Page 1 of 7

BOLLETTINO TECNICO

The technical content of this document is approved

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

N° 412-134

DATE July 15, 2013 

REV.

Compliance with

this bulletin is:

SUBJECT: SWASHPLATE OUTER RING ASSEMBLY P/N 412-010-407-105, 

REMOVAL FROM SERVICE.

REASON: Remove from service the subject swashplate outer ring assembly.

HELICOPTERS AFFECTED:

COMPLIANCE:

Within the next 5 flight hours after the issue of this Bollettino and subsequently every 25 

flight hours until removal from service, which as to be done within 300 flight hours after the 

issue of this Bollettino or not later than April 15, 2014 whichever comes first.

The swashplate outer rings assembly P/N 412-010-407-105 must not be used after April 15, 

2014; the swashplate outer ring assembly P/N 412-010-407-117 must to be installed in lieu of 

swashplate outer ring assembly P/N 412-010-407-105.

DESCRIPTION:

AgustaWestland has received two reports of cracking in the swashplate outer ring assemblies 

P/N 412-010-407-105. The investigations have identified in both case a fatigue failure, 

therefore this Bollettino mandates the removal from service of all swashplate outer ring 

assembly P/N 412-010-407-105.

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.

ALERT

ALERT
B.T. 412-134

Page 2 of 7 

MANPOWER REQUIRED: 

Approximately 26 man-hours are required to complete this Bollettino. 

WARRANTY:

Owners / Operators of AgustaWestland AB412 who comply with the instructions of this 

Bollettino will be eligible to receive a pro-rated credit for the replacement swashplate outer 

ring assembly P/N 412-010-407-117, and cap P/N 540-011-434-111 outlined under the 

requirement material section of this Bollettino, together with the labor cost to cover the 

replacement on bench and on the aircraft. 

To receive this credit:

Purchase the required 412-010-407-117 outer ring assembly and cap 540-011-434-111 

from a AgustaWestland supply source. 

Comply with the instructions contained in this Bollettino no later than the applicable hours 

in the “compliance section” of this Bollettino, or before April 15, 2014. 

Labor cost provided for a replacement an on bench assembly will be $400.00 USD and 

$800.00 USD for an on aircraft assembly. 

Submit an WMM to the AgustaWestland Warranty Department for the replacement parts 

and the appropriate labor cost. 

MATERIAL REQUIRED: 

The following material is required for the accomplishment of this Bollettino.

P/N DENOMINATION Q.TY

412-010-407-117 Outer ring assembly 1

412-010-404-101 Shim 1

204-011-429-1 Seal 2

540-011-434-111 Cap assembly 1

140-007-21S18C6 Washer 14

MS21042L5 Nut 16
B.T. 412-134

Page 3 of 7

MS21250-05022

or

NAS625-22

Bolt 14

AN960-516

or

NAS1149F0563P

Washer 16

SPECIAL TOOLS: N.A.

WEIGHT AND BALANCE CHANGE: N.A.

REFERENCES:

AB412-IPC Illustrated Parts Catalogue

BHT-412-CR&O Component Repair and Overhaul Manual

AB412-MM Maintenance Manual

PUBBLICATIONS AFFECTED:

AB412-MPM Maintenance Planning Manual Chapter 4

AB412-IPC Illustrated Parts Catalogue

ACCOMPLISHMENT INSTRUCTIONS:

1. Prepare helicopter for safe ground maintenance. Disconnect battery and all the electric power 

source and/or the external power supply.

2. Remove forward pylon fairing assembly in accordance with AB412-MM, and clean 

swashplate outer ring with clean cloth damp in denatured alcohol or equivalent.

3. Using a 5X magnifying glass and a bright light visually inspect the swashplate outer ring P/N 

412-010-407-105 for cracks (Refer to Figure 1 and Figure 2 for typical crack found during 

inspection).

4. If the inspection does not reveal cracks, re-install forward pylon firing assembly previously 

removed and return the helicopter to flight configuration. Make an entry in helicopter 

applicable documentations indicating compliance of the inspection with this Bollettino. 

5. If the inspection reveal cracks, remove and replace the swashplate outer ring assembly P/N 

412-010-407-105 with P/N 412-010-407-117 in accordance with the following instructions:

5.1. Remove swashplate and support assembly in accordance with AB412-MM Chapter 62- 31-
B.T. 412-134

Page 4 of 7 

02 step 2. 

5.2 Disassembly swashplate and support assy for enter to outer ring in accordance with BHT412-CR&O Chapter 62-00-00 paragraph 62-30. Scrap outer ring P/N 412-010-407-105, 

shim P/N 540-011-436-3, seals P/N 204-011-429-1 and cap assy P/N 540-011-434-1. 

5.3 Install seals P/N 204-011-429-1 in new outer ring P/N 412-010-407-117 and cap P/N 540-

011-434-111 (lip pointing downward) in accordance with BHT-412-CR&O paragraph 62-

36 step 2. 

5.4 Reassemble swashplate and support assy in accordance with BHT-412-CR&O Chapter 62-

00-00 paragraph 62-36 using new shim P/N 412-010-404-101 an hardware listed in Figure 

3. Remark with P/N 412-010-402-111 the swashplate and support assy. 

5.5 Re-install the swashplate and support assembly in accordance with AB412-MM Chapter 62-

31-02 step 3. 

6. After re-assembly and installation of all components, the main rotor assembly shall be 

tracked and balanced in accordance with AB412-MM Maintenance Manual. 

7. Upon completion, make an entry in helicopter applicable documentations indicating 

compliance with this Bollettino. 
B.T. 412-134

Page 5 of 7

Figure 1

Swashplate outer ring,

area to be inspected all around
B.T. 412-134

Page 6 of 7 

Figure 2

Crack on swashplate outer 

ring P/N 412-010-407-105 
B.T. 412-134

Page 7 of 7

Figure 3

DENOMINATION PRE B.T. POST B.T. 

Ref. P/N Ref. P/N

Outer Ring Assy 1 412-010-407-105 1A 412-010-407-117

Shim 2 540-011-436-3 2A 412-010-404-101

Seal 3 204-011-429-1 3 204-011-429-1

Cap Assy 4 540-011-434-1 4A 540-011-434-111

Washer 5 140-007-21S18C6 5A 140-007-21S18C6

Nut 6 MS21042L5 6A MS21042L5

Bolt 7

MS21250-05022

or

NAS625-22

7A

MS21250-05022

or

NAS625-22

Washer 8

AN960-516

or

NAS1149F0563P

8A

AN960-516

or

NAS1149F0563P

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.