TRANSLATION OF 

BOLLETTINO TECNICO N° 109K-53

The technical content of this document is approved 

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

 DATE December 18, 2009

 REV. , 

Compliance with 

this bulletin is: 

 Page 1 of 7 

SUBJECT: INSPECTION OF THE MAIN ROTOR SCISSOR FITTING ASSY 

P/N 109-0110-67 FIXING BOLTS P/N 109-0101-78-5. 

REASON: Perform a “one-time” inspection of the subject bolts to verify the presence 

of two washers under the head of each bolt and provide the instructions 

to restore the correct installation. 

HELICOPTERS AFFECTED:

All the main rotor hub assy P/N 109-0101-01 installed on the Agusta 

A109K2 helicopters or eventually in stock.

COMPLIANCE:

PART I^:

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

PART II^:

Within 25 flight hours after the compliance with PART I^ and however 

within and not later than April 30, 2010. 

DESCRIPTION:

A case of fracture of two of the three bolts P/N 109-0101-78-5 fixing the 

main rotor scissor fitting assy P/N 109-0110-67 has been reported in

flight on an A109K2 helicopter. 

The occurrence did not cause harm to the occupants nor damage to the 

helicopter. 

The investigations revealed that the malfunction was caused by incorrect 

information contained in the technical publications. 

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

perform a “one-time” inspection to verify the correct installation of the 

main rotor scissor fitting assy P/N 109-0110-67, that includes the 

installation of two washers under the head of each bolt 

P/N 109-0101-78-5 (PART I^) and, if necessary, to restore the design 

MANDATORY

An appropriate entry should be made in the aircraft log book upon accomplishment.

If owner ship of air c raft has changed, please, forward to new owner.

An Company

Via Giovanni Agusta, 520

21017 Cascina Costa di Samarate (VA) Italy

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

ALERT

ALERT
B.T. 109K-53

Page 2 of 7 

conditions by replacing the bolts P/N 109-0101-78-5 that were not 

installed following the correct sequence (PART II^). 

REQUIRED MANPOWER:

The following estimated manpower hours are required for compliance 

with this Bollettino: 

PART I^: Negligible; 

PART II^: 3 (three).

WARRANTY:

The parts required to apply the present Bollettino shall be supplied on a 

free of charge basis by Agusta upon request, except for consumable 

materials. 

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. 

REQUIRED MATERIALS:

PART I^:

N.A. 

PART II^:

The following materials are required for compliance with PART II^ of this 

Bollettino: 

P/N DENOMINATION Q.TY

109-0101-78-5 Bolt 3 

NAS1149C0463R Washer 3 

NAS1149C0432R Washer 3 

In addition the following consumable materials are necessary: 

SPECIFICATION DENOMINATION Q.TY

MS20995C32 Lockwire A.R. 

MIL-PRF-16173 Corrosion preventive compound A.R. 

GR 1 CL 2 (cod. 999999999000000191)

SPECIAL TOOLS:

N.A. 

WEIGHT AND BALANCE CHANGES: 

N.A. 

REFERENCES:

A109K2 Maintenance Manual. 

PUBLICATIONS AFFECTED:

 A109K2 Maintenance Manual; 

 A109K2 Overhaul Manual. 
B.T. 109K-53

Page 3 of 7

COMPLIANCE INSTRCTIONS:

PART I^:

(See figure 1)

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

disconnect any power supply.

2. With reference to figure 1, gain access to the main rotor hub and 

verify that under the head of the three fixing bolts 

P/N 109-0101-78-5 of the main rotor scissor fitting assy 

P/N 109-0110-67 two washers are installed.

 

2.1 If for each bolt two washers are installed, perform the step 3. and 

4.

NOTE

In this case the compliance with PART II^ of 

this Bollettino is not required.

2.2 Even if under the head of only one bolt a single washer is 

installed, perform the PART II^ within the compliance limits of this 

Bollettino. 

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

4. Record compliance with PART I^ of this Bollettino in the 

helicopter log book.

PART II^:

(See figures 1 and 2)

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

disconnect any power supply.

2. With reference to figures 1 and 2, proceed with the removal of 

three bolts P/N 109-0101-78-5 as follows:

2.1. With reference to the A109K2 Maintenance Manual, unhook the 

four springs P/N 109-0101-56 and the four springs 

P/N 109-0101-57 from the half cover assy P/N 109-0101-98.

2.2. With reference to the A109K2 Maintenance Manual, disconnect

the rotating half scissor assy P/N 109-8110-16 from the main 

rotor scissor fitting assy P/N 109-0110-67.
B.T. 109K-53

Page 4 of 7 

NOTE

To remove the sleeve inside the rotating 

half scissor assy P/N 109-8110-16, use a 

suitable aluminum drift. 

2.3. Cut the lockwire and remove the three bolts 

P/N 109-0101-78-5 with the relevant washers, and the main rotor 

scissor fitting assy P/N 109-0110-67.

2.4. Cut the lockwire and remove the two bolts 

P/N 109-0101-78-3 with the relevant washers, the spring holder 

bracket P/N 109-0104-13 and the half cover assy 

P/N 109-0101-98. 

3. With reference to figures 1 and 2, proceed with the reassembly of 

the parts previously removed from the main rotor hub as follows: 

NOTE

Apply a light coat of corrosion preventive 

compound MIL-PRF-16173 on the mating 

surfaces and on the bolts unthreaded stem. 

3.1. Reinstall the half cover assy P/N 109-0101-98 and the main rotor 

scissor fitting assy P/N 109-0110-67 by means of three new bolts 

P/N 109-0101-78-5, three new washers NAS1149C0463R 

(nominal thickness 1.5 mm) and three new washers 

NAS1149C0432R (nominal thickness 0.8 mm) under the bolts 

head (ref. figure 1). 

3.2. Reinstall the spring holder bracket P/N 109-0104-13 by means of

the previously removed two bolts P/N 109-0101-78-3 with two 

washers AN960C416 or NAS1149C0463R and two washers 

AN960C416L or NAS1149C0432R under the bolts head (ref. 

figure 1). 

3.3. Torque 7.8 to 9.8 Nm the three bolts P/N 109-0101-78-5 and the 

two bolts P/N 109-0101-78-3 and secure them with lockwire 

MS20995C32. 

NOTE

Apply a light coat of corrosion preventive 

compound MIL-PRF-16173 on the head of 

the installed bolts and on the washers. 

3.4. With reference to the A109K2 Maintenance Manual, reconnect 

the rotating half scissor assy P/N 109-8110-16 to the main rotor 

scissor fitting assy P/N 109-0110-67.
B.T. 109K-53

Page 5 of 7

3.5. With reference to the A109K2 Maintenance Manual, connect the 

four springs P/N 109-0101-56 and the four springs

P/N 109-0101-57 to the half cover assy P/N 109-0101-98.

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

5. Record compliance with PART II^ of this Bollettino in the 

helicopter log book.
B.T. 109K-53

Page 6 of 7

FIGURE 1
B.T. 109K-53

Page 7 of 7

FIGURE 2

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.