EASA AD No.: 2008-0007R3 

EASA Form 110 Page 1/4 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2008-0007R3 

Date: 12 May 2010 

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 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 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]. 

Type Approval Holder’s Name : 

EUROCOPTER 

Type/Model designation(s) : 

EC 225 LP helicopters 

TCDS Number : EASA.R.002 

Foreign AD : Not applicable 

Revision : This AD revises EASA AD 2008-0007R2 dated 17 December 2008 

ATA 04, 63 Limitations – 14Hz Vibrations at Low Density Altitude 

Manufacturer(s): EUROCOPTER 

Applicability: EC 225 LP helicopters, all serial numbers, if: 

- not equipped of all three modifications MOD 0726582, MOD 0726477 and 

MOD 0726583, or, 

- if not equipped of MOD 0726592, or, 

- if equipped with all three modifications MOD 0726606, MOD 0726610, MOD 

0726611 and missing accomplishment of MOD 0726632. 

Note 1:

Above referenced MODs are modifications accomplished during production. In 

order to determine in-service accomplishment Service Bulletins of these 

modifications, refer to EUROCOPTER EC 225 Alert Service Bulletin No. 

04A001 revision 3.

Reason: Due to the main rotor control linkage design, there is a coupling between the 

Main Gearbox (MGB) motion and the main servo-control inputs. In certain 

flight conditions with increased air density, this generates spurious 14Hz 

control inputs in the main rotor which, in return, transfers dynamic loads to the 

structure, with feedback on the MGB motion, inducing a continuous vibration 

phenomenon. Flight tests have shown that there is a density altitude (Hσ) limit 

below which the occurrence of the vibration phenomenon is significantly 

increased or even diverges, which could lead to the loss of control of the 

helicopter. Pending availability of the Rotorcraft Flight Manuals’ (RFM) 

revisions, EASA issued Emergency AD 2006-0056-E to require limiting the 

flight envelope, mitigating the risk of recurrence of the vibration phenomenon. 
EASA AD No.: 2008-0007R3 

EASA Form 110 Page 2/4 

Subsequently, EUROCOPTER developed modification (MOD) 0726532 

relating to VMS software, MOD 0726477 relating to servo-controls with 

attenuated dynamic response and MOD 0726536 relating to FADEC software. 

Embodiment of these three modifications aimed to relieve the affected 

helicopters of the required flight envelope limitations. AD 2006-0056 Revision 

1 was therefore issued to update the “Applicability” paragraph with information 

that when MOD 0726532, MOD 0726477 and MOD 0726536 were all installed 

together, this was considered as an optional terminating action, allowing the 

flight envelope limitations to be removed. In addition, AD 2006-0056 R1 took 

into account the availability of RFM revisions containing the required altitude 

limitations in order to relieve the need of maintaining a copy of this AD in the 

RFM. 

Later on, flight test campaign and analysis showed that even with the 3 

referenced MODs installed, the spurious 14Hz vibration phenomenon may not 

be totally precluded from the re-established flight envelope for certain flight 

conditions. Therefore, VMS and FADEC software versions have been 

upgraded, redefining the optional terminating action so that respectively, MOD 

0726532 has been replaced with MOD 0726582 (VMS software version 

V11.01) and MOD 0726536 has been replaced with MOD 0726583 (FADEC 

software version V2.4.5) and the RFM revisions mentioned before have been 

amended accordingly. 

For the reasons described above, AD 2008-0007 was issued to retain the 

requirements of AD 2006-0056 R1 which was superseded, imposing limitations 

on the flight envelope as originally specified, and redefining the optional 

terminating action that allowed operators to become relieved from the limitation 

to operate below -2 000 feet Hσ , by accomplishing MOD 0726582, MOD 

0726477 and MOD 0726583 (modifications which permit to operate up to the 

certification Hσ of -3.500 feet), and by requiring the implementation of updated 

versions of the RFM Conditional Revisions RCe relevant to these 3 

modifications. 

Revision 1 of this AD was issued to take into account the certification of a flight 

envelope expansion that occurred in the meantime and which has resulted in a 

new definition of the limitations imposed by paragraph (1) of this AD. In addition, 

it aimed to correct incomplete references to RFM Conditional Revisions RCe in 

paragraph (3) of this AD and to add paragraph (4) to clarify the optional 

terminating action for the requirements of this AD.

