# ALERT SERVICE BULLETIN **MBB BK117 C-2**

**MBB BK117 C-2-22A-009** PAGE 1 of 5 2008-05-13 REVISION 01, 2009-08-03 

## Auto Flight System – Y **aw-Actuator – Inspect Y**  **aw-SEMA/YawSEMA control rod for correct attachment hardware**  **1. Planning Information A. Effectivity**  (1) Helicopters affected: All MBB BK117 C-2. (2) Components affected: 

### YawSEMA control rod B673M4003102 (3) Spare Parts affected: 

### YawSEMA control rod B673M4003102 **B. Concurrent Requirements** Not applicable. **C. Reason** During the installation work on a helicopter, it has been detected that it was not possible to establish attachment hardware on a threaded blind borehole between SEMA (Smart Electro Mechanical Actuator) and the **YawSEMA control rod** without play. The reason for this loose attachment hardware was an unfavourable adding of the tolerances of the attachment hardware elements. The result of this was that the screw first pushed against the bottom of the threaded blind borehole on the SEMA so that no clamping effect on the screw head could be achieved. Therefore, this Alert Service Bulletin prescribes the check of the Yaw-SEMA for attachment hardware that is connected to the **YawSEMA control rod** without play and, if necessary, the establishment of a connection that is free from play. **D. Description** Check attachment hardware between Yaw-SEMA and **YawSEMA control rod** . If necessary, loosen attachment hardware and establish attachment hardware that is free from play. **E. Compliance** (1) The check and the possibly required correction of the attachment hardware connection i.a.w. Section 3.B must be accomplished within the next 50 fh after receipt of this Alert Service Bulletin. (2) If Yaw-SEMA and **YawSEMA control rod** must be screwed together in future, it must be ensured that the attachment hardware connections must be established without play i.a.w. Section 3.B of this Alert Service Bulletin. **F. Approval** The technical content of this document is approved under the authority of DOA No. EASA.21J.034

This document is available on the internet: www .eurocopter.com/techpub

# ALERT SERVICE BULLETIN **MBB BK117 C-2**

**MBB BK117 C-2-22A-009** PAGE 2 of 5 REVISION 01, 2009-08-03 2008-05-13 **G. Manpower** Approx. 1.5 man–hours for check of attachment hardware. **H. Weight and Balance** Not applicable. **I. Electrical Load Data** Not applicable. **J. Software Accomplishment Summary** Not applicable. **K. References** AMM MBB BK117 C-2. **L. Other Publications affected** The changes to AMM MBB BK117 C-2 and IPC MBB BK117 C-2 will be incorporated with one of the next revisions. **M. Interchangeability of Parts** Not applicable.



### 2. Material Information **A. Material – Price and Availability** – The possible necessary washers EN2139-05016 and screws ISO4762-M5X16-A2-70 must be seperately ordered by ECD. – Consumable material PU-laquer (CM 478), hardener (CM 479), thinner (CM 480) to be ordered as needed from the Interturbine company. CM item number i.a.w. list of consumable materials in the AMM. **B. Support Information** Not applicable. **C. Material Necessary for Each Helicopter** Not applicable. **D. Material Necessary for Each Spare** Not applicable.

# ALERT SERVICE BULLETIN **MBB BK117 C-2**

**MBB BK117 C-2-22A-009** PAGE 3 of 5 2008-05-13 REVISION 01, 2009-08-03 **E. Reidentified Parts** Not applicable. **F. Special Tooling** Not applicable.


### 3. Accomplishment Instructions A. Preliminary work: (1) Remove vertical fin fairing i.a.w. AMM, 53-52-00, 4-1. B. Yaw actuator: (1) Check attachment hardware between Y aw-SEMA (1, Figure 1) and **YawSEMA control rod**  (2): (a) Check manually or with a suitable aid, whether the washers (4, , Detail A, Figure 1) can be moved. 1 If both washers (4, ) cannot be moved, install vertical fin fairing i.a.w. AMM, 53-52-00, 4-1. 2 If one or both washers (4, ) can be moved, remove **all four** screws (3) and discard. Remove grounding strip (6). Store all four washers (4) for reuse and proceed as follows:
a Connect Y aw-SEMA (1, Detail B, Figure 1) and **YawSEMA control rod** (2) with four **new** screws (3), the old four washers (4) and **two** additional washers (5, ). Install grounding strip (6). Torque–tighten screws (3) to 5–6 Nm and apply PU-laquer (CM 478, CM 479, CM 480) onto attachment hardware. C. Conclusive work: (1) Install vertical fin fairing i.a.w. AMM, 53-52-00, 4-1 (2) Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of the helicopter. (3) If loose washers are detected, copy reply form sheet on page 5, fill out and send to ECD customer support.


### 4. Appendix Not applicable.

# ALERT SERVICE BULLETIN **MBB BK117 C-2**

**MBB BK117 C-2-22A-009** PAGE 4 of 5 REVISION 01, 2009-08-03 2008-05-13 Yaw-Actuator Figure 1 1 Yaw-SEMA 2 YawSEMA control rod **B673M4003102** 3 Screw ISO4762-M5X16-A2-70 4 Washer LN29932-05 5 Washer EN2139-05016 6 Grounding strip View: (against flight direction)



### Detail 

## A

Detail 

## B (with additional washers) 

## A

1 2

5–6 Nm 2 3 X4 4

4

1

4 1 2

4 X4 5 3 X4 5 6

Check, whether the two washers can be moved. If necessary, install one addtional washer (5) on each of these two screws. If removed, re-attach grounding strip and apply PU-laquer (CM 478, CM 479, CM 480) onto attachment hardware.

# ALERT SERVICE BULLETIN **MBB BK117 C-2**

**MBB BK117 C-2-22A-009** PAGE 5 of 5 2008-05-13 REVISION 01, 2009-08-03 

# Telefax

To Eurocopter Deutschland GmbH Customer Support FAX 0049 906 714111 Address of operator: **Reply form sheet for ASB MBB BK117 C-2-22A-009 ”Check Yaw-SEMA/YawSEMA control rod for correct attachment”**  Please completely fill out reply form sheet and send to the given FAX No.

Date:__________ Signature:___________________ Yaw-Actuator Helicopter S/N:

**Please copy page! Original page remains in Alert Service Bulletin!**

Remarks: