EASA AD No.: 2010-0100R1 

EASA Form 110 Page 1/3 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2010-0100R1 

Corrected: 11 August 2010 

Date: 04 August 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) : 

SA 365 and AS 365 helicopters 

TCDS Number : France No.159 

Foreign AD : Not applicable 

Revision: This AD revises EASA Emergency AD 2010-0100-E dated 26 May 2010, which 

superseded EASA AD 2009-0241-E dated 05 November 2009 and its correction 

dated 10 December 2009. 

ATA 34 Navigation - Vertical Gyro Unit Data Output - Operational Limitation 

/ Operational Procedure / Reinforcement 

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

Applicability: SA 365 N1, AS 365 N2 and AS 365 N3 helicopters, all serial numbers except 

6698, 6701, 6723, 6737 and 6741, delivered before 01 May 2010, flying in IMC 

(Instrumental Meteorological Conditions), IFR (Instrument Flight Rules) or Night 

VFR (Visual Flight Rules) conditions, if equipped with the vertical gyro units 

GV76-1 installed on the rear left hand (LH) or rear right hand (RH) rack, on 

which modification 365P081895 (reinforcement of rack for vertical gyro unit 

GV76-1 in the rear compartment) has not been incorporated. 

Helicopters equipped with electromechanical horizons (instead of attitude 

display screens) are not affected by the requirements of this AD. 

Reasons A slow drift in the roll axis on the pilot’s and co-pilot’s horizon of the flight control 

displays occurred simultaneously during flight on several helicopters equipped 

with the GV76-1 vertical gyro unit installation in cargo compartment. 

Investigation has shown that these drifts were caused by a fault in the vertical 

gyros unit installation in the rear cargo. 

In certain configurations, the GV76-1 vertical gyro unit installation has a natural 

mode close to the main rotor’s harmonic frequency which generates rather 

significant vibratory levels on the GV76-1unit by amplifying the intrinsic vibration 

of the aircraft. The faults are caused by these vibratory levels. 
EASA AD No.: 2010-0100R1 

EASA Form 110 Page 2/3 

In fact the load on the upper shelf has no effect on this mode. The critical mode 

is essentially due to bending on the horizontal cross-members which support the 

GV76-1 shelf. 

Pending the availability of a corrective action aimed at precluding any risk of drift 

on the pilots’ horizons occurring at the same time and in the same direction, 

EASA AD 2008-0195-E mandated an operational limitation and an operational 

procedure for all flights in IMC (IFR) or night VFR. 

EASA 2009-0241-E which superseded EASA AD-2008-0195-E, was issued in 

order to extend the applicability to SA 365 N1 and AS 365 N2 helicopters and to 

any SA 365 N1, AS 365 N2 and AS 365 N3 helicopter equipped with vertical 

gyro units GV76-1 installed on the rear RH rack. 

For the reasons described above, EASA Emergency AD 2010-0100-E was 

issued, retaining the requirements of EASA 2009-0241-E, which was 

superseded, requiring the embodiment of the modification 365P081895 which 

require to reinforce the GV76-1 vertical gyro unit upper shelf by adding two 

attachment points between the cargo floor and the horizontal cross-members of 

the shelf which supports the GV76-1 units. Embodiment of the modification 

365P081895 constitutes a terminating action for the operational limitation 

imposed by this AD. 

This AD has been revised to exclude some individual helicopters (which have a 

different configuration) from the Applicability, as well as all helicopters that have 

electromechanical horizons installed instead of attitude display screens. 

This AD has been republished to correct a typographical error; this AD should 

be referencing Revision 1 of Eurocopter AS365 ASB 34.00.31, not R2. 

Effective Date: 

Revision 1: 18 August 2010 

Original Issue: 28 May 2010 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) From 28 May 2010 [the effective date of the original issue of this AD], if one 

of the following equipments: the autopilot channels, the flight coupler and 

the stand-by horizon is/are not fully operative, operating the helicopter in 

IMC or Night VFR condition is prohibited. 

(2) During each flight after 28 May 2010 [the effective date of the original issue 

of this AD], if the autopilot channels, the flight coupler and the stand-by 

horizon are fully operative in both the single-pilot and the two-pilot 

configuration, the operational procedure described in paragraph 2.B. of 

Eurocopter Alert Service Bulletin (ASB) No. 01.00.61 must be 

accomplished at intervals not exceeding 5 flying minutes during flight 

phases in IMC conditions, IFR conditions or Night VFR without visible 

horizon conditions. 

(3) Compliance with this AD may be recorded by inserting a copy of this AD 

into section 4-8 “special operating procedure” of the Rotorcraft Flight 

Manual (RFM). 

(4) Within 110 flight hours after 28 May 2010 [the effective date of the original 

issue of this AD], but not later than 31 December 2010, reinforce the GV76-

1 vertical gyro unit upper shelf in accordance with paragraph 2.B of the 

EASB AS 365 No. 34.00.31. Modification of a helicopter as required by 

paragraph (4) of this AD constitutes terminating action for the limitation 

imposed by paragraph (1) of this AD and the repetitive check requirements 

of paragraph (2) of this AD. 
EASA AD No.: 2010-0100R1 

EASA Form 110 Page 3/3 

Ref. Publications: Eurocopter AS365 ASB No.01.00.61 Revision 3 dated 28 July 2010. 

Eurocopter AS365 ASB No.34.00.31 Revision 1 dated 28 July 2010. 

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 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 & 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.