BOLLETTINO TECNICO N° 139-404 

The technical content of this document is approved 

under the authority of DOA nr. EASA.21J.005 DATE December 22, 2014

REV. /

Compliance with

this bulletin is: 

Page 1 of 14

SUBJECT 

FULL ICE PROTECTION SYSTEM (FIPS) TAIL ROTOR (TR) SLIP RING 

REASON 

To inspect and replace TR slip ring screws and to confirm the correct lockwiring. 

HELICOPTERS AFFECTED 

All the TR slip ring P/N 4G6420V00151, P/N 4G6420V00152 and P/N 4G6420V00153

both installed on AW139 helicopters and kept in stock.

NOTE 

Helicopters installing one of the Kits Partial Removal 

Arrangement (P/N from 4G3000F00311 to 

4G3000F00319) are also affected by this Bollettino 

Tecnico. 

NOTE 

TR slip rings having letter “T” marked after the S/N or 

“MOD 1” marked in the MFG plate are already 

compliant with this Bollettino Tecnico and do not 

need to be inspected. Refer to figure 1 for possible 

markings location. 

AgustaWestland S.p.A

Via Giovanni Agusta, 520

21017 Cascina Costa di Samarate (VA) Italy

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

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.
B.T. 139-404

Page 2 of 14

COMPLIANCE

Within thirty (30) flight hours or one (1) month from receipt of this Bollettino Tecnico, 

whichever comes first.

DESCRIPTION

An in service occurrence leading a separation between the slip ring body and the 

supporting ring have been forced to be due to a non conformity of the mounting screws 

installation.

The intent of this Bollettino Tecnico is to confirm absence of additional non conformities 

on parts already delivered.

Follow on actions may be expected at the conclusion of the investigation.

REQUIRED MANPOWER

It is estimated that in order to accomplish this Bollettino Tecnico three (3) maintenance 

man-hours (MMH) are necessary.

Man-hours are based on hands-on time and may vary with personnel and facilities 

available.

WARRANTY

 Owners/Operators who comply with the instructions of this Bollettino Tecnico no later 

than the applicable date in the “Compliance section” will be eligible to receive 

necessary parts on a free of charge basis, with the exception of Special Tools.

NOTE: Customers who fail to comply with the instructions in this Bollettino Tecnico

before the compliance date are not eligible for the aforementioned special policy.

 Please Issue relevant M.M.I.R. form ( Maintenance Malfunction Information Report ) 

to your Warranty Administration Dpt.; in case TAIL ROTOR SLIP RING HAS TO BE 

REPLACED AND RETURNED, PLEASE PROCEED WITH ITS SHIPMENT WITHIN 7 

DAYS FROM THE RECEIPT OF RELEVANT Return Material Authorization (RMA).
B.T. 139-404

Page 3 of 14

REQUIRED MATERIALS

Refer to Moog Service Bulletin SB 14-02 in annex A for the materials required to comply 

with this Bollettino Tecnico:

NOTE

A Tail Rotor Slip Ring P/N 4G6420V0153 can be 

ordered to AgustaWestland in case the part affected 

by this Bollettino Tecnico failed the check.

Applicability Note

 For three digit S/N xxx()() (i.e. 051()()), items listed in SB 14-02 table 

2 (this materials could be included in the kit P/N JJ6828KIT1).

 For four digit S/N yyyy()() (i.e.1001()()), items listed in SB 14-02 

table 3 (this materials could be included in the kit P/N JJ6828KIT2).

(1) (5)

(2) (5)

Moreover, the following consumable materials, or equivalent, are necessary to 

accomplish this Bollettino Tecnico:

SPEC./AW Code Number DESCRIPTION Q.TY NOTE

ASTM Specification D5363-03 Two part thread locking epoxy,

Armstrong C7/W or equivalent

AR Local supply

(3)

MIL-L-19537C Acrylic Lacquer (C081) AR Local supply

SPECIAL TOOLS

The following special tools, or equivalent, are required for compliance with this Bollettino 

Tecnico:

SPEC./AW Code Number DESCRIPTION Q.TY NOTE

RMGE-DS-06-2010-RH

or approved alternative

Platform, right (GG-02-00) AR (4)

Commercial Permanent black ink felt pen AR Local supply
B.T. 139-404

Page 4 of 14

SPEC./AW Code Number DESCRIPTION Q.TY NOTE

/ Mirror AR Local supply

/ Hand torch AR Local supply

/ Torque wrench AR Local supply

Notes

(1) Screw P/N NAS1352N06H12 may be used as an alternative to P/N NAS1352N06-

12.

(2) Screw P/N NAS1352N06H14 may be used as an alternative to P/N NAS1352N06-

14.

(3) Loctite 242/MS (blue), Loctite 243 (blue) and Loctite 270 (green) may be used as an 

alternative.

(4) Refer to Illustrated Tools and Equipment Publication (ITEP). See DM n° 39-A-GG02-00-00A-066A-A.

(5) Item 3 is local supply also.

WEIGHT AND BALANCE CHANGES

N.A.

REFERENCES

 AW139 Aircraft Material Data Information (AMDI)

 AW139 Aircraft Maintenance Publication (AMP)

 AW139 Illustrated Tools and Equipment Publication (ITEP)

PUBLICATIONS AFFECTED

N.A.
B.T. 139-404

Page 5 of 14

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 AMP, see 

DM n° 39-A-00-20-00-00A-120A-A.

2. Put the platform (GG-02-00), or an approved alternative, adjacent to the right side of 

the fuselage.

3. Remove the access panels 360AT and 360CT. Refer to AMP, see DM n° 39-A-06-

41-00-00A-010A-A.

NOTE

Inspection described in Moog Service Bulletin SB 14-

02 can be performed on wing. If necessary, use 

mirror and torch to inspect holes as requested in step 

6 of Moog Service Bulletin SB 14-02 compliance 

instructions.

4. Perform the inspection and replacement of the mounting screws and re-install the 

lockwire according to Moog Service Bulletin SB 14-02 in annex A. If the test fails,

return the slip ring to AgustaWestland and replace it with a new one, according to 

AMP DM n° 39-B-64-21-05-00A-520A-A and DM n° 39-B-64-21-05-00A-720A-A.

5. Mark on the identification plate the letter “T” after the serial number of the unit by 

means of permanent black ink felt pen and apply acrylic lacquer (C081).

6. Install the access panels 360AT and 360CT removed at step 3.

7. Remove the platform (GG-02-00) from the right side of the fuselage.

8. Return the helicopter to flight configuration and record for compliance with this 

Bollettino Tecnico on the helicopter logbook.

9. Record for compliance with this Bollettino Tecnico and update the slip ring S/N on 

the component logcard.
B.T. 139-404

Page 6 of 14

Figure 1
B.T. 139-404

Page 7 of 14

Annex A

MOOG

Service Bulletin SB 14-02 Rev. D







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: 

AGUSTAWESTLAND S.p.A. 

CUSTOMER SUPPORT & SERVICES - ITALY

PRODUCT SUPPORT ENGINEERING DPT.

Via del Gregge, 100

21015 Lonate Pozzolo (VA) - ITALY 

Tel.: +39 0331 664905

Fax: +39 0331 664684

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.