EASA AD No : 2011-0127 

EASA Form 110 Page 1/4 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2011-0127 

Date: 01 July 2011 

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) : 

AS 365, EC 155, SA 365 and SA 366 

helicopters 

TCDS Number: France No. 159 

Foreign AD: Not applicable 

Supersedure: This AD supersedes DGAC France AD F-2008-004 dated 04 June 2008. 

ATA 63 Main Rotor Drive - Main Gearbox Casing – Inspection / Repair 

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

Applicability: EC 155 B, EC 155 B1, SA 365 N, SA 365 N1, AS 365 N2, AS 365 N3, SA 

366 G1, SA 365 C, SA 365 C1, SA 365 C2 and SA 365 C3 helicopters, all 

serial numbers, if equipped with Main Gearboxes (MGB), as defined in table 

1 hereunder: 

 Table 1 

MGB, all part numbers (P/N), delivered before 5 December 2007 

(inclusive), or 

MGB, all P/N, installed on helicopters delivered before 5 December 

2007 (inclusive); and 

MGB, all P/N, overhauled or repaired before 30 September 2008 

(inclusive). 

2 

Reason: In 2008, two reports were received of atmospheric corrosion on the MGB 

casing lower area of two helicopters, between the two servo-control 

anchoring fitting attachment ribs. 

The investigation showed that initiation of corrosion in this area is due to a 

confined area under the anchoring fittings, associated with PR sealing 

compound on the lower part of the fitting/casing attachment. 

This PR sealing compound may have been applied on some helicopters due 
EASA AD No : 2011-0127 

EASA Form 110 Page 2/4 

to a misinterpretation of the EUROCOPTER documentation during 

installation. 

This condition, if not detected and corrected, could lead to crack initiation and 

crack growth in the affected area of the casing which could cause this area to 

fail and consequent loss of control of the helicopter. 

This unsafe condition, which is unrelated to design approval, was addressed 

in June 2008 by DGAC France AD F-2008-004. 

Later, in July 2008, EASA issued the EASA Airworthiness Directive Policy, 

(referenced C.Y001-01) which allowed the agency to issue Airworthiness 

Directives to address non-conformities of aircraft with the EASA approved 

design, due to manufacturing or maintenance deficiencies. 

For the reasons described above and in the frame of an EASA Airworthiness 

Directive Policy catch-up process for this type of Airworthiness Directives, this 

EASA AD supersedes DGAC France AD F-2008-004 retaining all its 

requirements although it does not introduce any new requirement. 

Effective Date: 15 July 2011 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) Within 15 Flight Hours (FH) after 14 May 2008 [the effective date of the 

French superseded DGAC AD F-2008-004], inspect all the lower parts of 

the MGB servo-control anchoring fittings to detect the presence of PR 

sealing compound in accordance with the instructions of paragraph 

2.B.2. of EUROCOPTER EC 155 Alert Service Bulletin (ASB) No. 

63A011 or AS 365 ASB No. 63.00.17 or SA 360/365 ASB No. 65.47, or 

SA 366 ASB No. 65.03, as applicable to helicopter type. 

(2) If, during the inspection required by paragraph (1) of this AD, PR sealing 

compound is found on any lower part of the MGB servo-control 

anchoring fittings, before next flight, inspect the affected area for 

corrosion in accordance with the instructions of paragraph 2.B.3. of 

EUROCOPTER EC155 ASB No. 63A011 or AS365 ASB No. 63.00.17 or 

EUROCOPTER SA360/365 ASB No. 65.47, EUROCOPTER SA366 ASB 

No. 65.03, as applicable to helicopter type. 

(3) If, during the inspection required by paragraph (2) of this AD, corrosion is 

found, within the compliance time indicated in Table 1 in Appendix 1 of 

this AD, as applicable, accomplish corrective actions in accordance with 

the instructions of paragraph 2.B.3. EUROCOPTER EC155 ASB No. 

63A011 or AS365 ASB No. 63.00.17 or EUROCOPTER SA360/365 ASB 

No. 65.47, EUROCOPTER SA366 ASB No. 65.03, as applicable to 

helicopter type, and, depending on findings, accomplish a repair in 

accordance with EUROCOPTER Repair Sheet No. 365-63-36-08. 

(4) After 14 May 2008 [the effective date of the French superseded DGAC 

AD F-2008-004], do not install MGB listed in Table 1 in Appendix 1 of 

this AD on a helicopter, unless in compliance with the inspections and 

corrective actions, if any, of paragraphs (1), (2) and (3) of this AD. 

Ref. Publications: EUROCOPTER EC155 ASB No. 63A011 dated 7 May 2008. 

EUROCOPTER AS365 ASB No. 63.00.17 dated 7 May 2008. 

EUROCOPTER SA360/365 ASB No. 65.47 dated 5 May 2008. 

EUROCOPTER SA366 ASB No. 65.03 dated 7 May 2008. 

EUROCOPTER Repair Sheet No. 365-63-36-08 dated 4 April 2008. 

The use of later approved revisions of these documents is acceptable for 

compliance with the requirements of this AD. 
EASA AD No : 2011-0127 

EASA Form 110 Page 3/4 

Remarks : 1. If requested and appropriately substantiated, EASA can approve 

Alternative Methods of Compliance for this AD. 

2. This AD was posted on 05 May 2011 as PAD 11-045 for consultation 

until 02 June 2011. No comments were received during the consultation. 

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 (0) 4 42 85 97 97, Fax +33 (0) 4 42 85 99 66. 

E-mail: Directive.technical-support@eurocopter.com. 
EASA AD No : 2011-0127 

EASA Form 110 Page 4/4 

APPENDIX 1

Table 1 

Helicopter operating 

conditions: 

MGB operating 

time accumulated 

since new or since 

last complete 

overhaul: 

Compliance time, in accumulated MGB 

operating time : 

Less than 30 

months. 

33 months. 

Between 30 and 33 

months. 

33 months, or within 3 months after 14 May 2008 

[the effective date of the French superseded 

DGAC AD F-2008-004], without exceeding 55 

FH after 14 May 2008 [the effective date of the 

French superseded DGAC AD F-2008-004]. 

Helicopters that have been 

operated in one of the 

following conditions: 

- Helicopters based 

onboard a ship and 

operated off-shore, and/or 

- Helicopters operated less 

than 1 kilometre from the 

coast, and/or 

- Helicopters operated at 

low altitude (less than 

1 000 feet) over the sea. 

More than 33 

months. 

Within 3 months after 14 May 2008 [the effective 

date of the French superseded DGAC AD 

F-2008-004], without exceeding 55 FH after 14 

May 2008 [the effective date of the French 

superseded DGAC AD F-2008-004]. 

Less than 54 

months. 

60 months. 

Between 54 and 60 

months. 

60 months, or within 6 months after 14 May 2008 

[the effective date of the French superseded 

DGAC AD F-2008-004], without exceeding 110 

FH after 14 May 2008 [the effective date of the 

French superseded DGAC AD F-2008-004]. 

All other helicopters 

More than 60 

months. 

Within 6 months after 14 May 2008 [the effective 

date of the French superseded DGAC AD 

F-2008-004], without exceeding 110 FH after 14 

May 2008 [the effective date of the French 

superseded DGAC AD F-2008-004].