# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 1 of 14 2006-09-04 REVISION 01, 2006-10-18 

## Rotor Flight Control – Tail Rotor Controls – Inspection of linear transducer (LVDT COLLECTIVE) bearing and modification of rod and floor
1. Planning Information A. Effectivity (1) Helicopters affected: EC135, all models. (2) Components affected: Bearing LN9367GE6N2 Rod L671M5040205 Lever L671M5040101 Floor L533M1014101 or L533M1014102 or L533M1014103 or L533M1014104 or L533M1014105 or L533M1014106 (3) Spare Parts affected: Rod L671M5040205 Lever L671M5040101 Floor L533M1014101 or L533M1014102 or L533M1014103 or L533M1014104 or L533M1014105 or L533M1014106 B. Concurrent Requirements Not applicable.
C. Reason ECD was informed of an incident in which an impaired controllability of the tail rotor was detected. Examinations have shown that the bearing of the linear transducer was subject to binding and the control range was limited. With this Alert Service Bulletin an inspection and, if necessary, the replacement of the linear transducer bearing and the modification of the rod (21, Figure 1) and the floor shall be accomplished. D. Description Inspect bearing of the linear transducer and the lower side of the floor. If there is binding and/or chafing on the floor, replace bearing. Modify rod and floor.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 2 of 14 REVISION 01, 2006-10-18 2006-09-04 E. Compliance (1) Accomplish inspection and, if necessary, replacement of the bearing as well as modification of floor i.a.w. Section 3.A. up to and including Section 3.G. of this Alert Service Bulletin by 31.10.2006 at the latest. (2) Modification of rod i.a.w. Section 3.H. of this Alert Service Bulletin must be accomplished with the next periodical inspection (800 fh) at the latest. (3) In future, the inspection of the bearing must be repeated with every periodical inspection (800 fh). (4) Spare parts affected must be modified i.a.w. this Alert Service Bulletin before they are installed in the helicopter at the latest. F. Approval The technical content of this document is approved under the authority of DOA No. EASA.21J.034. G. Manpower – Approx. 10 man–hours for modification of rod and floor. – Approx. 13 man–hours for modification of rod and floor as well as for replacement of bearing. H. Weight and Balance Not applicable.
I. Electrical Load Data Not applicable. J. Software Accomplishment Summary Not applicable.
K. References AMM EC135.
L. Other Publications affected The changes to AMM EC135, MSM EC135, AMM EC135/635 T1 (CPDS) and to MSM EC135/635 T1 (CPDS) wich 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.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 3 of 14 2006-09-04 REVISION 01, 2006-10-18 2. Material Information A. Material – Price and Availability Information on cost and availability of required kit EC135-67A-012-2.C will be provided by ECD, Dept. Spares Order Administration on request. B. Support Information Not applicable. C. Material Necessary for Each Helicopter Retrofit kit EC135-67A-012-2.C. No. New P/N Keyword Old P/N Qty Disposition

1 LN9367GE6N2 Bearing LN9367GE6N2 1 A, C 2 EN236714018 Cotter pin EN236714018 1 A 3 LN90250615L Washer

− 1 A 4 LN9415018 Cotter pin LN9415018 2 A 5 ABS0635407 Teflon strip (0.150 m)

− 1 E 6

− Corrosion preventive paste (CM 518) − a.n.* B
7

− Adhesive (CM 671) − a.n.* B
8

− Chemical conversion material (CM 316) − a.n.* B
9

− Acetone (CM 203) − a.n.* B
10

− Lacquer (CM 4012) − a.n.* B
11

− Hardener (CM 4013) − a.n.* B
12

− Adhesive (CM 671) − a.n.* B, D

* a.n. = as needed Disposition: A = The material kit contains no standard parts (DIN, ISO, EN etc.). If this item is needed, a separate order has to be placed for it. B = Consumable material, to be ordered from the Interturbine company as needed. CM item number i.a.w. list of consumable materials in the AMM. C = Only needed, if bearing is replaced.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 4 of 14 REVISION 01, 2006-10-18 2006-09-04 D = Only needed, if floor is repaired. E = New, included in kit. D. Material Necessary for Each Spare See Section 2.C. E. Reidentified Parts After modification of the rod i.a.w. section 3.H. of this Alert Service Bulletin the part number of the rod changes from L671M5040205 to L671M5040215 and the part number of the lever changes from L671M5040101 to L671M5040102. Accomplish reidentification i.a.w. Section 3.H.(2)(c) of this Alert Service Bulletin. F. Special Tooling Not applicable.


### 3. Accomplishment Instructions A. Preliminary work steps: (1) Remove forward access cover i.a.w. AMM, 52-40-00, 4-3. (2) Remove middle cover i.a.w. AMM, 52-40-00, 4-4. (3) If installed, remove equipment plate i.a.w. AMM, 25-70-00, 4-2. B. Inspection of bearing and floor: CAUTION IF THE LINEAR TRANSDUCER (11, FIGURE 1) IS DETACHED, AVOID MOVING IT FURTHER THAN ITS NORMAL CONTROL RANGE. OTHERWISE, THE LINEAR TRANSDUCERS WILL BE DAMAGED. (1) Remove cotter pin (10, Figure 1), nut (9), washers (8) and bushing (7). Detach linear transducer (11) with washer (6) downwards. (2) Check bearing (1, Figure 2) for freedom of movement. If binding, rough or not smooth turning is detected during turning or tilting of bearing (1), the bearing (1) must be replaced. Replacement i.a.w. Section 3.C. of this Alert Service Bulletin. (3) If new signs of chafing i.a.w. Figure 4 are detected on the lower side of the floor (1, Figure 4), the bearing (4, Figure 3) must be replaced. Replacement of bearing i.a.w. Section 3.C. of this Alert Service Bulletin. (4) If the lower side of the floor (1, Figure 4) is damaged in the area of the assembly opening (with open honeycomb part and/or layer), the bearing (4, Figure 3) must be replaced and the floor must be repaired. Replacement of bearing i.a.w. Section 3.C. and repair of floor (1) i.a.w. Section 3.D of this Alert Service Bulletin.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 5 of 14 2006-09-04 REVISION 01, 2006-10-18 (5) If there is no binding on the bearing (1, Figure 2) and the floor (1, Figure 4) has no new signs of chafing i.a.w. Figure 4 and is not damaged in the area of the assembly opening, proceed i.a.w. Section 3.E. of this Alert Service Bulletin. C. Replacement of bearing (4, Figure 3): (1) Remove lockwire from nuts (1, Figure 3). (2) Remove nuts (1, Figure 3) and detach plate (2) from linear transducer (3). Protect linear transducers (3) from damage with suitable measures. (3) Replacement of bearing (4, Figure 3) i.a.w. AMM, 20-00-00, 2-14. NOTE Nuts (1, Figure 3) will finally be tightened and secured only when the linear transducers (3) are adjusted. (4) Put linear transducers (3, Figure 3) through plate (2). Loosely screw nuts (1) onto linear transducers, so that linear transducers (3) do not slip out of the plate (2). (5) Adjust linear transducers i.a.w. AMM, 76-10-00, 5-3. (6) Actuate tail rotor pedals and check tail rotor controls for free and smooth movement. By doing so, especially check transducer linkage rod (19, Figure 1) and rod (21) for freedom of movement. (7) After completion of work, accomplish inspection for foreign matter and objects. (8) If the floor (1, Figure 4) has no new signs of chafing, proceed i.a.w. Section 3.F of this Alert Service Bulletin. D. Repair of floor (1, Figure 4): NOTE If honeycomb part/layer is damaged within an area of more than 2 cm by 6 cm, contact ECD customer support. (1) If necessary, carefully remove protruding burr from the area around the edge of the assembly opening using a file. Remove chips. (2) Fill up floor honeycomb part (1, Figure 4) with adhesive (CM 671). E. Affixing of teflon strip (2, Bild 6): CAUTION WHEN PROCESSING THE ADHESIVE COMPLY WITH THE MANUFACTURER‘S INSTRUCTIONS. (1) Using abrasive paper, roughen bonding surface on the lower side of the floor (1, Figure 6), clean with acetone (CM 203) and leave to air. (2) Using abrasive paper, roughen brown side of teflon strip (2, Figure 6), clean with acetone (CM 203) and leave to air.