# 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.

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# 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. 3 X30 4 X30 

## 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 4 X30 3 X30