# Austro Engine Engine Mandatory Service Bulletin MSB-E4-036/1: Revision 1, from page 13

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- Document: [Austro Engine Engine Mandatory Service Bulletin MSB-E4-036/1](https://openairdocs.org/service-documents/austro-engine/msb-e4-036-1.md)
- Title as filed: MSB-E4-036_rev.1
- Pages: 31
- PDF: https://openairdocs.org/files/sha256/b4/e6/b4e6f5c16cd15dbac0a44fd1539241fb21bcd396d865c41499ab7b6a0a670629
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## Text

Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 13

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 13-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
1.7. Concurrent documents / references 
  Note: If not specified, the latest revision of the referenced documents applies. 
• Maintenance Manual E4.08.04 
• Service Instruction SI-E4-016 
• Service Instruction SI-E4-018 
• Mandatory Service Bulletin MSB-E4-034 rev. 1 or subsequent approved revisions 
• Mandatory Service Bulletin MSB-E4-035 rev. 0 or subsequent approved revisions 
1.8. Other publications affected 
None 
1.9. Credits 
Inspection and replacement of the HPP driving gear on an engine, accomplished before the effective 
date of this Mandatory Service Bulletin in accordance with the instructions of MSB -E4-034 Revision 
1 or MSB-E4-035, as applicable, are acceptable to comply w ith the requirements of this Mandatory 
Service Bulletin for that engine, provided no affected cylinder head/HPP driving gear combination 
has been installed on that engine at any time after that inspection.

### Page 14

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 14-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
2. Technical Details 
2.1. Removal and inspection of the HPP driving gear 
1. Remove the HPP in accordance with the instructions in Maintenance Manual, Doc. No. 
E4.08.04, Section 73-10-03, Paragraph A. 
2. Remove the drive gear from the HPP in accordance with the instructions in Maintenance 
Manual, Doc. No. E4.08.04, Section 73-10-03, Paragraph C. 
 
Caution: Use only the tool p/n AE300T012 -1 provided in the kit of this Service Bulletin to block the gear. 
3. To remove the gear from the shaft, use a bearing extractor shown in paragraph 3.2 
4. Clean the driving gear with non -chlorinated brake cleaner (recommended product 
Manufacturer: Förch, Product ID.: R510) 
5. Visually inspect the driving gear against colour criteria  of Appendix II  Table 6; i f the 
acceptable criteria are not met: 
o remove the camshafts according to the M aintenance Manual, Doc. No. E4.08.04, 
Section 85-30-00 Subparagraph 4A (a) - (h) 
o Inspect the HPP shaft, the cylinder head, camshaft gear, the inlet/outlet camshaft 
bushing in accordance with the Appendix II of this service bulletin and replace the 
parts as necessary. 
2.2. Installation of the new HPP driving gear 
2.2.1 Driving Gear p/n E4A-30-000-201 rev. AB1 or p/n E4A-30-000-601 
 
Caution: DO NOT INSTALL the gear p/n E4A-30-000-201 rev. AB1 or E4A-30-000-601 if a Cylinder Head p/n E4A-12-500-000 is installed on the engine 
1. Install the new drive gear in accordance with the instructions in Maintenance Manual, Doc. 
No. E4.08.04, Section 73-10-03, Paragraph D (replace the nut, if required). 
  Note: Lubricate the gear and the O-ring with engine oil before installing the HPP 
 
Caution: Use only the tool p/n AE300T012-1 provided in the kit of this Service Bulletin to block the gear 
2. Install the HPP in accordance with the instructions in Maintenance Manual, Doc. No. 
E4.08.04, Section 73-10-03, Paragraph B. Refer also to  chapter 6 Table 2 for the tightening 
sequence of the screws. 
3. Mark a tool cycle on the Tool Cycle Recording Sheet and fill the execution report  (both 
included in the chapter 6 of this Service Bulletin). 
4. Do the engine ground run in accordance with the Engine Maintenance Manual 
  Note: One cycle equals the disassembly of the old gear and the installation of the new gear 
 
Caution: When the assembly tool p/n AE300T012-1 has reached 100 cycles, discard the tool

### Page 15

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 15-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
2.2.2 Driving gear p/n E4A-30-000-201 Rev. AE.1 or subsequent 
1. Install the new drive gear in accordance with the instructions in Maintenance Manual, Doc. 
No. E4.08.04, Section 73-10-03, Paragraph D (replace the nut, if required).  
 
  Note: Use a standard low-profile open-ended wrench (27 mm) instead of the special tool. 
  Note: Lubricate the gear and the O-ring with engine oil before installing the HPP 
 
2. Install the HPP in accordance with the instructions in Maintenance Manual, