EASA AD No.: 2009-0264

EASA Form 110 Page 1/2 

## EASA AIRWORTHINESS DIRECTIVE

AD No.: 2009-0264

Date: 15 December 2009

Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Community, its Member States and of the European third countries that participat e in the activities of EASA under Article 66 of that Regulation. This AD is issued in accordance with EC 1702/2003, Part 21A .3B. In accordance with EC 2042/2003 Annex I, Part M.A.301, the continuing airworthiness of an aircraft shall be ensured by a ccomplishing any applicable ADs. Consequently, no person may opera te an aircraft to which an AD applies, except in accordance with the requirements of that AD unless otherwise specified by the Age ncy [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) exemptio n]. 

### Type Approval Holder’s Name : Agusta S.p.A. Type/Model designation(s) :
A109S helicopters

TCDS Number : EASA.R.005

Foreign AD : Not applicable

Supersedure : None



### ATA 24 Electrical Power – Battery Bus (BATT BUS) Circuit Breaker – Modification

Manufacturer(s): Agusta S.p.A.
Applicability: A109S helicopters, all serial numbers (S/N) up to S/N 22151 included.

Reason: Following a report of an electrical failure on one A109E helicopter, the investigations done by the Type Certific ate holder Agusta have identified the inadequate functioning of the 35 Amperes (Amps) BATT BUS circuit breaker as the reason for the electrical failure. To prevent this unsafe condition, Agusta has developed a BATT BUS circuit breaker modification kit, for the replacement of the 35 Amps circuit breaker with a 50 Amps circuit breaker and the replacement of the wires with oversized ones. EASA AD 2009-0137 required such modifica tion on the affected helicopters. This AD, due to the design commonality between the electrical power generation system of A109E and A109S models, requires installing this modification also on A109S models, in accordance with Agusta Bollettino Tecnico (BT) 109S-35.

Effective Date: 29 December 2009

Required action(s) and Compliance Time(s): Required as indicated, unless accomplished previously: Within 50 flight hours after the effectiv e date of this AD but no later than 30 June 2010, whichever occurs first, modify the fuselage electrical installation P/N 109-0742-52 and the overhead panel electrical installation P/NEASA AD No.: 2009-0264

EASA Form 110 Page 2/2 109-0742-55, installing the BATT BUS circuit breaker modification kit P/N 109-0824-73-107, in accordance with the instructions of Agusta BT 109S-35.
Ref. Publications: Agusta Bollettino Tecnico 109S-35 dated 11 December 2009. The use of later approved revisions of this document is acceptable for compliance with the requirements of this AD.

Remarks: 1. If requested and appropriately substantiated, EASA can approve Alternative Methods of Compliance for this AD. 2. The required actions and the risk allowance have granted the issuance of a Final AD with Request for Comments, postponing the public consultation process after publication. 3. Enquiries regarding this AD should be referred to the Airworthiness Directives, Safety Management & Re search Section, Certification Directorate, EASA. E-mail: ADs@easa.europa.eu

. 4. For any question concerning the tec hnical content of the requirements in this AD, please contact: Agusta S.p.A. Customer Support – Via per Tornavento, 15 21019 Somma Lombardo (VA) – Italy; Phone + 39 0331 940396; Fax: + 39 0331 711180; E-mail: custserv@agustawestland.com

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