December 19, 2008 ASB BO105-40-106

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1. PLANNING

1.A. Effectivity

1.A.1. Helicopters affected: All BO105 helicopters (including BO105 CBS-5 KLH), 

excluding BO105 CB-3.

1.A.2. Components affected: Cantilever assy 105-40132 (see Figure 1) or

105-40139 (see Figure 1)

1.A.3. Spare Parts affected: See 1.A.2.

1.B. Reason

In several cases it happened that the take-off procedure of an EC135 was

accomplished with a locked cyclic stick. On the BO105 similar parts are used. A locked

cyclic stick can 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 its

neutral position. Locking of the cyclic stick is no longer possible.

1.C. Description

1.C.1. If cantilever assy 105-40139 is installed, remove the spring at the cyclic stick lock

cantilever.

1.C.2. If cantilever assy 105-40132 is installed, remove the locking plate at the cyclic stick.

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 the modification of the cyclic stick lock.

Date: December 19, 2008

ALERT SERVICE BULLETIN

BO105

No. ASB BO105-40-106

Subject: Main Rotor Controls – Modification of the cyclic stick lock / centering
ASB BO105-40-106 December 19, 2008

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1.G. Material, Cost and Availability

The required material must be ordered at the Interturbine company.

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 BO105

– TM 1(4)-1520-302-23-4

– IPC BO105

– TM 1(4)-1520-302-23-P

– FLM BO105

1.L. Electrical Load Data

(Not applicable)

2. ACCOMPLISHMENT INSTRUCTIONS

2.A. Inspections Required

On helicopters up to and including serial number S40, check, whether the cyclic stick

cantilever folds back automatically (see Service Bulletin 40-18). 

If the cyclic stick cantilever does not automatically fold back, Service Bulletin 40-18

must be simultaneously accomplished with this Alert Service Bulletin.

2.B. Work Procedure

2.B.1. Check, which cyclic stick lock variant is installed (see Figure 1):

2.B.1.1. If cyclic stick lock variant 1 is installed, proceed i.a.w. Section 2.B.2.

2.B.1.2. If cyclic stick lock variant 2 is installed, proceed i.a.w. Section 2.B.3.

2.B.2. Modification of cyclic stick lock variant 1 (Figure 2):

2.B.2.1. Using a suitable drift punch, punch out shear pin (4, Figure 2) and remove locking

plate (3) together with shear pin (4). While doing so, ensure that shear pin (4) and

locking plate (3) do not fall down.
December 19, 2008 ASB BO105-40-106

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2.B.2.2. Discard shear pin (4, Figure 2) and locking plate (3).

2.B.2.3. Perform functional test:

– Move cyclic stick (2 Figure 2) in its neutral position.

– Fold cantilever (1, Figure 2) down to the pin (5).

– The cantilever (1, Figure 2) must not lock at the pin (5) and must fold up

automatically.

2.B.2.4. Identification of the cyclic stick (2, Figure 2):

– Clean surface to be identified in the area of the pin (5, Figure 2) using dry

cleaning solvent (CM 202). Leave cleaned area to air.

– Using a permanent pen, write the number of this Alert Service Bulletin onto

cyclic stick (2, Figure 2) near the pin (5). Protect inscription with lacquer,

single-layer (CM 421).

2.B.2.5. Proceed i.a.w. Section 2.B.4.

2.B.3. Modification of cyclic stick lock variant 2 (Figure 3):

2.B.3.1. Remove spring (2, Figure 3) from bracket (3). Discard spring (2).

2.B.3.2. Perform functional test:

– Move cyclic stick (5, Figure 3) in its neutral position.

– Fold cantilever (1, Figure 3) down to the pin (4).

– The cantilever (1, Figure 3) must not lock at the pin (4) and must fold up

automatically.

2.B.3.3. Identification of the cantilever (1, Figure 3):

– Clean surface to be identified in the area of the part number on the cantilever

(1, Figure 3) using dry cleaning solvent (CM 202). Leave cleaned area to air.

– Using a permanent pen, cross out the old part number of the cantilever

(1, Figure 3) and write new part number 105-40158 onto cantilever (1). Protect

inscription with lacquer, single-layer (CM 421).

2.B.4. Confirm accomplishment of this Alert Service Bulletin by an entry in the historical

record of the helicopter.

2.C. Conclusions

Immediately after accomplishment of the measures of this Alert Service Bulletin the

pilots must be informed 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 (3, Figure 1)

can be achieved by folding down the cantilever (1) at the pin (2). 

Locking of the cyclic stick is no longer possible.
ASB BO105-40-106 December 19, 2008

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3. MATERIAL INFORMATION

3.1. Required Parts per helicopter:

Retrofit kit SB-105-40A-106-3.1.

No. Qty Nomenclature Part No.

1 *a.r. Dry cleaning solvent (CM 202)

2 *a.r. Lacquer, single-layer (CM 421)

3.2. Discarded Parts:

No. Qty Nomenclature Part No.

1 1 Spring 105-20151.04 (**)

2 1 Locking plate 105-40141.07 (***)

3 1 Shear pin 105-40141.12 (***)

Discarded parts are not taken back by ECD.

* Consumable material, to be ordered from the Interturbine company as required.

** If cantilever assy 105-40139 is installed.

***If cantilever assy 105-40132 is installed.
December 19, 2008 ASB BO105-40-106

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Cyclic Stick Lock

Figure 1

1 Cantilever

2 Pin

3 Cyclic stick

Variant 1

(105-40132)

Variant 2

(105-40139)

1

2

3
ASB BO105-40-106 December 19, 2008

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Cyclic Stick Lock (Variant 1)

Figure 2

1 Cantilever

2 Cyclic stick

3 Locking plate

4 Shear pin

5 Pin

1

2

3

5

4
December 19, 2008 ASB BO105-40-106

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Cyclic Stick Lock (Variant 2)

Figure 3

1 Cantilever 105-40139

105-40158

2 Spring

3 Bracket

4 Pin

5 Cyclic stick

1

2

3

4

5

Before modification.

After modification.