BOLLETTINO TECNICO N° 139-306 

The technical content of this document is approved 

under the authority of DOA nr. EASA.21J.005 DATE December 12, 2012

REV. /

Compliance with 

this Bulletin 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.

Page 1 of 6 

SUBJECT: NOSE LANDING GEAR, INSPECTION OF ARMS PIN INSTALLATION.

REASON: to check the correct installation of Nose Landing Gear (NLG) pins 

P/N 1661-0001. 

HELICOPTERS AFFECTED: all the following AB139/AW139 helicopters equipped 

with NLG assy P/N 3G3220V00133 or P/N 3G3220V00135: 

 from S/N 31005 to S/N 31157 (except S/N 31007); 

 from S/N 31201 to S/N 31398; 

 from S/N 31400 to S/N 31440 (except S/N 31413, S/N 31415, S/N 31417, S/N 

31420, S/N 31422 thru S/N 31424, S/N 31427, S/N 31429 thru S/N 31431, 

S/N 31433, S/N 31434 and S/N 31439). 

 from S/N 41001 to S/N 41023; 

 from S/N 41201 to S/N 41293 (except S/N 41276, S/N 41287, S/N 41289, S/N 

41290, S/N 41291 and S/N 41292); 

 from S/N 41300 to 41310 (except S/N 41302, S/N 41304, S/N 41305, S/N 

41306, S/N 41309). 

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.

AgustaWestland S.p.A

Via Giovanni Agusta, 520

21017 Cascina Costa di Samarate (VA) Italy

Tel.: +39 0331 229111 - Fax: +39 0331 229605/222595
B.T. 139-306

Page 2 of 6 

COMPLIANCE: within fifty (50) flight hours or one (1) month from receipt of this 

Bollettino, whichever comes first.

DESCRIPTION: events of incorrect pin installations have been verified on some 

aircrafts in service, causing a prestress condition on the pin flange. This Bollettino 

provides the instruction to perform a one-off visual inspection to confirm correct pin 

installation. 

REQUIRED MANPOWER: to comply with this Bollettino Tecnico one (1) 

Maintenance-Man-Hour (MMH) is deemed necessary: 

Man-hours are based on hands-on time and can change with personnel and 

facilities available. 

WARRANTY: N.A.

REQUIRED MATERIALS: the following consumable materials are necessary to 

accomplish this Bollettino: 

SPEC./AW Code Number DESCRIPTION Q.ty NOTES

Commercial Ardrox AV15, Corrosion 

Inhibiting Compound (C343)

AR Local supply

Refer to Aircraft Material Data Information (AMDI) and Illustrated Parts Data (IPD) 

for the materials and consumable materials required to comply with the Data 

Modules referenced in this Bollettino Tecnico. 
B.T. 139-306

Page 3 of 6 

SPECIAL TOOLS: the following special tools are required to accomplish this 

Bollettino:

P/N DESCRIPTION Q.ty REMARKS

3G0705G00231 or 

approved alternative

Jack, hydraulic (HA-01-00) 4 Local supply

Refer to Illustrated Tools and Equipment Publication (ITEP) for other special tools 

required to comply with the AMP Data Modules referenced in this Bollettino 

Tecnico. 

WEIGHT AND BALANCE CHANGES: N.A. 

REFERENCES:

 AW139 Aircraft Corrosion Control Publication (ACCP) 

 AW139 Aircraft Material Data Information (AMDI) 

 AW139 Aircraft Maintenance Publication (AMP) 

 AW139 Illustrated Tools and Equipment Publication (ITEP) 

PUBLICATIONS AFFECTED:

 AW139 Aircraft Maintenance Publication (AMP) 

COMPLIANCE INSTRUCTIONS:

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

all electrical power sources and/or the external power supply. Refer to AMP, see 

DM n° 39-A-00-20-00-00A-120A-A.

NOTE

Step 2 and step 7 are applicable only to helicopters 

equipped with Kit NLG doors P/N 3G5280F00111, 

P/N 4G5280F00111 or P/N 4G5280F00112. 

