TRANSLATION OF

BOLLETTINO TECNICO N°109EP-128

The technical content of this document is approved 

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

DATE January 21, 2013 

REV. A May 28, 2013xx, 2011

Compliance with 

This bollettino is: 

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

 If ownership of aircraft has changed, please forward to new owner. 

 XX Page 1 of 7

SUBJECT:INSPECTION OF GLEASON CROWN P/N 109-0403-07-103. 

REASON: Introduction of additional inspections of Gleason crown 

P/N 109-0403-07-103. 

HELICOPTERS AFFECTED:

All the Agusta helicopters A109 E that install the main transmission P/N 

109-0400-03-109 up to S/N L48 included and have not applied the 

Bollettino Tecnico n°109EP-126. 

NOTE 1

Serial Numbers follow alphabetic order for 

the letter and increasing numbering. 

NOTE 2

For main transmissions S/N L49 and 

subsequent, which carried out maintenance 

activity, check on the pertinent 

documentation that Gleason Crown Assy 

P/N 109-0401-27-107 has not been replaced 

with a Gleason crown assy P/N 

109-0401-27-101/-109 (these installing the 

Gleason Crown P/N 109-0403-07-103 

subject to this BT). 

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. 109EP-128 

Page 2 of 7 

NOTE 3

All the helicopter which have already 

performed the magnetic particle inspection 

required by the first edition of this BT are not 

required to repeat it up to the overhaul. 

COMPLIANCE:

Flight Hours (FH) accumulated 

by the transmission: 

P/N 109-0400-03-109, 

on the effective date of this 

Bollettino 

Compliance time

Less or equal to 2400 FH Before exceeding 200 FH 

after the 2400 FH 

accumulated by the 

transmission. 

More than 2400 and less than 

3000 FH 

Before exceeding the next 

200 FH accumulated by 

the transmission. 

More or equal to 3000 FH and 

less than 3200 FH 

Perform the scheduled 

special inspection per the 

Maintenance Manual at 

3200 FH accumulated by 

the transmission. 

More than 3200 and less than 

4000 FH 

Before exceeding 200 FH 

after the 4000 FH 

accumulated by the 

transmission. 

More than 4000 FH and less than 

4600 FH 

Before exceeding the next 

200 FH accumulated by 

the transmission. 

More or equal to 4600 FH Before exceeding the 

overhaul limit (4800 FH) 

and then each 1600 FH 

after each TBO. 

DESCRIPTION:

On Agusta A119 helicopter, during the execution of the main 

transmission P/N 109-0400-05-103 overhaul, a crack on Gleason crown 

P/N 109-0403-07-103 was found. 

The investigations show that the crack was originated from the bottom of 

one of 40 threaded holes and that the Gleason crown installed on the 

A
B.T. 109EP-128 

Page 3 of 7 

main transmission object of this Bollettino, could be subject to similar 

problem. 

This Bollettino therefore requires the introduction of two unscheduled 

inspection of the Gleason crown P/N 109-0403-07-103; One before the 

current scheduled 3200 FH, and one between the current scheduled 

3200 FH and 4800 FH inspections and the introduction of one repetitive 

inspection every 1600 flight hours, after the achievement of the each 

overhaul limit, scheduled at 4800 FH. In case of crack is found on 

Gleason crown P/N 109-0403-07-103, it is required to replace it with a 

new support assy Gleason crown P/N 109-0401-27-107 (welded to the 

mast support, therefore it does not have the 40 threaded holes) by mean 

application of BT 109EP-126. 

REQUIRED MANPOWER:

An estimated 24 manpower hours are required for compliance with this 

Bollettino. 

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 AgustaWestland S.p.A. upon Customer’s request, with 

the exception for Consumable materials and Tools; all the parts required 

after the “Compliance date” will be dispatched on charge basis for the 

Customer. 

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

AgustaWestland S.p.A. Warranty Administration the Bollettino Tecnico 

Compliance form attached to this Bollettino duly completed in all its parts, 

and relevant W.M.M. form ( (W)arranty Claim (M)aintenance Work Order 

(M)alfunction Report ). 

REQUIRED MATERIALS:

N.A. 

SPECIAL TOOLS:

N.A. 

WEIGHT AND BALANCE CHANGES: 

N.A. 

REFERENCES:

A 109E Maintenance Manual; 

A119/A109 Series Overhaul Manual. 

PUBLICATIONS AFFECTED:

A 109E Maintenance Planning Manual; 

A 109E Maintenance Manual. 

A119/A109 Series Overhaul Manual. 

COMPLIANCE INSTRUCTIONS:

A
B.T. 109EP-128 

Page 4 of 7 

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

disconnect any power supply in accordance with the instructions 

given in the A 109E Maintenance Manual. 

2. Gain access to Main transmission area removing the 

Transmission Front Fairing and the Transmission Rear fairing in 

accordance with the procedure given in the A 109E Maintenance 

Manual. 

