EASA AD No.: 2013

- 0154

TE. CAP.00110

- 00 3 © European Aviation Safety Agency. All rights reserved. 1 / 3 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. 

## EASA AIRWORTHINESS DIRECTIVE

AD No

. : 2013 - 0154

Date: 22 July 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 E U 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 ope rate 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 DEUTSCHLAND GmbH 

### Type/Model designation(s) : MBB

- BK117 helicopters

TCDS Number: EASA.R.010

F oreign AD: Not applicable Supersedure: None



### ATA 76 Engine Controls

– N2 Control Arm
– Inspection / Modification

Manufacturer(s): Eurocopter Deutschland GmbH (formerly Messerschmitt

- Bölkow

- Blohm GmbH, Eurocopter Hubschrauber GmbH), American Eurocopter LLC Applicability: MBB

- BK117 A

- 1, A

- 3, A

- 4, B

- 1, B

- 2, C

- 1 and C

- 2 helicopters, all serial numbers.
Reason: In a recent incident on a MBB

- BK117 C

- 2 helicopter, the aircrew noticed a drop of the rotor speed / RPM within the green range, which could not be re

- adjusted back to the nominal value. An inspection of the e ngine N2 control system revealed a h eavily corroded and broken N2 control arm. T his broken control arm was responsible for the loss of the engine droop compensation. Further analysis revealed that , under unfavourable circumstances and depending on flight condition and power demand, a broken control arm can cause a significant and non

- recoverable drop in ro tor RPM. This condition, if not detected and corrected, could lead to a loss of control of the helicopter. To address this potential unsafe condition, Eurocopter (ECD) issued Alert Service Bulletin (ASB) MBB

- BK117

- 60A

- 126 for MBB

- BK117 m odel A

- 1 , A

- 3, A

- 4, B

- 1, B

- 2, and C

- 1 helicopters, and ASB MBB

- BK117 C

- 2

- 76A

- 005 for m odel C

- 2 helicopters, providing instructions for an initial inspection, followed by repetitive inspections, of the N2 control arm.
Effective Date: 05 August 2013EASA AD No.: 2013

- 0154

TE. CAP.00110

- 00 3 © European Aviation Safety Agency. All rights reserved. 2 / 3 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. Required A ction(s) and Compliance Time(s) : Required as indicated, unless accomplished previously: (1) Within the compliance time as identified in Table 1 of this AD and , thereafter, at intervals not to exceed 12 months, inspect the N2 control arm for corrosion in accord ance with the instructions of ECD ASB MBB

- BK117 C

- 2

- 76A

- 005 or ASB MBB

- BK117

- 60A

- 126, as applicable to helicopter Model

. Table 1 Date of Helicopter First Flight Compliance time M ore than 2 years before the effective date of this AD W ithin 4 weeks after the effective date of this AD

L ess than 2 years before the effective date of this AD Before reaching 2 years after the date of first flight, or w ithin 12 months after the effective date of this AD , whichever occurs first
Note: A non

- cumulative tolerance of 3 months can be applied for the initial inspection on helicopters with less than 2 years from the date of first flight and for the repetitive inspections required by paragraph ( 1 ) of this AD

. (2) If, during any inspection as required by paragraph (1) of this AD, a part shows suspected exfoliation corrosion, before next flight, replace the part with a serviceable part. (3) If, during any inspection as required by paragraph (1) of this AD, damage, corros ion and/or scratches of 0.5 mm or more are found, before next flight, replace the affected part with a serviceable part. (4) If, during any inspection as required by paragraph (1) of this AD, damage, corrosion and/or scratches of less than 0.5 mm are found, be fore next flight, accomplish corrective action in accordance with the instructions of ECD ASB MBB

- BK117 C

- 2

- 76A

- 005 or ECD ASB MBB

- BK117

- 60A

- 126 , as applicable to helicopter M odel. (5) Replacement of affected parts with serviceable parts as required by paragraph s (2) and (3) of this AD or corrective action as required by paragraph (4) of this AD do not constitute terminating action for the repetitive inspections required by paragraph (1) of this AD. (6) After the initial inspection as require d by paragraph (1) of the AD has been accomplished, compliance with the requirements of this AD can be demonstrated by (6.1) Revising, as follows, the approved Aircraft Maintenance Programme (AMP) on the basis of which the Operator or the Owner ensures the continuing airworthiness of each operated aeroplane: Incorporate the repetitive 12

- months inspection of the N2 control arm specified in the Aircraft Maintenance Manual (AMM) MBB

BK117 C

- 2 Revision 14 or AMM MBB

- BK117 A

- B Revision 43 / AMM MBB

- BK117 C

- 1 R evision 26, as applicable to helicopter Model, and (6.2) Complying with the approved AMP described in paragraph (6.1) of this AD
Ref. Public ations: ECD ASB MBB

- BK117 C

- 2

- 76A

- 005 , original issue dated 24 June 2013. ECD ASB MBB

- BK117

- 60A

- 126 , original issue dated 24 June 2013. The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD.EASA AD No.: 2013

- 0154

TE. CAP.00110

- 00 3 © European Aviation Safety Agency. All rights reserved. 3 / 3 Proprietary document. Copies are not controlled. Confirm revision status through the EASA

- Internet/Intranet. Remarks: 1. If requested and appropriately substantiated , EASA can approve Alternative Methods of Compliance for this AD. 2. Based on t he 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 A D 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, Germany Telephone: + 49 (0)151 1422 8976, Fax: + 49 (0)906 71 4111.