# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **Effective for version(s): T2+, P2+, 635 T2+, 635 P2+**



# EMERGENCY 

# ALERT SERVICE BULLETIN

**SUBJECT**

**: AIR CONDITIONING -- Mechanical air conditioning Inspection of the compressor bearing block** 

**Revision number Issue date**  Revision 0 2011-06-06 **Summary: During the preflight check metallic parts have been found within the area of the air inlets of both**  **engines. The following inspection showed that these parts were parts of the bearing cage of one of the ball bearings of the air conditioning compressor bearing block. Loose parts of the bearing cage**  **have damaged the compressor stage of one of the two engines to such an extent that a basic overhaul was necessary. Therefore, this Alert Service Bulletin specifies an inspection of the affected ball**  **bearing. Compliance:**  **Compliance with this Alert Service Bulletin is prescribed. See Section 1.E.**

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **1. PLANNING INFORMATION 1.A. EFFECTIVITY**  **1.A.1. Helicopters/installed equipment (a) EC135/EC635, all models with mechanical air conditioning S/N 870, 872, 873, 879, 883,**  **884, 888, 893, 900, 905, 911, 914, 916, 917, 923, and 926.** **(b) Compressor bearing block P/N L210M1872105*.** *** The part number is on the place identified on Figure 1. Compressor bearing blocks L210M1872106 and L210M1872107 are not affected.**  

## 1.A.2. Non--installed equipment **Not applicable 1.B. ASSOCIATED REQUIREMENTS**  **Not applicable. 1.C. REASON**  **During the preflight check metallic parts have been found within the area of the air inlets of both engines. The following inspection showed that these parts were parts of the bearing cage of one**  **of the ball bearings of the air conditioning compressor bearing block. Loose parts of the bearing cage have damaged the compressor stage of one of the two engines to such an extent that a basic**  **overhaul was necessary. Therefore, this Alert Service Bulletin specifies an inspection of the affected ball bearing.**  **1.D. DESCRIPTION Remove LH and RH transmission fairings. Open bearing block cover. Inspect bearing for**  **condition. If necessary, deactivate air conditioning. 1.E. COMPLIANCE**  **1.E.1. Compliance at the works Not applicable.**  **1.E.2. Compliance in service Helicopters/installed**  **equipment: (a) The upper bearing must be inspected i.a.w. Section 3.B.2 within 25 fh after receipt of this**  **Alert Service Bulletin, but by June 30, 2011 at the latest. (b) If water or corrosion is detected during the inspection i.a.w. Section 3.B.2 deactivate the**  **air conditioning i.a.w. Section 3.B.3. (c) If no water or corrosion is detected during the inspection i.a.w. Section 3.B.2 this inspection**  **must be repeated every 100 fh (with a tolerance range of +/--10 fh) but after 3 months at the latest.** 

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **(d) If only condensation moisture (without formation of troplets) is detected during the inspection i.a.w. Section 3.B.2 the inspection must be repeated every 25 fh (with a**  **tolerance range of +/-- 2.5 fh) but after 4 weeks at the latest. Non--installed**  **equipment: Not applicable.**  **1.F. APPROVAL Approval of this**  **document: The technical content of this document is approved under the authority of**  **DOA No. EASA.21J.034. 1.G. MANPOWER**  **Qualification Mechanic**  **Electrician Pilot**  **Others Time**  for Section 3.B.2 approx. 4 h 0 h 0 h 0 h Time for Section 3.B.3 approx. 6 h 0 h 0 h 0 h
**1.H. WEIGHT AND BALANCE Not applicable.**  **1.I. EFFECT ON ELECTRICAL LOADS Not applicable.**  **1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD Not applicable.**  **1.K. REFERENCES Not applicable.**  **1.L. OTHER DOCUMENTS AFFECTED AMM EC135 and AMM EC135/635.**  **1.M.INTERCHANGEABILITY OR MIXABILITY OF PARTS Interchangeability:**  **Not applicable. Mixability:**  **Not applicable.**

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **2. MATERIAL INFORMATION 2.A. MATERIAL: PRICE -- AVAILABILITY -- PROCUREMENT**  **Not applicable. 2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT**  **Not applicable. 2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONENT**  **Kits or components to be ordered for one helicopter or one assembly:**  **Material kit SB-135-21A-013-2C. No.**  **Keyword Qty**  **New P/N Old P/N**  **Remark** 1 O--ring 1 0634313273 0634313273
-- 2 Hexagon nut 6 LN9338--06 LN9338--06
-- **Consumable material to be ordered separately:**  **Consumable materials must be separately ordered at the INTERTURBINE AVIATION LOGISTICS company. The given CM -numbers are i.a.w. the AMM List of Consumable Materials.**  **Website: http://www.interturbine.com Tel.: +49.41.91.809.300**  **AOG: +49.41.91.809.444 No.**  **Keyword Qty**  **Material part number**  **CM Remark** 
1 Acetone a.n.* FED O--A--51 TL 6810--003 203

-- 2 Lockwire, Ø 0.63 mm a.n.* LN9424--1.4546.9--0,63 775 --
3 Corrosion preventive paste a.n.* ECD CODE 62888 / 54456 MIL--PRF--8116 WL 5.7070.0 CMS N4911651774 LN9368--5903 518

--

4 Sealing compound a.n.* WL 5.5905.2 ECD CODE 810421 CMS N4915080001 6050

-- 5 Sealing compound a.n.* ECD CODE 658971 WL 5.5904.2 6056

-- *a.n. = as needed **2.D. MATERIAL TO BE RETURNED Not applicable.** 

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **3. ACCOMPLISHMENT INSTRUCTIONS 3.A. GENERAL INFORMATION**  **Not applicable. 3.B. OPERATIONAL PROCEDURE**  **3.B.1. Preliminary steps:**  **(a) Remove the LH and RH transmission fairing i.a.w. AMM, 71--11--00, 4--4. 3.B.2. Inspect**  **bearing: NOTE** 

**On helicopters with sand filter the rotor mast seal must be removed previously. (a) Remove lockwire (1, Figure 2).**  **(b) Remove screws (2) and washers (3). (c) Remove cover (4).**  **(d) Accomplish a visual inspection of the bearing and the bearing housing for humidity and**  **corrosion. (e) If signs of water or corrosion are detected, proceed i.a.w. Section 3.B.3.**  **NOTE If necessary, use a flashlight.**  **(f) If no signs of water or corrosion are detected, proceed as follows: 1**  **Clean sealing surface on the cover (4) and on the compressor bearing block using**  **a lint--free cloth and acetone (CM 203). 2**  **Leave cleaned areas to air for approx. 10 minutes. 3**  **Apply sealing compound (CM 6056) and fit cover (4). 4**  **Apply corrosion preventive paste (CM 518) onto screws (2) and secure cover (4) using screws (2) and washers (3). Tightening torque of the screws: 4--5 Nm.**  **5 Safety screws (2) with lockwire (CM 775) i.a.w. Figure 2.**  **3.B.3. Deactivate air conditioning:**  **NOTE**

**On helicopters with sand filter the rotor mast seal must be removed previously. (a) Remove the screw (2, Figure 3) installed on the LH aft side, as seen into forward flight**  **direction, together with washers (3), nut (6) and the bracket (4) of the brake line (5). (b) Remove the screw (12) installed on the RH aft side, as seen into forward flight direction,**  **together with washers (3, 14), nut (6) and grounding strip (13).**

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **(c) Remove the nuts (6) together with washers (3) from the LH and RH aft threaded bolt. (d) Remove the nut (6) installed on the RH forward side, as seen into forward flight direction,**  **together with the washer (3) from the threaded bolt. (e) Remove the screw (6) installed on the LH forward side, as seen into forward flight direction,**  **together with washer (3) and the bracket (10) of the brake line (5) from the LH forward threaded bolt.**  **(f) Discard all removed 6 nuts (6). (g) Set brake line (5) aside.** 
**CAUTION IF THE COMPRESSOR BEARING BLOCK (1) TILTS, THE CONNECTING SHAFT (9) MIGHT**  **GET DAMAGED. CAREFULLY LOOSEN THE COMPRESSOR BEARING BLOCK (1)! (h) The bearing block is installed with sealing compound. If necessary, detach the compressor**  **bearing block (1) from the flange (7) on the main transmission using plastic wedges and with slight hammer strokes.**  **(i) Lift the compressor bearing block (1) and keep it at a certain distance towards the main transmission using tensioning straps.**  **(j) Remove connecting shaft (9). (k) Remove the O--ring (8) on the lower side of the compressor bearing block (1) from the**  **centering seat and discard. (l) Apply lubricating oil CM 103 or lubricating oil CM 1001 onto new O--ring (8) and install it**  **to the lower side of the compressor bearing block (1) in the groove of the O--ring on the centering seat.**  **(m) Clean flange (7) on the main transmission and on the compressor bearing block (1) using a lint--free cloth and acetone (CM 203).**  **(n) Leave cleaned area to air for approx. 10 minutes. (o) Evenly apply corrosion preventive paste (CM 518) onto the flange (7) of the main**  **transmission and onto the four threaded bolts. (p) Position the compressor bearing block (1) onto the flange (7) of the main transmission.**  **While doing so ensure that: 1**  **The four forward boreholes in the flange of the compressor bearing block (1) align with the four threaded bolts on the flange (7) of the main transmission.**  **2 The two aft boreholes in the flange of the compressor bearing block (1) align with the**  **boreholes on the flange (7) of the main transmission. (q) The previously discarded nuts (6) are replaced by 6 new nuts (6).** 

