EASA AD No.: 2009-0029

EASA Form 110 Page 1/3 

## EASA AIRWORTHINESS DIRECTIVE

AD No.: 2009-0029

Date: 12 February 2009

Note: This Airworthiness Directive (AD) is i ssued 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 participate 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 accomplishing any app licable ADs. Consequently, no person may opera te an aircraft to which an Airworthiness Directive applies, except in accordance with the requirements of that Airworthiness Directiv e unless otherwise specified by the Agency [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [E C 216/2008, Article 14(4) exemption]. 

### Type Approval Holder’s Name :

EUROCOPTER Type/Model designation(s) :
AS 355 helicopters

TCDS Number : EASA.R.146

Foreign AD : Not applicable

Supersedure: This AD supersede s EASA AD 2008-0120 dated 27 June 2008



### ATA 55 Stabilizers – Upper and Lower Fin Attachment Fitting - Inspection / Modification / Replacement

Manufacturer(s): EUROCOPTER (formerl y EUROCOPTER FRANCE, AEROSPATIALE).

Applicability: AS 355 E, F, F1, F2 and N helicopters, all serial numbers, if fitted with the following upper and lower fins to which modification (MOD) 073330 has not been embodied:

Upper fin assembly part number (P/N):

355A14-0522-00XX 355A14-0522-01XX

355A14-0522-02XX 355A14-0522-03XX

355A14-0522-13XX 355A14-0522-14XX

355A14-0522-15XX

Lower fin assembly P/N:

355A14-0521-00XX 355A14-0521-01XX

355A14-0521-02XX 355A14-0521-03XX

Reason: Some cracks have been discovered in the spar of the upper fin on AS 355 N helicopters. The growth of a crack in a fin attachment spar, if not corrected, may lead to the failure of the spar and the loss of the fin.EASA AD No.: 2009-0029

EASA Form 110 Page 2/3 EASA AD 2008-0120 rendered mandat ory MOD 073330 introduced by EUROCOPTER AS 355 Alert Service Bulletin (ASB) No. 55.00.12, whose purpose
was: - to reduce the risk of forced fitting by increasing the diameter of the holes for the bolts on the lower and upper fin attachment fittings on the tail boom, and - to improve the fatigue strength of upper and lower fin attachment by replacing bolts and washers currently installed with special bolts and special washers. Thereafter, EUROCOPTER issued Revision 1 of ASB No. 55.00.12 to add new upper and lower fin assembly part numbers in the applicability. In addition, EASA AD 2008-0120 whic h superseded EASA AD 2006-0097R1 omitted to retain the initial action and repetitive checks required by EASA AD 2006-0097R1.
For the reasons described above, this AD retains t he requirements of EASA AD 2008-0120, which is superseded, and adds new upper and lower fin assembly part numbers in the applicability as well as repetitive checks until the accomplishment of MOD 073330.
Effective Date: 26 February 2009

Required action(s) and Compliance Time(s): Required as indicated, unless accomplished previously: 1. For helicopters with upper and lower fins pre MOD 073288 : 1.1. For helicopters having accumulated less than 110 flying hours (FH) after 20 August 2006, the effect ive date of AD 2006-0097R1: Within the next 110 FH after 20 August 2006, the effective date of AD 2006-0097R1, replace the upper fin and lower fin attachment screws in compliance with the instructions s pecified in paragraph (§) 2.B.2. of EUROCOPTER AS 355 ASB No. 55.00.11 Revision 2 (MOD 073288). 1.2 For helicopters having accumulated more than 110 FH after 20 August 2006, the effective date of AD 2007-0097R1: Within 15 FH after the effective date of this AD, replace the upper fin and lower fin attachment screws in compliance with the instructions specified in § 2.B.2. of EUROCOPTER AS 355 ASB No. 55.00.11 Revision 2 (MOD 073288). 1.3 At intervals not exceeding 110 FH , check the tightening torque of the upper fin attachment screws and chec k the upper fin reinforcement splice for cracks and loosened rivets in compliance with the instructions specified in § 2.B.3 of EUROCOPTER AS 350 ASB 55.00.11 Revision 2. 1.4 In case of cracks, loosened rivets in the reinforcement splice or if the tightening torque of one or both of the attachment screws is less than 80% of the minimum torque value, before further flight, apply the associated corrective actions in accordance with the instructions of § 2.B.3.a.1, 2.B.3.a.2. or 2.B.3.a.3. (as applicable), of EUROCOPTER AS 350 ASB 55.00.11 Revision 2.

