December 22, 2008 ASB-MBB-BK117-40-113 Page 1 of 4 250

1. PLANNING 1.A. Effectivity 1.A.1. Helicopters affected: All MBB-BK117, models A-1 to C-1. 1.A.2. Components affected: Holder assy 117-41140-01 (see Figure 1) or 117-41230-01 (see Figure 1) or 117-41230-03 (see Figure 1) 1.A.3. Spare Parts affected: See 1.A.2. 1.B. Reason In several cases the take-off procedure of an EC135 was accomplished with a locked cyclic stick. On the MBB BK117 similar parts are used. A locked cyclic stick may cause the helicopter to become uncontrollable. In order to prevent a helicopter take-off with a locked cyclic stick, a modification of the cyclic stick lock is accomplished with this Alert Service Bulletin. After accomplishment of this modification the cyclic stick can only be centered in the neutral position. Locking of the cyclic stick is no longer possible. 1.C. Description Remove spring from the holder assy from the cyclic stick lock. 1.D. Compliance This Alert Service Bulletin must be accomplished by 30.09.2009 at the latest. 1.E. Approval The technical content of this document is approved under the authority of DOA No. EASA.21J.034. 1.F. Manpower Requirement Approx. 0.5 man–hours for modification of the cyclic stick lock. 1.G. Material, Cost and Availability The required material must be ordered at the Interturbine company. **Date:** December 22, 2008 

# ALERT SERVICE BULLETIN **MBB-BK117**

**No.** ASB-MBB-BK117-40-113 **Subject:** Main Rotor Controls – Modification of the cyclic stick lock / centering

This document is available on the internet: www .eurocopter.com/techpubDecember 22, 2008 ASB-MBB-BK117-40-113 Page 2 of 4 1.H. Special Tools (not applicable) 1.I. Mass and Moment (not applicable) 1.J. Reference (not applicable) 1.K. Other Publications affected This Alert Service Bulletin will be incorporated in the following documents with a future revision: – MM MBB-BK 117 – MM MBB-BK 117 C-1 – IPC MBB-BK 117 – FLM MBB-BK 117 1.L. Electrical Load Data (not applicable)

2. ACCOMPLISHMENT INSTRUCTIONS 2.A. Inspections Required (not applicable) 2.B. Work Procedure 2.B.1. Modification of cyclic stick lock variant 1 or variant 2 (Figure 1): 2.B.1.1. Remove spring (3, Figure 1) from holder assy (1). Discard spring (3). 2.B.1.2. Perform functional test: – Move cyclic stick (2, Figure 1) in its neutral position. – Fold holder assy (1, Figure 1) down to the pin (5). – The holder assy (1, Figure 1) must not lock at the pin (5) and must fold up automatically. 2.B.2. Identification of the holder assy (1, Figure 1): 2.B.2.1. Clean surface to be identified in the area of the part number of the holder assy (1, Figure 1) using dry cleaning solvent (CM 202). Leave cleaned area to dry. 2.B.2.2. Using a permanent pen, write the number of this Alert Service Bulletin onto the holder assy (1, Figure 1) in the area of the part number. Protect inscription with lacquer, single-layer (CM 421). 2.B.3. Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of the helicopter.December 22, 2008 ASB-MBB-BK117-40-113 Page 3 of 4 2.C. Conclusions Immediately after the measures described in this Alert Service Bulletin have been accomplished, the pilots must be infomed of its contents and their attention must be drawn to the following: **NOTE** Move cyclic stick in its neutral position before the engines are started. The neutral position and the centering of the cyclic stick (2, Figure 1) can be achieved by folding down the holder assy (1) at the pin (5). Locking of the cyclic stick is no longer possible.

3. MATERIAL INFORMATION 3.1. Required Parts : Retrofit kit SB-117-40A-113-3.1.

No. Qty Nomenclature Part No.

1 *a.r. Dry cleaning solvent (CM 202) 2 *a.r. Lacquer, single-layer (CM 421) * Consumable material, to be ordered from the Interturbine company as required. 3.2. Discarded Parts : No. Qty Nomenclature Part No.

1 1 Spring 117-41173-01 or 117-20151.04 Discarded parts are not taken back by ECD.December 22, 2008 ASB-MBB-BK117-40-113 Page 4 of 4 Cyclic Stick Lock Figure 1 1 Holder assy 2 Cyclic stick 3 Spring 4 Bracket 5 Pin **Variant 1** (117-41230-01 or 117-41230-03) **Variant 2** (117-41140-01)

5 1 1 2 2

3 3

4 4