EASA AD No : 2011-0091 

EASA Form 110 Page 1/3 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2011-0091 

Date: 18 May 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) : 

BO105 helicopters 

TCDS Number : EASA.R.011 

Foreign AD : Not applicable 

Supersedure : This AD supersedes EASA AD 2010-0223 dated 26 October 2010. 

ATA 63 Main Rotor Drive – Main Gearbox – Inspection 

Manufacturer(s): Eurocopter Deutschland GmbH (ECD), Eurocopter Hubschrauber GmbH, 

Messerschmitt-Bölkow-Blohm GmbH 

Applicability: BO105 A, BO105 C, BO105 D and BO105 S helicopters, all variants, all serial 

numbers. 

Reason: In 2010, an accident occurred with a BO105 helicopter and the initial findings 

indicated that the event was linked with a deterioration of the Main Gearbox 

(MGB), due to a contaminated oil supply. 

This condition, if not detected and corrected, could lead to MGB failure and 

consequent loss of control of the helicopter. 

ECD developed measures to address and correct this unsafe condition and 

published these instructions in Alert Service Bulletin (ASB) BO105-10-125. 

EASA issued AD 2010-0223 to require a one-time inspection of the MGB 

magnetic plug / chip detector and of the MGB oil filter and, depending on 

findings, corrective action(s). That AD also required the implementation of new 

corrective action criteria for later (scheduled and unscheduled) MGB 

inspections, to be applied each time there is a particle identification. 

Since that AD was issued, it has been determined that repetitive inspections 

of the magnetic plug and oil filter at reduced intervals are necessary to ensure 

that any discrepancy is detected and corrected, and ASB BO105-10-125 has 

been revised accordingly. 

For the reasons described above, this AD retains the initial requirements of 

AD 2010-0223, which is superseded, and requires the implementation of 

repetitive inspections of the magnetic plug and oil filter and corrective actions, 

depending on findings. 
EASA AD No : 2011-0091 

EASA Form 110 Page 2/3 

Effective Date: 01 June 2011 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

Re-statement of requirements of AD 2010-0223: 

(1) Within the next 100 flight hours (FH) or 3 months, or at the next 

scheduled MGB magnetic plug / chip detector inspection, whichever 

occurs first after 09 November 2010 [the effective date of AD 2010-0223], 

inspect the MGB magnetic plug / chip detector and MGB oil filter for 

contamination in accordance with the instructions of ECD Alert Service 

Bulletin (ASB) BO105-10-125 and the BO105 Maintenance Manual (MM). 

(2) Thereafter, at each scheduled or unscheduled MGB magnetic plug / chip 

detector inspection, apply the instructions of Table 11-2, as provided on 

pages 4 and 5 of ECD ASB BO105-10-125. 

New requirements of this AD: 

(3) Within 10 FH after the latest check as required by EASA AD 2010-0223, 

now paragraphs (1) or (2) of this AD, as applicable, and thereafter at 

intervals not to exceed 10 FH, inspect the MGB magnetic plugs for chips, 

in accordance with the instructions of ECD ASB BO105-10-125 Revision 

1 (R1) and the BO105 MM. 

(4) Within 100 FH after the latest check as required by EASA AD 2010-0223, 

now paragraphs (1) or (2) of this AD, as applicable, and thereafter at 

intervals not to exceed 100 FH, inspect MANN oil filter Part Number (P/N) 

6140063321 for particles, in accordance with the instructions of ECD ASB 

BO105-10-125 R1 and the BO105 MM. 

(5) Accomplishment of the initial inspections on a helicopter, as required by 

paragraphs (3) and (4) of this AD respectively, constitutes terminating 

action for the repetitive inspections required by paragraph (2) of this AD. 

(6) If contamination is found during any inspection as required by paragraphs 

(1), (2), (3) or (4) of this AD, before next flight, except where ECD ASB 

BO105-10-125 R1 (page 4, table 11-2) defines different compliance 

times, accomplish the corrective actions in accordance with the 

instructions of ECD ASB BO105-10-125 R1 and the BO105 MM. 

(7) Compliance with the requirements of paragraphs (3) and (4) of this AD 

can be demonstrated by: 

(7.1) Revising as follows the approved aircraft maintenance programme 

on the basis of which the Operator or the Owner ensures the 

continuing airworthiness of each operated helicopter: 

 Incorporate the repetitive inspections of paragraphs (3) and (4) of 

this AD, as well as the revised Table 11-2 (pages 4 and 5 of ASB 

BO105-10-125 R1) and picture 11-14 (page 6 of ASB BO105-10-

125 R1) instructions. 

 and 

(7.2) Complying with the approved aircraft maintenance programme 

described in paragraph (7.1) of this AD. 

Ref. Publications: Eurocopter Deutschland ASB BO105-10-125 dated 02 September 2010, 

Revision 1 dated 04 April 2011. 

The use of later approved revisions of this document is acceptable for 

compliance with the requirements of this AD. 

BO105 Maintenance Manual, Chapter 11, Sections 11-12 through 11-19, 

including revised Table 11-2 (pages 4 and 5 of ASB BO105-10-125 R1) and 

picture 11-14 (page 6 of ASB BO105-10-125 R1). 
EASA AD No : 2011-0091 

EASA Form 110 Page 3/3 

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 Deutschland GmbH, 

Industriestrasse 4, 86607 Donauwörth, 

Federal Republic of Germany. 

Telephone: + 49 (0) 151 14 22 89 76, Facsimile: + 49 (0) 906 71-4111.