3. Verify that the S/N of the main transmission 

P/N 109-0400-03-109 is S/N “L48” included and previous. 

NOTE 1

Serial Numbers follow alphabetic order for 

the letter and increasing numbering. 

NOTE 2

For main transmissions S/N L49 and 

subsequent, which carried out maintenance 

activity, check on the pertinent 

documentation that Gleason Crown Assy 

P/N 109-0401-27-107 has not been replaced 

with a Gleason crown 109-0403-07-103 

subject to this BT. 

4. If the main transmission P/N 109-0400-03-109 is S/N L49 and 

subsequent, and the Gleason Crown Assy P/N 109-0401-27-107 

has not been replaced with a Gleason crown 109-0403-07-103, 

perform paragraph n° 10. 

5. If the main transmission P/N 109-0400-03-109, is S/N L48 

included and previous and if S/N is L49 and subsequent, and the 

Gleason Crown Assy P/N 109-0401-27-107 has been replaced 

with a Gleason crown 109-0403-07-103, proceed with the 

following steps: 

5.1. In accordance with the instructions given in the A 109E 

Maintenance Manual, remove the main rotor blades and the 

main rotor head. 

5.2. In accordance with the instructions given in the 

A 109E Maintenance Manual remove the main transmission 

from the helicopter. 

6. Remove and perform the magnetic particle inspection of the 

Gleason crown as shown in A 109E Maintenance Manual and 

Annex 1. 

NOTE

During the execution of Gleason crown 

magnetic particle inspection, look at the 
B.T. 109EP-128 

Page 5 of 7 

presence of cracks at the bottom of threaded 

holes and in the areas adjacent to them. 

7. If after inspection cracks are found, apply BT n° 109EP-126: 

8. If after the inspection no cracks are found, perform all the 

operations necessary to return the transmission in service as 

shown in the A 109E Maintenance Manual. 

9. In accordance with the instructions given in the A 109E 

Maintenance Manual, reinstall the Main rotor Head and n°4 

Blades. 

10. In accordance with the instructions given in the A 109E 

Maintenance Manual reinstall the Transmission Front Fairing and 

the Transmission Rear fairing. 

11. Return the helicopter to a ready-to-flight condition. 

12. Record compliance with this Bollettino in the helicopter log book. 

 
B.T. 109EP-128 

Page 6 of 7 

MAGNETIC PARTICLE INSPECTION (ASTM

A. General. 

(1) Consumable materials: 

WARNING: THE CONSUMABLE MATER

PREFIXED BY «D» ARE DANGEROUS MATERIALS.

BEFORE USE, MAKE SURE TO KNOW

INSTRUCTIONS PRINTED ON:

— THE LABEL ON THE CON

— THE MATERIAL SAFETY 

— THE LOCAL SAFETY REG

ALSO MAKE SURE THAT THE APPLICABLE FIRST

— (D) Paint remover. 

— (D) MEK 

— Abrasive pad . 

— (D) Aliphatic naphtha 

— Lubricating. 

(2) Other recommendations: 

NOTE: Refer to deals with the items in question for magnetic inspection data.

B. Strip paint finish from the part with paint remover. Remov

sealant from the surfaces with a plastic scraper and MEK, or abrasive pad .

C. Vapor degrease the part with aliphatic naphtha. Surfaces to be inspected must be free from 

oil, dirt, paint, corrosion, or other surface films, co

defects or give false indications.

NOTE: All magnetic particle inspections must be conducted by the continuous process using the 

longitudinal and circular methods. The inspection process must be in accordance with th

manufacturer's equipment instructions.

D. Circular magnetization method.

(1) Put the part to be inspected between the contact plates of the magnetizing unit so that 

electrical current passes through the part or through an electrical conductor that passes

through the part. 

The electrical current used to produce the magnetic flux shall be 240 to 310 Ampere per 

cm of external diameter of the part. Proceed as follows:

a. All contact areas must be clean and wet to prevent arcing or overheating of the part to 

tested. 

b. The central electrical conductor must be as near the size of the openings as practicable.

c. A central electrical conductor must be used when the length of a part is very small as 

compared to the diameter or when the wall thickness is very 

diameter. 

d. Sharper defect indications are desired on the inner diameter of the part.

e. Very small parts which are difficult to place between the heads or on a central conductor 

shall be inspected with the longitudinal method.

E. Longitudinal magnetization method.

(1) The part must be magnetized by placing the part in a coil and passing an electrical current 

through the coil. The number of ampere

determined by the formula: 

ANNEX 1

SPECTION (ASTM-E-1444) 

THE CONSUMABLE MATERIALS THE NOMENCLATURE OF WHICH IN THE LI

DANGEROUS MATERIALS.

E TO KNOW THE SAFETY PRECAUTIONS AND FIRST AID 

ON:

THE LABEL ON THE CONTAINER THE MATERIAL WAS SUPPLIED IN

THE MATERIAL SAFETY DATA SHEET 

THE LOCAL SAFETY REGULATIONS. 

THE APPLICABLE FIRST AID MATERIALS ARE AV

Refer to deals with the items in question for magnetic inspection data.

. Strip paint finish from the part with paint remover. Remove any remaining finish or aged 

sealant from the surfaces with a plastic scraper and MEK, or abrasive pad .

. Vapor degrease the part with aliphatic naphtha. Surfaces to be inspected must be free from 

oil, dirt, paint, corrosion, or other surface films, coatings, or conditions which could mask 

defects or give false indications.

All magnetic particle inspections must be conducted by the continuous process using the 

longitudinal and circular methods. The inspection process must be in accordance with th

manufacturer's equipment instructions.

. Circular magnetization method.

(1) Put the part to be inspected between the contact plates of the magnetizing unit so that 

electrical current passes through the part or through an electrical conductor that passes

The electrical current used to produce the magnetic flux shall be 240 to 310 Ampere per 

cm of external diameter of the part. Proceed as follows:

a. All contact areas must be clean and wet to prevent arcing or overheating of the part to 

b. The central electrical conductor must be as near the size of the openings as practicable.

c. A central electrical conductor must be used when the length of a part is very small as 

compared to the diameter or when the wall thickness is very small compared to the 

d. Sharper defect indications are desired on the inner diameter of the part.

e. Very small parts which are difficult to place between the heads or on a central conductor 

shall be inspected with the longitudinal method.

ngitudinal magnetization method.

(1) The part must be magnetized by placing the part in a coil and passing an electrical current 

through the coil. The number of ampere-turns used to magnetize the part must be 

E OF WHICH IN THE LIST IS 

NS AND FIRST AID 

WAS SUPPLIED IN

AID MATERIALS ARE AVAILABLE. 

e any remaining finish or aged 

sealant from the surfaces with a plastic scraper and MEK, or abrasive pad .

. Vapor degrease the part with aliphatic naphtha. Surfaces to be inspected must be free from 

atings, or conditions which could mask 

All magnetic particle inspections must be conducted by the continuous process using the 

longitudinal and circular methods. The inspection process must be in accordance with the 

(1) Put the part to be inspected between the contact plates of the magnetizing unit so that 

electrical current passes through the part or through an electrical conductor that passes

The electrical current used to produce the magnetic flux shall be 240 to 310 Ampere per 

a. All contact areas must be clean and wet to prevent arcing or overheating of the part to be 

b. The central electrical conductor must be as near the size of the openings as practicable.

c. A central electrical conductor must be used when the length of a part is very small as 

small compared to the 

e. Very small parts which are difficult to place between the heads or on a central conductor 

(1) The part must be magnetized by placing the part in a coil and passing an electrical current 

turns used to magnetize the part must be 
B.T. 109EP-128 

Page 7 of 7 

where: 

l = length of parts; 

d = diameter of the part; 

and the l/d ratio is between 9 and 3. 

When the part has a l/d ratio greater than 9 use 5000 ampere-turns and magnetize the 

part several times to ensure complete coverage of the part. 

A maximum of 15000 ampere-turns shall be used on any part with a l/d ratio less than 3. 

NOTE 1: Ampere-turn defines the amperage that passes through the coil multiplied by the number 

of turns in the coil. 

NOTE 2: The part should be placed off-center of the coil with the long axis of the part parallel to the 

long axis of the coil unless otherwise specified. 

F. Application of magnetic particles in suspension - Continuous method. 

(1) Prepare the solution; to do this, mix the magnetic particle powder to the suspension. 

(2) Apply the magnetic particles in suspension; to do this, spray the liquid through a tube so 

as to obtain complete coverage of the surface under examination. 

(3) Close the magnetization circuit 1/5 to 1/2 second while the part is covered with a film of 

liquid as necessary to give adequate indication. 

(4) Discontinue spraying and leave parts to drip for several seconds. 

NOTE: The part on which a film of liquid remains must be rinsed, magnetized and sprayed with 

the liquid per step (1). 

(5) After inspection, acceptable parts shall be cleaned and demagnetized. Check parts with a 

field indicator to ensure demagnetization. 

(6) Apply a film of lubricating oil on the parts to prevent corrosion. 

G. Inspect parts with black light. 

NOTE: Surface or subsurface defects will be revealed by magnetic particle accumulation around 

the defect. 

Recommended magnetization currents for magnetic particle inspection. 

NOMENCL. INSP. 

AREA 

CIRCULAR MAGNETISM LONGITUDINAL

MAGNETISM 

AMP. 

CENTR COND 

DIA 

(mm) 

INSP. 

AXIS NOTE INSP. AREA 

AMP. 

x 

TURNS 

NOTE 

Gleason 

crown 

Minor I.D. 

Major O.D. 

2000 

 

3400 

50 

Thread-ing bar 

(INSU- LATED) 

Longit. [1] Entire 

item 15000 [4] 

NOTE 

[1] Rotate part by 60° and repeat the inspection at 6 points. 

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.