2. Open NLG doors, as necessary, to get access to the pins installation (1) on NLG 

arms. Refer to AMP, see DM n° 39-A-52-81-00-00A-540A-K.
B.T. 139-306

Page 4 of 6 

3. Do a visual inspection of the pin installations (1) on both left and right arms as 

follows: 

3.1 Check for the proper installation of the following hardware: 

 bolt (2); 

 washer (3), under bolt head; 

 washer (4), between NLG arm and pin (5); 

 pin (5); 

 washer (6), under nut; 

 nut (7); 

 cotter pin (8). 

3.2 Make sure that the washer (4) is correctly installed as shown in detail A.

3.3 If washer installation is compliant with detail A, go to step 5, otherwise

perform following step 4.

4. If on one or both sides the washer (4) P/N NAS1149C0563R is not present or the 

installation is different from the one prescribed in detail A, do as follows: 

4.1 Lift the helicopter on jacks. Refer to AMP, see DM n° 39-A-07-11-00-00A000A-A.

4.2 Remove cotter pin (8), nut (7), washer (6), bolt (2), washer (3), pin (5) and 

washer (4), if present. Discard the cotter pin (8).

4.3 Do a visual inspection of the bolt (2) and the nut (7) for corrosion. If you find 

signs of corrosion, replace them installing pin (5) at steps 4.6 and 4.7.

4.4 Do a visual inspection of the pin (5) for corrosion and condition. If you find 

signs of corrosion and/or damage do as follows: 

CAUTION

Make sure not to damage the surface of the pin, 

removing corrosion and/or damage at following step 

4.4.1. 

4.4.1 Remove the light corrosion and/or damage with an abrasive stone or 

glass fibre brush. Refer to ACCP, DM n° 39-A-20-40-00-00A-010A-E.

4.4.2 Measure the pin diameter after corrosion and/or damage removal. 

4.4.3 Discard the pin if the diameter measured at step 4.4.2 is less than 

25.359 mm (0.9984 in) and replace it with a new one at steps 4.6 and 

4.7. 
B.T. 139-306

Page 5 of 6 

4.5 Do a visual inspection of the pin (5) for cracks as follows: 

4.5.1 Do a visual inspection of the pin (5) for cracks. If you find any cracks, 

go to steps 4.6 and 4.7 to replace the pin (5). 

4.5.2 Do a detailed inspection for surface cracks on the pin (5) flange using 

dye penetrant. Refer to AMP, see DM n° 39-A-60-40-00-01A-351A-D. 

If you find any cracks, replace the pin (5) following the steps 4.6 and 

4.7. 

4.6 Apply one coat of Ardrox AV15 Corrosion Inhibiting Compound (C343) on the 

pin (5), the bolt (2) and the nut (7).

4.7 Reinstall the pin (5) referring to the applicable steps of AMP DM n° 39-A-32-

21-01-00A-720A-A.

4.8 Repeat steps 4.2 thru 4.7 on the other side if the washer (4) was not present 

or the installation is different from the one prescribed in detail A. 

4.9 Lower the helicopter on the ground. Refer to AMP, see DM n° 39-A-07-11-

00-00A-000A-A.

4.10 Skip steps 5 and 6 and go to step 7. 

CAUTION

Do not remove the bolt (2) to perform the visual 

inspection at step 5. 

5. Do a visual inspection of the bolt (2) head and the nut (7) for corrosion (bolt 

removal is not required). If you find signs of corrosion, do as follows:

5.1 Lift the helicopter on jacks. Refer to AMP, see DM n° 39-A-07-11-00-00A000A-A.

5.2 Replace the defective item referring to the applicable steps of AMP DM n° 

39-A-32-21-01-00A-720A-A.

5.3 Lower the helicopter on the ground. Refer to AMP, see DM n° 39-A-07-11-

00-00A-000A-A.

6. Apply one coat of Ardrox AV15 Corrosion Inhibiting Compound (C343) on the bolt 

(2) head and the nut (7).

7. Close NLG doors opened at step 2. Refer to AMP, see DM n° 39-A-52-81-00-00A740A-K.

8. Return helicopter to flight configuration and record for compliance with this 

Bollettino on the helicopter logbook.
B.T. 139-306

Page 6 of 6 

Figure 1 
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.