ALERTX

TRANSLATION OF 

BOLLETTINO TECNICO

N° 109-132

The technical content of this document is approved 

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

DATE October 22, 2010

REV. xxxxxxx 

Compliance with 

this bollettino is: 

 ALERT Page 1 of 7

SUBJECT: TAIL ROTOR HUB AND BLADES INSTALLATION SPECIAL HUB PLUG 

P/N 109-0133-18-103, INSPECTION OF.

REASON: Perform a one-time inspection of the subject special hub plug to verify 

the application of the right tightening torque value and provide the 

instructions to restore the correct installation.

HELICOPTERS AFFECTED:

All the Agusta A109A and A109AII helicopters that have performed the 

special hub plug P/N 109-0133-18-103 tightening in accordance with the 

instructions given in the A109A/AII Maintenance Manual, revision 9 dated 

June 15, 2009 or subsequent revisions, except the Temporary Revision 

n°65-4 dated September 28, 2010.

COMPLIANCE:

Within the next 5 flight hours after the receipt of this Bollettino and 

however within and not later than November 30, 2010.

DESCRIPTION:

During the installation of the tail rotor hub on an A109A series helicopter, 

in the publication A109A/AII Maintenance Manual has been reported an 

inaccuracy in the tightening torque to apply at the special hub plug 

P/N 109-0133-18-103.

The publication A109A/AII Maintenance Manual, Chapter 65-20-00, point 

F, step e., for the tightening of the special hub plug P/N 109-0133-18-103 

indicates for a torque of 57 to 67 kgcm (51 to 60 in.lb). Actually the

drawing of the tail rotor installation requests for the hub plug a tightening

torque of 600 to 700 kgcm.

The investigations revealed that the mistake has been inserted in the 

maintenance manual with the revision 9 dated June 15, 2009. The 

ALERT

ALERT

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. 109-132

Page 2 of 7

publication A109A/AII Maintenance Manual has been revised with the

Temporary Revision n°65-4 dated September 28, 2010 to introduce the 

right tightening torque value.

This Bollettino is issued in order to provide the necessary instructions to 

perform a one-time inspection to verify the correct tightening torque 

application to the special hub plug P/N 109-0133-18-103 and, if 

necessary, to restore the design conditions and the inspection of the tail 

rotor hub and blade assy P/N 109-0131-02 (all dashes) trunnion 

broaching and the tail rotor gearbox assy P/N 109-0440-01 output drive 

shaft broaching. 

REQUIRED MANPOWER:

For compliance with this Bollettino an estimated 2 (two) manpower hours 

are required in case the tightening torque value is correct. In case the

value is not correct 7 (seven) manpower hours are required.

WARRANTY:

Within the calendar terms mentioned at point “Compliance”, the parts 

required to apply the present Bollettino shall be supplied on a free of 

charge basis by Agusta upon Customer’s request.

Upon application of this Bollettino, Customers are requested to submit to 

Agusta Warranty Administration the Technical Bulletin Compliance form 

attached to this Bulletin duly completed in all its parts, and the relevant 

M.M.I.R. (Maintenance Malfunction Information Report).

REQUIRED MATERIALS:

The following materials are required for compliance with this Bollettino:

P/N DENOMINATION Q.TY 

109-0133-17-103 Lock washer 1

MS29561-119 O-ring 1

SPECIAL TOOLS:

Refer to the A109A/AII Maintenance Manual.

WEIGHT AND BALANCE CHANGES:

N.A.

REFERENCES:

A109A/AII Maintenance Manual.

PUBLICATIONS AFFECTED:

N.A. 

COMPLIANCE INSTRUCTIONS:

(See figures 1÷3)

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

disconnect any power supply.
B.T. 109-132

Page 3 of 7

2. Gain access to the special hub plug P/N 109-0133-18-103 in 

accordance with the procedures given in the A109A/AII 

Maintenance Manual.

