EASA AD No : 2011-0149R1

EASA Form 110 Page 1/2 

## EASA AIRWORTHINESS DIRECTIVE

AD No.: 2011-0149R1

Date: 23 September 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 opera te an aircraft to which an AD applies, except in accordance with t he requirements of that AD, unless otherwise specified by the Ag ency [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) exemptio n]. 

### Type Approval Holder’s Name : Eurocopter Deutschland GmbH Type/Model designation(s) : MBB-BK117 C-2 helicopters

TCDS Number : EASA.R.010

Foreign AD : not applicable

Revision: This AD revises EASA AD 2011-0149 dat ed 05 August 2011.



### ATA 24 Electrical Power – Generator Control Unit – Identification / Replacement

Manufacturer(s): Eurocopter Deutschland GmbH (ECD), American Eurocopter LLC

Applicability: MBB-BK117 C-2 helicopters, all serial numbers.
Reason: During an acceptance test procedure of a generator control unit (GCU), a short circuit occurred within the unit. The results of the subsequent investi gation determined that a manufacturing discrepancy was the cause of this inte rnal short circuit. All Part Number (P/N) P/N 51530-021EI “no MOD”, “MOD A” and “MOD B” GCU’s are potentially affected by this discrepancy. This condition, if not corrected, can lead to the loss of electrical generating power, possibly resulting in loss of rele vant systems that are necessary for a safe continuation of the flight. To address this potential unsafe cond ition, EASA issued AD 2011-0149 to require the identification of each a ffected GCU and replacement with a serviceable unit. Since that AD was issued, ECD has de monstrated that, for helicopters that have already been modified in accordan ce with ECD Alert Service Bulletin (ASB) MBB BK117 C-2-24A-008 Revision 1, as required by § (3) of EASA AD 2011-0162, the risk of losing electrical generating power as addressed by this AD is much lower. For the reasons described above, this AD is revised, allowing an extended compliance time for the replacement of the affected GCU for helicopters that have already been modified in acco rdance with ECD ASB MBB BK117 C-2- 24A-008 Revision 1.EASA AD No : 2011-0149R1

EASA Form 110 Page 2/2 Effective Date: Revision 1: 30 September 2011 Original issue: 19 August 2011
Required Action(s) and Compliance Time(s): Required as indicated, unless accomplished previously: (1) For helicopters that have not yet been modified in accordance with ECD ASB MBB BK117 C-2-24A-008 Revision 1, within 300 flight hours (FH) or 6 months, whichever occurs firs t after 19 August 2011 [the effective date of the original issue of this AD], accomplish the following actions in accordance with the instructio ns of ECD ASB MBB-BK117 C-2-24A010: (1.1) Identify the P/N and modification status of each GCU installed on the helicopter, and (1.2) If a GCU, identified as required by paragraph (1.1) of this AD, is listed in Table 1 of this AD, repl ace that GCU with a serviceable unit.
Table 1 – Affected GCU

Part Number Mod. Status
“no MOD”
“MOD A” P/N 51530-021EI
“MOD B”

(2) From 19 August 2011 [the effective date of the original issue of this AD], do not install on any helicopter a GCU which is listed in Table 1 of this AD. (3) For helicopters that have already been modified in accordance with ECD ASB MBB BK117 C-2-24A-008 Revision 1, accomplish the actions as specified in paragraphs (1.1) and (1.2) of this AD within 1 500 FH or 16 calendar months, whichever occurs first after 19 August 2011 [the effective date of the original issue of this AD], in accordance with the instructions of ECD ASB MBB-BK117 C-2-24A-010.

Ref. Publications: ECD ASB MBB BK117 C-2-24A -008 Revision 1 dated 29 August 2011. ECD ASB MBB-BK117 C-2-24A-010 Revision 1 dated 01 July 2011, and Revision 2 dated 14 September 2011. 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 06 June 2011 as PAD 11- 058 for consultation until 04 July 2011 and republished on 12 July 2011 as PAD 11-058R1 for extended consultation until 26 July 2011. No comments were received during the consultation period. 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 tec hnical 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.