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 – Yaw-Actuator – Inspect Yaw-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 Yaw-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 Yaw-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

3X4

4

4

1

4

1

2

4X4

3X4 5

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:___________________

Helicopter Yaw-Actuator

S/N:

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

Remarks: