EASA AD No.: 2009-0106R1 

EASA Form 110 Page 1/3 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2009-0106R1 

Date: 03 November 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 Deutschland GmbH

Type/Model designation(s) : 

EC135 and EC635 helicopters 

TCDS Number : EASA R.009 

Foreign AD : Not applicable 

Revision: This AD revises EASA Emergency AD 2009-0106-E dated 30 April 2009, which 

superseded EASA Emergency AD 2008-0116-E dated 17 June 2008. 

ATA 63 Main Rotor Drive – Main Gearbox (MGB) Oil Sampling & 

Analysis Program – Amendment 

Manufacturer(s): Eurocopter Deutschland GmbH, Eurocopter ESPANA S.A. 

Applicability: EC135 helicopters, model P1(CDS), P1(CPDS), P2(CPDS), P2+, T1(CDS), 

T1(CPDS), T2(CPDS) and T2+, all serial numbers, and 

EC635 helicopters, model T1(CPDS), P2+ and T2+, all serial numbers, if a 

MGB Part Number (P/N) 4649 010 003, P/N 4649 010 005, P/N 4649 010 

006, P/N 4649 010 006X, P/N 4649 010 008, P/N 4649 010 008X, 

P/N 4649 001 007, P/N 4649 010 010, or P/N 4649 010 013 is installed. 

Reason: Following several chip indications, a main gearbox was returned for repair to 

the manufacturer of the main gearbox, ZF Luftfahrttechnik (ZFL). During 

disassembly, a partial tooth rupture was detected after removal of a drive 

pinion. This tooth rupture was determined to have been caused by wear. 

To monitor the condition of the main gearbox (MGB), Eurocopter 

Deutschland (ECD) developed a program for oil samples to be taken and 

analysed at regular intervals, to ensure that wear is detected in time, prior to 

actual tooth rupture, and that appropriate corrective measures are taken 

following chip indication(s). EASA issued AD 2008-0082 (later revised) to 

require operators to implement the oil sampling and analysis program and 

take appropriate corrective actions. Following further technical analysis, the 

corrective actions were adapted and EASA issued AD 2008-0116-E, 

superseding AD 2008-0082R1 and retaining its requirements, to require a 

one-time check of chip indication records over the last 300 flight hours (FH), 

with subsequent corrective measures and implementation of the adapted 

corrective measures into the oil sampling and analysis program. After EASA 

AD 2008-0116-E was issued, it was shown that a definition of the oil change 
EASA AD No.: 2009-0106R1 

EASA Form 110 Page 2/3 

interval in case of contamination with water was necessary. 

For that reason, EASA issued Emergency AD 2009-0106-E, superseding 

EASA AD 2008-0116-E and retaining its requirements, to require an oil 

change in case of water contamination, in accordance with the instructions 

of ECD Alert Service Bulletin (ASB) EC135-63A-012 Revision 04. 

More recently, ECD published ASB EC135-63A-012 Revision 05, indicating 

that a modification to the MGB, involving a new input stage, has been 

developed, changing the P/N. The MGB modification can be introduced 

during repair and/or overhaul of the MGB. Prompted by this development, 

this AD is revised to exclude helicopters from the Applicability that have a 

modified MGB installed, and to confirm that installation on a helicopter, of a 

MGB with a P/N not listed in the Applicability of this AD, constitutes 

terminating action for the repetitive actions required by this AD for that 

helicopter. 

Effective Date: Revision 1: 10 November 2011 

Original issue: 02 May 2009 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) For EC135 and EC635 series helicopters with serial numbers (s/n) up 

to 504 inclusive that have not been modified in accordance with ECD 

Service Bulletin (SB) EC135-63-011 (retrofit to a more efficient 

lubricating oil), within the next 100 flight hours (FH) after 09 May 2008 

[the effective date of AD 2008-0082], take the first oil sample in 

accordance with the instructions of ECD ASB EC135-63A-012. 

(2) For EC135 and EC635 series helicopters with s/n up to 504 inclusive 

that have been modified in accordance with ECD SB EC135-63-011, 

within the next 100 FH after 09 May 2008 [the effective date of AD 

2008-0082], but not prior to accumulating 100 FH after accomplishment 

of SB EC135-63-011, take the first oil sample in accordance with the 

instructions of ECD ASB EC135-63A-012. 

(3) For EC135 and EC635 series helicopters with s/n 505 and up, within 

the next 100 FH, but not prior to accumulating 90 FH after the first oil 

change, whichever occurs later after 09 May 2008 [the effective date of 

AD 2008-0082] (the first oil change must be accomplished when 50 FH 

have been accumulated since new), take the first oil sample in 

accordance with the instructions of ECD ASB EC135-63A-012. 

(4) After taking the first oil sample, take further oil samples at intervals not 

to exceed 100 FH (+/- 10% tolerance) or 12 months, whichever occurs 

first, in accordance with the instructions of ECD ASB EC135-63A-012. 

(5) Before the helicopter accumulates 25 FH after taking each oil sample, 

accomplish the analysis in accordance with the instructions of ECD 

ASB EC135-63A-012 and, depending on the results, take the corrective 

measures as specified and at the time(s) as specified in ECD ASB 

EC135-63A-012 at Revision 04, or a later revision; 

(6) Oil sampling, analysis and corrective actions accomplished prior to the 

effective date of this AD, in accordance with the instructions of ECD 

ASB EC135-63A-012 at original issue or Revision 01, Revision 002 or 

Revision 03, are acceptable to comply with the initial requirements of 

this AD. After 02 May 2009 [the effective date of the original issue of 

this AD], oil sampling, analysis and corrective actions must be 

accomplished in accordance with the instructions of ECD ASB EC135-

63A-012 Revision 04, or a later revision. 
EASA AD No.: 2009-0106R1 

EASA Form 110 Page 3/3 

(7) When a MGB is installed that has accumulated 300 FH or more total 

time, or time since overhaul, or time since repair, before further flight, 

check the log card of the MGB for entries regarding chip indications 

and, depending on the results, at the time(s) specified in ECD ASB 

EC135-63A-012, accomplish the tasks and take the applicable 

corrective measures, in accordance with the instructions of ECD ASB 

EC135-63A-012. 

(8) At any time after the effective date of this AD, in case of a chip detector 

indication, at the time(s) specified in ECD ASB EC135-63A-012, 

accomplish the tasks and take the applicable corrective measures, in 

accordance with the instructions of ECD ASB EC135-63A-012. 

(9) Modification of a helicopter, by installation of a MGB with a P/N not 

listed in the Applicability of this AD, constitutes terminating action for 

the requirements of this AD for that helicopter. 

Ref. Publications: Eurocopter EC135 Alert Service Bulletin No. EC135-63A-012 Revision 04 

dated 27 April 2009 or Revision 05 dated 06 September 2011. 

The use of later approved revisions of this document 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 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 Deutschland GmbH, 

Industriestrasse 4, 86607 Donauwörth, 

Federal Republic of Germany 

Telephone: + 49 (0)151-1422 8976; Facsimile: + 49 (0)906-71 4111