to figure 4, remove the screws (16) and th e washers (15) that hold the angle assy (20) on the floor . Retain the hardware for re-use.
7.8 Remove the angle assy (20).

7.9 Remove screws and washers that hold the FWD floor P/N 3P5340A03631 (panel 180ER) on the helicopter.

7.10 Remove the FWD floor P/N 3P5340A 03631 (180ER) from the helicopter.
8 With reference to figures 5 thru 8, rework FWD floor P/N 3P5340A03631 as follows:

8.1 Trim connector P/N 3P5340A40251 from FWD fl oor P/N 3P5340A03631 as shown in figure 8 section B-B. Make sure to avoid damage to the panel.
8.2 Close the existing hole using plate P/N 3G5306P25 451 as shown in figure 6 view A. Install the plate on the upper side of the panel using adhesive 199-05- 002 Type I Class 2.

8.3 Perform a 69 mm φ hole on the FWD floor P/ N 3P5340A03631 in the new position as shown in figure 6 view A.

8.4 Install connector P/ N 3P5340A40251 in the hole us ing adhesive 199-05-002 Type I Class 2 as shown in figure 6 section C-C.

8.5 Rename FWD floor with P/N 3G5306P25411.

9 Install FWD floor P/N 3G5306P25411 on the he licopter using hardware removed at step 7.10.
10 With reference to figure 2, connect the ai r duct hose (2) to the connector (3) installed at step 6.3 using the clamp (1). Refer to figure 7 for the new air duct hose positioning.
11 With reference to figures 3 and 4, inst all support, angles and panels removed at step 7, using previously retained hardware.

12 Install the MAU2 cabinet. Refer to AM P, see DM n° 39-A-31-42-01-00A-720A-A.
NOTE Instructions to install MAU2 modules and to perform the related operational ch ecks are provided in AMP

## B.T. 139-166

page 7 of 26 Data Modules referenced in DM n° 39-A-31-42-01- 00A-720A-A referred to in step 10.
13 Install in the MAU1 cabinet the modules listed beyond. Refer to AMP, see DM listed in the following table:
39-A-31-41-02-00A-720A-A Nu mber 1 power supply (PS1) module – Install procedures 39-A-31-41-03-00A-720A-A Nu mber 1 custom input/output (CSIO1) module – Install procedures 39-A-31-41-04-00A-720A-A Nu mber 1 control input/output (CIO1) module – Install procedures

NOTE Instructions to perform t he related operational checks are provided in AMP Data Modules referenced in DM referred to in step 13. 14 Install the AFT right float assembly (re fer to AMP, see DM n° 39-A-95-61-04-00A520A-K) or the lower panel P/N 3P5340A01631 (184BR) , whichever has been removed at step 6.
15 Report the results of the inspection per formed at steps 3 and 5 to AW139 Product Support Engineering ( aw139.mbx@agustawestland.com ).
16 Return the helicopter to flight confi guration and record for compliance of this
bollettino.

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page 8 of 26 Figure 1

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page 9 of 26 Figure 2

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page 10 of 26 Figure 3 STRUCTURE AND SYSTEMS ARE PARTIALLY OMITTED FOR CLARITY PURPOSES

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page 11 of 26 Figure 4 STRUCTURE AND SYSTEMS ARE PARTIALLY OMITTED FOR CLARITY PURPOSES

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page 12 of 26 Figure 5

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page 13 of 26 Figure 6

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page 14 of 26 Figure 7

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page 15 of 26 Figure 8

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page 26 of 26Note: Remarks:

Informazioni: Information: Al fine di gestire le varianti alla configur azione base, in relazione all’emissione de l Bollettino Tecnico, preghiamo di voler compilare il presente modulo in tutte le sue parti e sped irlo all’indirizzo sopra indicato. Si ring razia 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.**
PRODUCT SUPPORT ITALY Via per Torna v en t o, 15 21019 Som m a Lombardo (VA) - I T ALY T el

. : +39 0331 711100 Fa x : +39 0331 711 180

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.