ALERT SERVICE BULLETIN

MBB BK117 C-2

MBB BK117 C-2-65A-003

PAGE 1 of 4

2009-05-04

Tail Rotor Drive – Tail Rotor Drive Shaft – Inspection of long tail rotor

drive shaft for correct rivets

1. Planning Information

A. Effectivity

(1) Helicopters affected: All MBB BK117 C-2.

(2) Components affected: Shaft assy B651M1002101 or

B651M1002102

(3) Spare Parts affected: Shaft assy B651M1002101 or

B651M1002102

B. Concurrent Requirements

The repair of the long tail rotor drive shaft i.a.w. AMM, 65-11-00, 8-3 is deleted and must no

longer be accomplished.

C. Reason

During a new verification of the AMM MBB BK117 C-2 it was detected that the customer has

been allowed to replace on the long tail rotor drive shaft the solid rivets with blind rivets i.a.w.

AMM, 65-11-00, 8-3. The later use of blind rivets will lead to a significant reduction of the

lifetime of the long tail rotor drive shaft. Therefore the repair of the long tail rotor drive shaft

i.a.w. AMM, 65-11-00, 8-3 is deleted and must no longer be accomplished. All delivered

helicopters are fitted with solid rivets. Therefore only long tail rotor drive shafts that have

been repaired i.a.w. AMM, 65-11-00, 8-3 will have blind rivets installed. With this Alert

Service Bulletin, the affected long tail rotor drive shafts must be inspected for correct rivets.

D. Description

Remove aft cowlings and tail boom fairings. Inspect the long tail rotor drive shaft for correct

rivets. If necessary replace shaft assy with a servicable part.

E. Compliance

(1) The inspection of the long tail rotor drive shaft for correct rivets i.a.w. Section 3.B must

be accomplished within the next 100 Fh after receipt of this Alert Service Bulletin.

(2) If the inspection of the long tail rotor drive shaft i.a.w. Section 3.B shows that no blind

rivets are installed, install tail boom fairings and aft cowlings i.a.w. Section 3.D and

confirm accomplishment of this Alert Service Bulletin i.a.w. Section 3.E. No further

measures are required.

(3) If the inspection of the long tail rotor drive shaft i.a.w. Section 3.B shows that blind rivets

are installed, replace the shaft assy with a serviceable part i.a.w. Section 3.C within the

next 100 Fh after the inspection.

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

MBB BK117 C-2

MBB BK117 C-2-65A-003

PAGE 2 of 4

2009-05-04

F. Approval

The technical content of this document is approved under the authority of

DOA No. EASA.21J.034

G. Manpower

Approx. 2 man–hours.

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 which are required as a result of this Alert Service

Bulletin will be incorporated with one of the next revisions.

M. Interchangeability of Parts

Not applicable.

2. Material Information

Not applicable.

A. Material – Price and Availability

Not applicable.

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-2-65A-003

PAGE 3 of 4

2009-05-04

E. Reidentified Parts

Not applicable.

F. Special Tooling

Not applicable.

3. Accomplishment Instructions

A. Preliminary work steps:

(1) Remove aft cowlings i.a.w. AMM, 71-11-00, 4-5.

(2) Remove tail boom fairings i.a.w. AMM, 53-51-00, 4-1.

B. Inspect long tail rotor drive shaft for correct rivets:

(1) If no blind rivets (4, Figure 1) are installed on the shaft assy (2), proceed i.a.w.

Section 3.D.

(2) If one or more blind rivets (4, Figure 1) are installed on the shaft assy (2), replace shaft

assy (2) i.a.w. Section 3.C.

C. Replace shaft assy of the long tail rotor drive shaft:

(1) Remove long tail rotor drive shaft (1, Figure 1) i.a.w. AMM, 65-11-00, 4-2.

(2) Disassemble the long tail rotor drive shaft (1) i.a.w. AMM, 65-11-00, 4-6.

(3) Assemble the long tail rotor drive shaft (1) i.a.w. AMM, 65-11-00, 4-6, using a

serviceable shaft assy (2).

(4) Install long tail rotor drive shaft (1, Figure 1) i.a.w. AMM, 65-11-00, 4-2.

D. Conclusive work:

(1) Install tail boom fairings i.a.w. AMM, 53-51-00, 4-1.

(2) Install aft cowlings i.a.w. AMM, 71-11-00, 4-5.

E. Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of

the helicopter.

4. Appendix

Not applicable.
ALERT SERVICE BULLETIN

MBB BK117 C-2

MBB BK117 C-2-65A-003

PAGE 4 of 4

2009-05-04

Long tail rotor drive Shaft

Figure 1

1 Long tail rotor drive shaft

2 Shaft assy B651M1002101 or

B651M1002102

3 Solid rivet

4 Blind rivet

Inspect if one or more blind rivets are installed.

3X30 4X30

A

Solid rivets Blind rivets

1

2

A

A Section A–A

Only one section and maximum number of rivets shown.

B

B

Solid rivets Blind rivets

Section B–B

4X30 3X30