2. For helicopters with upper and lower fins post MOD 073288: 2.1 For helicopters having accumulated less than 110 FH since the latest check performed in accordance wi th § 2.B.3 of EUROCOPTER AS 350 ASB 55.00.11 Revision 0 or Revision 1 or Revision 2: Within 110 FH after the latest check performed in accordance with § 2.B.3 of EUROCOPTER AS 350 ASB 55.00.11 Revision 0 or Revision 1 or Revision 2, check the tightening torque of the upper fin attachment screws and check the upper fin reinforcement splice for cracks and loosened rivets in compliance with the instructions specified in § 2.B.3 ofEASA AD No.: 2009-0029

EASA Form 110 Page 3/3 EUROCOPTER AS 350 ASB 55.00.11 Revision 2. Thereafter repeat these checks at intervals not exceeding 110 FH. 2.2 For helicopters having accumulated more than 110 FH since the latest check performed in accordance wi th § 2.B.3 of EUROCOPTER AS 350 ASB 55.00.11 Revision 0 or Revision 1 or Revision 2: Within 15 FH after the effective date of this AD, check the tightening torque of the upper fin attachment screws and check the upper fin reinforcement splice for cracks and loosened rivets in compliance with the instructions specified in § 2.B.3 of EUROCOPTER AS 350 ASB 55.00.11 Revision 2. Thereafter repeat these checks at intervals not exceeding 110 FH. 2.3 In case of cracks, loosened rivets in the reinforcement splice or if the tightening torque of one or both of the attachment screws is less than 80% of the minimum torque value, apply corrective actions in accordance with the instructions of § 2.B.3.a.1, 2.B.3. a.2. or 2.B.3.a.3. (as applicable) of EUROCOPTER AS 355 ASB 55.00.11 Revision 2.

3. For helicopters with upper and lower fins pre MOD 073330: Unless already accomplished in accordance with § 1 of EASA AD 2008-0120, no later than 31 March 2009, remove the fins, modify the lower and upper fittings on tail boom by increasing the diameter of the holes for the bolts and replace bolts P/N 22126BV060032L and washers P/N 23112AG060LE with special bolts P/N 350A23-4016-20 and special washers P/N 350A23- 4017-22 in accordance with EUROCOPTER AS 355 ASB No. 55.00.12. Revision 1 (MOD 073330). Compliance with the requirements of § 3. of this AD is considered as:

- acceptable to comply with paragraphs 1.1 and 1.2 of this AD, - terminating action for the repetitive checks required by paragraphs 1.3, 2.1 and 2.2 of this AD.

4. After 31 March 2009, no person shall install on any helicopter spare upper and lower fins with part numbers as listed in the Applicability of this AD, unless MOD 073330 has been accomplished.

Ref. Publications: EUROCOPTER AS 355 Alert Service Bulletin No. 55.00.11 Revision 2 dated 28 February 2008; EUROCOPTER AS 355 Alert Service Bulletin No. 55.00.12 Revision 1 dated 05 January 2009. The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD.

Remarks: 1. If requested and appropriately subs tantiated, EASA can approve Alternative Methods of Compliance for this AD. 2. The required actions and the risk a llowance 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 & Research Secti on, Certification Directorate, EASA. E-mail: ADs@easa.europa.eu

. 4. For any question concerning the technica l content of the requirements in this AD, please contact: EUROCOPTER (STDI) – Aéroport de Marseille Provence 13725 Marignane Cedex – France. Tel: +33(0)4 42 85 97 97 – Fax: +33(0)4 42 85 99 66, E-mail: Directive.technical-support@eurocopter.com

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