EASA AD No.: 2013-0029

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EASA AIRWORTHINESS DIRECTIVE

AD No.: 2013-0029

Date: 08 February 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 21.A.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 B3 helicopters

TCDS Number: EASA.R.008

Foreign AD: Not applicable

Supersedure: This AD supersedes EASA Emergency AD 2012-0217-E dated 19 October 2012.

ATA 64

Rotorcraft Flight Manual – Section Limitations – Amendment

Tail Rotor – Laminated Half-Bearings – Inspection / Replacement /

Modification

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

Applicability: AS 350 B3 helicopters, all serial numbers, if modified in production by 

incorporating Eurocopter modification (MOD) 07 5601, except those helicopters 

that have been modified by incorporating Eurocopter MOD 07 5606 in 

production.

Note: MOD 07 5601 is an integral part of a specific AS 350 B3 model 

configuration, commercially identified as “AS350B3e” and is not fitted on AS

350 B3 model helicopters of other configurations.

Reason: Premature failures of laminated half-bearings, Part Number (P/N) 704A33-633-

261 (supplier P/N 5791530004), installed in tail rotors, were detected on AS 350 

B3 helicopters in AS350B3e configuration. Three cases of vibrations originating 

from the tail rotor were also reported, detected in flight on affected helicopters, 

following which precautionary landings were performed. The cause of vibration 

has been identified as failure of the laminated half-bearings.

Subsequently, an accident occurred involving an AS 350 B3 helicopter in 

AS350B3e configuration. During the affected flight, the pilot felt strong 

vibrations originating from the tail rotor before losing control of the helicopter. It 

was found that, due to their deterioration, the laminated half-bearings were 

twice replaced on this helicopter prior to the accident.

This condition, if not detected and corrected, could lead to failure of the tail 
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rotor, possibly resulting in loss of control of the helicopter.

To address this unsafe condition, Eurocopter issued AS350 Emergency Alert 

Service Bulletin (ASB) No. 01.00.65 for the affected AS 350 B3 helicopters in

this particular configuration.

Consequently, EASA issued Emergency AD 2012-0207-E to require changes to 

the Rotorcraft Flight Manual (RFM), imposing limitations of the flight envelope in 

order to reduce the dynamic loads on the tail rotor, and a one-time pre-flight 

inspection, a one-time ALF check inspection (including tail rotor disassembly), 

and repetitive post-flight inspections of the laminated half-bearings to detect 

damage and, depending on findings, replacement of all 4 laminated halfbearings.

After that AD was issued, a discrepancy was found where, under specific 

altitude and temperature conditions, the new airspeed limitation (defined in True 

Airspeed – TAS) and the information on one of the two related labels (defined in 

Indicated Airspeed – IAS) were not compatible. Additionally, Eurocopter defined 

a new Engine Health Check (EHC) procedure which was compatible with the 

new airspeed limitation.

To address the discrepancy described above and to publish the new EHC 

procedure, Eurocopter issued AS350 EASB No. 01.00.65 revision 1.

Prompted by these findings and actions, EASA issued AD 2012-0217-E 

retaining partially the requirements of EASA AD 2012-0207-E, which was 

superseded, and introducing a new airspeed limitation (defined in IAS only) and 

introducing the new EHC procedure to replace the one incorporated in the 

AS350B3e RFM.

Since EASA AD 2012-0217-E was issued, Eurocopter designed a new 

modification MOD 07 5606, which restores the tail rotor dynamic load level 

similar to that on helicopters pre MOD 07 5601, thereby eliminating the modified 

loading conditions of laminated half-bearings which caused the intensified 

deterioration and reported failures.

For the reasons described above, this new AD retains the requirements of 

EASA AD 2012-0217-E, which is superseded, and requires incorporation of 

MOD 07-5606 as a terminating action.

Effective Date: 01 March 2013

Required Action(s) 

and Compliance

Time(s):

Required as indicated, unless accomplished previously:

(1) Before next flight after 05 October 2012 [the effective date of EASA AD 

2012-0207-E], install the VNE IAS limit vs. flight altitude placard (specified 

as Label (2) in Eurocopter AS350 ASB No. 01.00.65) on the instrument 

panel, in full view of the pilot and co-pilot, in accordance with the 

instructions of paragraph 3.B.1 of Eurocopter AS350 ASB No. 01.00.65.

(2) Before next flight after 19 October 2012 [the effective date of EASA AD 

2012-0217-E], accomplish the following actions concurrently:

(2.1) Remove the VNE limitation placard (specified as Label (1) in 

Eurocopter AS350 ASB No. 01.00.65), as previously required by 

paragraph (1) of EASA AD 2012-0207-E, from the helicopter, and

(2.2) Replace the RFM specific pages, as previously required by

paragraph (1) of EASA AD 2012-0207-E, with specific pages 

containing the temporary VNE limitation, emergency procedure for inflight vibrations felt in the pedals and temporary EHC procedure, 

which are provided in Section 4 Appendix of Eurocopter AS350 ASB 

No. 01.00.65 revision 1.

Concurrent with making the changes as required by paragraphs (1) and (2)

of this AD, inform all flight crews and, thereafter, operate the helicopter 

accordingly.
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(3) Before next flight after 05 October 2012 [the effective date of EASA AD 

2012-0207-E], and thereafter, after each flight, without exceeding 3 flight 

hours between two consecutive inspections, visually inspect the laminated 

half-bearings in accordance with the instructions of paragraph 3.B.2 of 

Eurocopter AS350 ASB No. 01.00.65.

(4) If, during any inspection as required by paragraph (3) of this AD, any

deficiencies are found, defined as “Deterioration requiring replacement” in 

paragraph 3.B.3.a of Eurocopter AS350 ASB No. 01.00.65, before next 

flight, replace all 4 laminated half-bearings in accordance with the 

instructions of AS350B3 Maintenance Manual Work Cards No. 64-10-00, 

paragraph 4-3 and No. 64-10-00, paragraph 4-4.

(5) During the next ALF check after 05 October 2012 [the effective date of 

EASA AD 2012-0207-E], disassemble the tail rotor in accordance with the 

instructions of paragraph 1.E.2.a.4 of Eurocopter AS350 ASB No. 01.00.65

and visually inspect the laminated half-bearings for deficiencies. If during 

this check, any separation, cracks, or extrusions in the elastomer are found 

in any bearing, before next flight, replace all 4 laminated half-bearings in 

accordance with the instructions of AS350B3 Maintenance Manual Work 

Cards No. 64-10-00, paragraph 4-3 and No. 64-10-00, paragraph 4-4.

Note: Paragraph 3.B.3.b of Eurocopter AS350 ASB No. 01.00.65 instructs to 

replace only those half-bearings found damaged. Instead, this AD requires 

replacement of all 4 laminated half-bearings.

(6) Within 5 months after the effective date of this AD, modify the helicopter in 

accordance with instructions of Eurocopter AS350 SB No. 01.00.66 (MOD 

07 5606).

(7) Modification of a helicopter as required by paragraph (6) of this AD 

constitutes terminating action for the repetitive inspections of the laminated 

half-bearings as required by paragraphs (3) and (5) of this AD for that 

helicopter. After modification of a helicopter as required by paragraph (6) of 

this AD, the operating limitations placard and RFM procedures as 

introduced, respectively, by paragraphs (1) and (2.2) of this AD, are no 

longer required and must be removed from that helicopter.

Ref. Publications: Eurocopter AS350 Emergency ASB No. 01.00.65 original issue dated 04 

October 2012, or Revision 1 dated 18 October 2012.

Eurocopter AS350 SB No. 01.00.66 original issue dated 30 January 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.