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BOLLETTINO TECNICO

The technical content of this document is approved

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

N° 412-139

DATE February 19, 2014

REV.

Compliance with

this bulletin is:

SUBJECT: INSPECTION OF THE FLANGED ADAPTER P/N 412-040-622-101 AND 

P/N 412-040-623-101 INSTALLED ON TAIL ROTOR DRIVE SHAFTS.

REASON: Provide the necessary instructions to inspect the above mentioned flanged adapters 

installed on tail rotor drive shafts. 

HELICOPTERS AFFECTED: 

Agusta AB412 helicopters S/N 25801 through 25900 and AB412EP helicopters S/N 25901 

and subs. 

COMPLIANCE: 

Within and not later than 5 flight hours after the issue of this Bollettino, and subsequently 

every 100 flight hours. 

DESCRIPTION: 

AgustaWestland has recently received a report of a crack on a flanged adapter P/N 412-040-

622-101 installed on the tail rotor drive shaft of an AB412EP helicopter. 

The investigation to determine the root causes of the crack on the flanged adapter is in 

progress, then the requirements of this Bollettino could be updated according to the 

investigation results.

This Bollettino is issued in order to prescribe an inspection of the adapter-flanged P/N 412-

040-622-101 and P/N 412-040-623-101 for presence of cracks.

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.

ALERT

ALERT
B.T. 412-139

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MANPOWER REQUIRED: 

Approximately 3 man-hours are required to complete this Bollettino. 

WARRANTY: N.A.

MATERIAL REQUIRED: N.A.

SPECIAL TOOLS: N.A. 

WEIGHT AND BALANCE CHANGE: N.A.

REFERENCES: 

AB412-IPC Illustrated Parts Catalogue 

AB412EP-IPC Illustrated Parts Catalogue 

AB412-MM Maintenance Manual 

PUBBLICATIONS AFFECTED: 

AB 412-MPM Maintenance Planning Manual 

ACCOMPLISHMENT INSTRUCTIONS: 

1. Prepare the helicopter for safe ground maintenance. Disconnect battery and all the electric

power source and/or the external power supply.

2. In accordance with AB412-MM Chapter 65 gain access to the tail rotor drive shaft.

3. Using a 5X magnifying glass and a source light visually inspect the adapter-flanged P/N 412-

040-622-101 and P/N 412-040-623-101 for presence of cracks in proximity of the fixing

bolts (Refer to Figures 1 and 2).

4. If cracks are found, before the next flight remove from the helicopter the affected drive shaft

assy in accordance with AB412-MM Chapter 65 and replace it with a serviceable drive shaft

assy.

5. Report to AgustaWestland Product Support Engineering at the following e-mail address:

absereng@agustawestland.com any case of cracked adapter-flanged and send the affected

parts for investigation.

6. If no cracks are found in accordance with AB412-MM Chapter 65 install the access panel and

close the access doors removed/opened during step 2.

7. Return the helicopter to flight configuration and make an entry in helicopter applicable

documentations to indicate accomplishment of this Bollettino.
B.T. 412-139

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Figure 1 - Crack found during inspection

FLANGED ADAPTER

EXAMPLE OF CRACK 

FOUND DURING 

INSPECTION

AREA TO BE INSPECTED 

ON FLANGED ADAPTER

TYP. 3 PLACES
B.T. 412-139

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Figure 2 – Detail of flanged adapter (on both sides of driveshaft)

FLANGED ADAPTER
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.