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 6 of 14 REVISION 01, 2006-10-18 2006-09-04 (3) Affix teflon strip (2, Figure 6) i.a.w. figure 6 to the lower side of the floor (1) in parallel to the floor edge. By doing so, evenly apply adhesive to the brown side of the teflon strip (2) and to the floor (1). Using a suitable aid, press teflon strip (2) onto the floor (1). Carefully remove surplus adhesive and allow the bonding to cure i.a.w. the manufacturer‘s instructions. (4) Identification of floor: (a) Using acetone (CM 203), remove grease and dirt from the surface to be marked in the immediate vicinity of the teflon strip (2, Figure 6) on the lower side of the floor (1) and leave to air. (b) Using a permanent marker, identify accomplishment of this Alert Service Bulletin by marking the Alert Service Bulletin number to the immediate vicinity of the teflon strip (2, Figure 6). (c) Protect marking by means of lacquer (CM 4012, CM 4013). F. Final work steps: (1) Slide washer (6, Figure 1) and linear transducer (11) onto rod. Attach linear transducer with bushing (7), washer (8) and nut (9). Tighten nut (9) only until attachment hardware is free from play. Secure nut (9) with cotter pin (10). (2) After completion of work, accomplish inspection for foreign matter and objects. (3) If removed, install equipment plate i.a.w. AMM, 25-70-00, 4-2. (4) Install middle cover i.a.w. AMM, 52-40-00, 4-4. (5) Install forward access cover i.a.w. AMM, 52-40-00, 4-3. G. Confirm accomplishment of Section 3.A up to and including Section 3.F of this Alert Service Bulletin by an entry in the historical record of the helicopter. H. Modification of rod (21, Figure 1). NOTE Accomplish modification of rod by the next periodical inspection at the latest. (1) Removal of rod: (a) Remove cover cap (1, Figure 1) from floor (3) and align rod (21) so that screw (22) can be removed through the assembly opening in the floor (3). Store cover cap (1) for reuse. CAUTION IF THE TRANSDUCER LINKAGE ROD (19) IS DETACHED, AVOID MOVING ROD (21) FURTHER THAN ITS NORMAL CONTROL RANGE. OTHERWISE, THE LINEAR TRANSDUCERS LVDT COLLECTIVE (11) WILL BECOME DAMAGED.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 7 of 14 2006-09-04 REVISION 01, 2006-10-18 (b) Remove cotter pin (16, Figure 1), nut (15), washers (17, 20) and screw (22). Disconnect transducer linkage rod (19) from rod (21). Protect transducer linkage rod (19) from damage with suitable measures. (c) Remove cotter pin (10, Figure 1), nut (9), washers (6, 8) and bushing (7). Pull rod (5) out of plate (12). (d) Remove cotter pin (14, Figure 1), nut (13), washer (4) and screw (2). Remove rod (21) from floor (3). (2) Modification and reidentification of rod (1, Figure 5):
CAUTION DURING LOWERING, ENSURE NOT TO LOWER SCREW HEAD MORE THAN 0.2 MM THAN THE SURFACE OF THE ROD (1, FIGURE 5) IS. (a) Using a 100 degree countersink, lower borehole of rod (1, Figure 5) until screw head of screw (2) is flush with the surface of the rod (1). (b) Re–establish surface protection using chemical conversion material (CM 316) and leave to dry i.a.w. the manufacturer‘s instructions. (c) Reidentification of rod and lever: 1 Using a black permanent marker, cross out old part number L671M5040205 of rod (1, Figure 5) and old part number L671M5040101 of lever but leave them still legible. 2 Using a black permanent marker, write new part number L671M5040215 of rod (1, Figure 5) and new part number L671M5040102 of lever to the immediate vicinity of the old part numbers and protect by means of lacquer (CM 4012, CM 4013). (3) Installation of rod (21, Figure 1): (a) Position rod (5, Figure 1) together with washers (6, 8), bushing (7) and nut (9) in plate (12). T ighten nut (15) only to such an degree that attachment hardware is free from play. Secure nut (9) with cotter pin (10). (b) Apply corrosion preventive paste (CM 518) onto screw (2, Bild 1). Position rod (21) on floor (3) and attach to floor (3) by means of screw (2), washer (4) and nut (13). Torque–tighten nut (13) to 1–1.5 Nm and secure with cotter pin (14). (c) Apply corrosion preventive paste (CM 518) onto screw (22, Figure 1) and align rod (21) so that screw (22) can be put through the assembly opening in the floor (3). (d) Attach transducer linkage rod (19, Figure 1) to rod (21) with screw (22), washers (17, 20), additional washer (18) and nut (15). Tighten nut (15) only to such an degree that attachment hardware is free from play. Secure nut (15) with cotter pin (16).

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 8 of 14 REVISION 01, 2006-10-18 2006-09-04 (e) Close assembly opening in the floor (3, Figure 1) with cover cap (1). By doing so, insert cover cap (1) from the upper side of the floor. (f) Actuate tail rotor pedals and check tail rotor controls for free and smooth movement. By doing so, especially check transducer linkage rod (19, Figure 1) and rod (21) for freedom of movement. (4) Confirm accomplishment of Section 3.H. of this Alert Service Bulletin by an entry in the historical record of the helicopter.


### 4. Appendix Not applicable.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 9 of 14 2006-09-04 REVISION 01, 2006-10-18 Removal/Installation of Rod Figure 1 1 Cover cap 2 Screw 3 Floor 4 Washer 5 Rod 6 Washer 7 Bushing 8 Washer 9 Nut 10 Cotter pin 11 Linear Transducers 12 Plate 13 Nut 14 Cotter pin 15 Nut 16 Cotter pin 17 Washer 18 Washer LN9025-0615L 19 Transducer linkage rod 20 Washer 21 Rod 22 Screw 1 2

3

4

5

6

7 8

9

10 11 12 11 13 14 16 17 19 20 21 22

After modification. 1–1.5 Nm

Assembly opening. 15 18

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 10 of 14 REVISION 01, 2006-10-18 2006-09-04 Inspection of Bearing Figure 2 1 Bearing 2 Linear Transducers 1

2 2

Inspect bearing for binding, rough or not smooth turning by turning and tilting bearing.

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 11 of 14 2006-09-04 REVISION 01, 2006-10-18 Replacement of Bearing Figure 3 1 Nut 2 Plate 3 Linear Transducers 4 Bearing LN9367GE6N2 1

1 3

2 3 4

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 12 of 14 REVISION 01, 2006-10-18 2006-09-04 Lower Side of Floor Figure 4 1 Floor 2 Rod 3 Transducer linkage rod Possible chafing. 1

2

3

Assembly opening. View on lower side of floor. FLIGHT DIRECTION

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 13 of 14 2006-09-04 REVISION 01, 2006-10-18 Modification of Rod Figure 5 1 Rod 2 Screw 3 Rod 1 2 2

Using a 100 degree countersink, lower borehole of rod (1) until screw head of screw (2) is flush with the surface of the rod (1). Chemical conversion material (CM 316). Part number of lever (lower side of part). Part number of rod (1). 1

3

Lever consists of rod (1) and rod (3). L671M50401XX

# ALERT SERVICE BULLETIN EC135

EC135-67A-012 PAGE 14 of 14 REVISION 01, 2006-10-18 2006-09-04 Modification of Floor Figure 6 1 Floor 2 Teflon strip Lower side of floor 1

2

Assembly opening

Affixed with adhesive (CM 671). All dimensions in mm.

Identify with the number of the Alert Service Bulletin. ASB EC135-67A-012 FLIGHT DIRECTION