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **(r) Using nut (6) and washer (3), secure the bracket (10) on the threaded bolt installed on the LH forward side, as seen into forward flight direction.**  **(s) Torque--tighten nut (6) to 9 Nm -- 10 Nm. (t) Install nut (6) and washer (3) onto the threaded bolt installed on the RH forward side, as**  **seen into forward flight direction. (u) Torque--tighten nut (6) to 9 Nm -- 10 Nm.**  **(v) Install nuts (6) and washers (3) onto the two remaining threaded bolts. (w) Torque--tighten nuts (6) to 9 Nm -- 10 Nm.**  **(x) Using screw (2), washers (3) and nut (6), secure the bracket (4) of the brake line (5) to the borehole on the LH aft side, as seen into forward flight direction. While doing so, install the**  **screw (2) with corrosion preventive paste (CM 518). (y) Torque--tighten screw (2) and nut (6) to 9 Nm -- 10 Nm.**  **(z) Using grounding strip (13), screw (12), washers (3, 14) and nut (6), prepare the grounding connection i.a.w. AMM, 20--00--00, 2--21. Install the screw (12) with corrosion preventive**  **paste (CM 518). (aa) Torque--tighten screw (12) and nut (6) to 9 Nm -- 10 Nm.**  **(ab) Remove protruding corrosion preventive paste (CM 518) from flange (7) of the main transmission.**  **(ac) Remove protruded corrosion preventive paste (CM 518) also from the inner contour of the compressor bearing block (1).**  **(ad) Thoroughly clean the area around the flange (7) using a lint--free cloth and acetone (CM 203).**  **(ae) Leave cleaned area to air for approx. 10 minutes. (af) Seal inner area of the compressor bearing block (1):**  **1 Apply CM 5003 corrosion preventive paste onto the surface of the main transmission**  **and onto the inner contour of the compressor bearing block (1). Leave to dry i.a.w. the manufacturer’s instructions.**  **2 Apply CM 526 corrosion preventive paste onto the surface of the main transmission**  **and onto the inner contour of the compressor bearing block (1). Leave to dry i.a.w. the manufacturer’s instructions.**  **(ag) Protect grounding connection i.a.w. AMM, 20--00--00, 2--21. (ah) Apply a sealing compound bead (CM 6050) around the outer contour of the flange (7).**  **(ai) Let sealing compound dry i.a.w. the manufacturer’s instructions. (aj) 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 fact that the air conditioning is deactivated.** 

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **3.B.4. Final steps**  **NOTE**

**On helicopters with sand filters the rotor mast seal must be re--installed. (a) Install the LH and RH transmission fairing i.a.w. AMM, 71--11--00, 4--4.**  **3.C. IDENTIFICATION Accomplishment of this**  **document: Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of the**  **helicopter.**


## 4. APPENDIX **Not applicable.**

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **Part Number on the Bearing Block Figure 1**  

## View 

# A

**1 Bearing block 1** 

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **Inspection of Upper Bearing**

**Figure 2 1 Lockwire (CM 775)**  **2 Screw 3 Washer**  **4 Cover Visual inspection of the bearing housing and the**  **ball bearing for humidity and corrosion. Sealing surface of cover**  **1 2, 3**  **4**

**x4**

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# ASB **EC135-21A-013**

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## Revision 0, 2011-06-06 **Removal of Connecting Shaft Figure 3**  

## View 

# A

**View B**  

# B

**View C**  **1 Compressor bearing block 2 Screw**  **3 Washer 4 Bracket**  **5 Brake line 6 Nut**  LN9338--06 **7 Flange 8 O--ring**  0634313273 **9 Connecting shaft 10 Bracket**  **11 Not applicable 12 Screw**  **13 Grounding strip 14 Washer** 

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