3. Verify the tightening torque of the special hub plug 

P/N 109-0133-18-103 as follows:

 

3.1 With reference to figure 1, from the special hub plug 

P/N 109-0133-18-103 raise the winglets of the lock washer 

P/N 109-0133-17-103.

3.2 Using a torque wrench verify that the tightening torque value of 

the special hub plug P/N 109-0133-18-103 is at least 600 kgcm.

3.3 If the tightening torque value is correct, replace the lock washer

P/N 109-0133-17-103 and the MS29561-119 o-ring with new 

parts with the same P/N and complete the installation of the tail 

rotor system parts in accordance with the procedures given in the 

A109A/AII Maintenance Manual. No corrective action is required, 

proceed as described in steps 11 and 12.

CAUTION

The special hub plug P/N 109-0133-18-103 

must be torque up to 600 to 700 kgcm.

3.4 If the tightening torque value is lower than the required, proceed 

as described in steps 4 and subsequent.

4. Remove the tail rotor hub and blades assy P/N 109-0131-02 (all 

dashes) in accordance with the procedures given in the 

A109A/AII Maintenance Manual.

5. With reference to figure 2, inspect the broaching (F) and the 

bearing faces (D) of trunnion P/N 109-0131-05 or 

P/N 109-8131-33 of the tail rotor hub and blades assy 

P/N 109-0131-02, for spalling, fretting, wear and/or other 

damages.

5.1 Medium-heavy spalling on bearing faces (D) out of the limits 

shown in figure 2 involves the trunnion replacement with a new 

part with the same P/N.

5.2 Slight spalling on bearing faces (D) within the limits shown in 

figure 2 is acceptable and does not require rework.

5.3 Wear spalling on the broaching (F) involves the trunnion 

replacement with a new part with the same P/N.
B.T. 109-132

Page 4 of 7

5.4 Perform the dimensional check of the broaching (F), dimensions 

exciding the limits shown in figure 2 involves the trunnion 

replacement with a new part with the same P/N.

5.5 With reference to figure 1, inspect the special hub plug 

P/N 109-0133-18-103, the spacer P/N 109-0133-16-103, the 

spacer P/N 109-0130-89-1 and the static stop

P/N 109-0130-27-5 for damages and/or corrosion. Presence of 

damages and/or corrosion involves the relevant part replacement 

with a new part with the same P/N.

6. With reference to figure 3, inspect the broaching (H) of the output 

drive shaft P/N 109-0445-08-3/-7 of the tail rotor gearbox assy 

P/N 109-0440-01 for fretting, wear and/or other damages.

6.1 Fretting presence could not be acceptable. Contact Agusta.

6.2 Other damages presence is not acceptable. Contact Agusta.

6.3 Damages of 0.07 mm or more in depth between loaded and not 

loaded areas are not acceptable. Contact Agusta.

6.4 Inspect the output drive shaft P/N 109-0445-08-3/-7 of the tail 

rotor gearbox assy P/N 109-0440-01 in accordance with the 

procedures given in the A109A/AII Maintenance Manual.

7. Reinstall the tail rotor hub and blades assy P/N 109-0131-02 in 

accordance with the procedures given in the A109A/AII 

Maintenance Manual.

CAUTION

The special hub plug P/N 109-0133-18-103 

must be torque up to 600 to 700 kgcm.

8. Perform the flap axis play check in accordance with the 

procedures given in the A109A/AII Maintenance Manual.

9. Perform the flap hinge friction check in accordance with the 

procedures given in the A109A/AII Maintenance Manual.

10. Perform the tail rotor dynamic balance in accordance with the 

procedures given in the A109A/AII Maintenance Manual.

11. Return the helicopter in ready to flight condition.

12. Record compliance of this Bollettino in the helicopter log book.
B.T. 109-132

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FIGURE 1
B.T. 109-132

Page 6 of 7

FIGURE 2
B.T. 109-132

Page 7 of 7

109-0445-08-3/-7 T/R GEARBOX OUTPUT DEIVE SHAFT

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 664600

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.