EASA AD No.: 2013-0133

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EASA AIRWORTHINESS DIRECTIVE

AD No.: 2013-0133

Date: 28 June 2013

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 participate in the activities of EASA under Article 66 of that 

Regulation.

This AD is issued in accordance with EU 748/2012, 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 applicable ADs. Consequently, no person may operate an 

aircraft to which an AD applies, except in accordance with the requirements of that AD, 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 [EC 216/2008, Article 14(4) exemption].

Design Approval Holder’s Name:

EUROCOPTER

Type/Model designation(s):

AS 350 and AS 355 helicopters

TCDS Number: EASA.R.008, EASA.R.146

Foreign AD: Not Applicable

Supersedure: None

ATA 64 Tail Rotor – Tail Rotor Hub Pitch Horn – Inspection / Replacement

Manufacturer(s): Eurocopter (formerly Eurocopter France, Aerospatiale)

Applicability: AS 350 B, AS 350 BA, AS 350 BB, AS 350 B1, AS 350 B2, AS 350 B3,

AS 350 D, AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, AS 355 N and

AS 355 NP helicopters, all serial numbers, equipped with Tail Rotor Hub (TRH) 

pitch horn assemblies (hereafter called ‘assembly’) Part Number (P/N) 

350A121368.01, P/N 350A121368.02, P/N 350A121368.03, or P/N 

350A121368.04, incorporating TRH pitch horn (hereafter called ‘part’) P/N 

350A121368.XX (where XX stands for two digit dash number excluding 01, 02,

03, and 04 which are reserved for assemblies).

Note: Either the assembly P/N or the part P/N can be marked on the affected 

TRH pitch horns.

Reason: Eurocopter have been informed of a case of crack detection on the yoke of a 

TRH pitch horn. The investigation of this occurrence is on-going and the cause 

has not yet been determined.

This condition, if not detected and corrected, may eventually lead to the failure 

of the two horn yokes, resulting in the loss of the anti-torque function, possibly 

resulting in loss of control of the helicopter.

To address this condition, Eurocopter issued Emergency Alert Service Bulletin 

(ASB) No. 05.00.74 for AS 350 helicopters and ASB No. 05.00.65 for AS 355 

helicopters. Shortly thereafter, these ASBs have been updated and reissued by 

Eurocopter at Revision 1 to clarify that the affected TRH pitch horns can be 
EASA AD No.: 2013-0133

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identified by means of either assembly P/N’s or part P/N’s marked thereon and 

to implement a documentary change to some of tail rotor blade assembly log 

cards.

For the reasons described above, this AD requires repetitive visual inspections 

of the affected TRH pitch horns to detect cracks and, depending on findings, 

replacement with a serviceable assembly.

This AD is considered an interim action and further AD action may follow.

Effective Date: 03 July 2013

Required Action(s) 

and Compliance

Time(s):

Required as indicated, unless accomplished previously:

(1) Initially, within the compliance time indicated in Table 1 of this AD and,

thereafter, at intervals not to exceed 165 flight hours (FH), visually inspect 

both TRH pitch horns in accordance with the instructions of paragraph 

3.B.2.a. of AS350 ASB No. 05.00.74 or AS355 ASB No. 05.00.65, as 

applicable to helicopter type.

Table 1 – Initial inspection

FH accumulated by the TRH 

pitch horn on the effective 

date of this AD

Compliance Time

More than 155 FH since new Within 10 FH after the effective 

date of this AD

Less than or equal to 155 FH 

since new

Before exceeding 165 FH 

since new

(2) If, during any inspection as required by paragraph (1) of this AD, any crack 

is found, before next flight, replace the affected assembly in accordance 

with the instructions of paragraph 3.B.2.b. of AS350 ASB No. 05.00.74 or 

AS355 ASB No. 05.00.65, as applicable to helicopter type.

(3) Replacement of a TRH pitch horn with a serviceable assembly as required 

by paragraph (2) of this AD does not constitute terminating action for the 

repetitive inspections required by paragraph (1) of this AD.

Ref. Publications: Eurocopter AS350 ASB No. 05.00.74 original issue dated 27 May 2013, or Rev. 

1 dated 25 June 2013.

Eurocopter AS355 ASB No. 05.00.65 original issue dated 27 May 2013, or Rev. 

1 dated 25 June 2013.

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 substantiated, EASA can approve 

Alternative Methods of Compliance for this AD.

2. Based on the required actions and the compliance time, EASA have 

decided to issue a Final AD with Request for Comments, postponing the 

public consultation process until after publication.

3. Enquiries regarding this AD should be referred to the Safety Information 

Section, Executive Directorate, EASA. E-mail: ADs@easa.europa.eu.

4. For any question concerning the technical content of the requirements in 

this AD, please contact: EUROCOPTER (STDI) – Aéroport de Marseille 

Provence 13725 Marignane Cedex, France,

Telephone +33 (4) 42 85 97 97, Facsimile +33 (4) 42 85 99 66,

E-mail: Directive.technical-support@eurocopter.com.