BOLLETTINO TECNICO N° 109-147

The technical content of this document is approved 

under the authority of DOA nr EASA.21J.005. DATE March 25th, 2015

REV. April 07, 2011 

Compliance with 

this bulletin is: 

Page 1 of 4

SUBJECT: TAIL ROTOR DRIVE SHAFT P/N 109-8412-02-1 and -3. 

REASON: Provide the necessary instructions to inspect the tail rotor drive shaft 

assy P/N 109-8412-02-1 and -3 for cracks. 

HELICOPTERS AFFECTED: 

 All the AgustaWestland A109 A helicopters that install the retrofit kit

109-0820-27-101 by application of BT 109-045.

 All the AgustaWestland A109 AII / C helicopters.

COMPLIANCE: 

Within and not later than 50 flight hours or 3 months after the date of

issuance of this Bollettino Tecnico. 

DESCRIPTION:

During a scheduled servicing on an A109S three cracks have been found 

on the tail rotor drive shaft assy P/N 109-8412-02-1.

Cracks are not related to fatigue failure of the shaft subject to the design 

loads. 

As a precautionary measure AgustaWestland has issued this Bollettino 

Tecnico to prescribe a “one time” tail rotor drive shaft inspection for 

cracks within the time allowed in the “COMPLIANCE” paragraph.

REQUIRED MANPOWER: 

An estimated 9 manpower hours are required for compliance with this 

Bollettino. 

WARRANTY:

Owners/Operators who comply with the instructions of this Bulletin, no 

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

to receive REQUIRED MATERIALS on free of charge basis. 

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. 109-147

Page 2 of 4

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

before the compliance date are not eligible for the aforementioned 

special policy.

Please Issue relevant M.M.I.R. form ( (M)aintenance (M)alfunction 

(I)nformation (R)eport ) to your Warranty Administration Dpt.

REQUIRED MATERIALS:

The following materials may be required to apply this Bollettino if the 

prescribed inspection gives negative results:

P/N DENOMINATION Q.TY

109-8412-02-1 TR drive shaft assy A.R.

109-8412-02-3 TR drive shaft assy A.R.

The following consumable material is required to apply this Bollettino:

SPECIFICATION DENOMINATION Q.TY

TT-N-95 Aliphatic Naphtha A.R.

Ty 2 (Code 531055030)

MIL-C-16173D Corrosion inhibitor A.R.

Grade 2 CL 2 (Code 999999999000000194)

SPECIAL TOOLS:

Magnifying glass 5X 

WEIGHT AND BALANCE CHANGES:

N.A.

REFERENCES:

Pertinent Maintenance Manual.

PUBLICATIONS AFFECTED:

N.A.

COMPLIANCE INSTRUCTIONS:

1. Prepare the helicopter on ground for a safe maintenance and

disconnect any power supply, in accordance with the instructions 

given in the Pertinent Maintenance Manual.

2. Gain access to the tail rotor drive shaft opening all the necessary 

doors and panels in accordance with the instructions given in the 

Pertinent Maintenance Manual.

3. Remove both tail rotor drive shaft assemblies P/N 109-8412-02-1

and -3 in accordance with the instructions given in the Pertinent 

Maintenance Manual.

4. Perform the inspection of the tail rotor drive shafts for cracks as 

follows:
B.T. 109-147

Page 3 of 4

4.1. Clean the components of the tail rotor drive shaft installation with 

the clean Cloth and the Aliphatic naphtha.

4.2. Dry with filtered compressed air.

CAUTION

Apply the Corrosion inhibitor to the tail 

rotor drive shaft components if you do not 

do the inspection immediately after their 

removal and cleaning.

4.3. Examine the external surface of the Tail rotor shaft P/N 109-8412-

02-1 and -3 for cracks with the help of the Magnifying glass 5X and 

a source of light.

5. If no cracks are found reinstall the TR drive shaft in accordance with 

the instructions given in the Pertinent Maintenance Manual and go 

to step 7.

6. If cracks are found replace the TR drive shaft assy P/N 109-8412-

02-1 and/or -3 (depending of inspection results) with a new one in 

accordance with the instructions given in the Pertinent Maintenance 

Manual.

7. Reinstall all the panels and close all the doors removed or opened

in the step 2.

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

9. Send the attached compliance form to the following email box:

Aw109.mbx@agustawestland.com.

As an alternative, gain access to My Communications section on 

Leonardo Web Portal on AW website and compile the “Technical 

Bulletin Application Communication.
B.T. 109-147

Page 4 of 4

FIGURE 1

(Crack Example)
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.