Revision 2 of this AD was issued to correct the text of the limitation (density 

altitude instead of pressure altitude) in paragraph (1) so that it remained 

consistent with the title of the AD and with RFM revisions contents. 

Thereafter, EUROCOPTER has on one hand designed MOD 0726592 (new 

MAKILA 2A1 engines, including MOD 0726583 and requiring MOD 0726582 

and MOD 0726477) and on the other hand continued its development work for 

expansion of the flight envelope towards a lower Hσ. The last led to the 

approval of several new modifications allowing the expansion the flight 

envelope up to - 6,000 feet Hσ with no risk that the vibration phenomenon 

occurs. 

The - 6,000 feet Hσ is possible when the helicopter is modified with the MOD 

0726632 (-6,000 feet Hσ flight envelope) which encompasses a batch of 

associated modifications: previous MOD 0726477 (attenuated servo-controls) 

and new MOD 0726610 (FADEC software update, version V12), MOD 

0726611(VMS software update, version V2.4.6), MOD 0726606 (Autopilot 

software version S9.51) and also complementary MOD 0726631 (relevant 

wiring provisions). 

Revision 3 of this AD is now issued : 

- to take into account the approval of these new modifications (that are 

an alternative optional terminating actions for the requirements of this 

AD), 

- to inform which helicopters remain subject to the limit of operation at 

-2,000 feet Hσ, and, 
EASA AD No.: 2008-0007R3 

EASA Form 110 Page 3/4 

- to require the RFM update with appropriate RFM revisions that results 

of latest modifications approval. 

Effective Date: 26 May 2010. 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously:

(1) On each flight as from March 01, 2006 [the effective date of Emergency 

AD 2006-0056-E], comply with the flight envelope limitation specified 

below: 

Operation below -2 000 feet (-610 m) density altitude (Hσ) is 

PROHIBITED. 

(2) Within 30 days after the effective date of this AD, ensure that the 

Rotorcraft Flight Manual is updated with the following revisions, as 

applicable: 

- For standard EC 225 LP helicopters (equipped with air intakes fitted 

with screens): Normal Revision RN11 (10-04) in combination with 

Conditional Revision RCe (10-04), 

 or 

- For EC 225 LP helicopters equipped with MPAI (multi purpose air 

intakes): Normal Revision RN21 (10-05) in combination with 

Conditional Revision RCe (10-04). 

(3) At the operator’s discretion, accomplishment on any helicopter of either all 

three modifications MOD 0726582, MOD 0726477, MOD 0726583, or the 

MOD 0726592, or all three modifications MOD 0726606, MOD 0726610, 

MOD 0726611 in conjunction of MOD 0726632, the limitation and RFM 

Conditional revisions imposed by paragraphs (1) and (2) of this AD are no 

longer required for that helicopter. 

Note 2: 

MOD 0726592 (MAKILA 2A1 engines) includes MOD 0726583 (FADEC 

software V11.01) and requires also MOD 0726582 (VMS software 

V2.4.5) and MOD 0726477 (servo-controls with attenuated dynamic 

response). 

Note 3:

MOD 0726610 (FADEC software update, version V12) and MOD 

0726611 (VMS software update, version V2.4.6) replace MOD 0726583 

and MOD 0726582 respectively. The two new modifications MOD 

0726610, MOD 0726611 must always be accomplished together and 

also jointly with MOD 0726606 (Autopilot software version S9.51). 

Note 4:

MOD 0726632 (Hσ = -6,000 feet flight envelope) requires all three 

modifications MOD 0726610, MOD 0726611, MOD 0726606 have been 

accomplished and imposes also the MOD 0726477 and complementary 

MOD 0726631 (wiring provisions for low Hσ flight envelope). 

Ref. Publications: EUROCOPTER EC 225 Alert Service Bulletin No. 04A001 revision 3. 

Normal Revision RN11 (10-04) / Conditional Revision RCe (10-04). 
EASA AD No.: 2008-0007R3 

EASA Form 110 Page 4/4 

Normal Revision RN21 (10-05) / Conditional Revision RCe (10-04). 

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. The original issue of this AD was posted on 13 December 2007 as 

PAD 07-223 for consultation until 27 December 2007. No comments were 

received during the consultation period. 

3. Enquiries regarding this AD should be referred to the Airworthiness 

Directives, Safety Management & Research Section, Certification 

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 (0) 4 42 85 97 97; Fax: 33 (0) 4 42 85 99 66. 

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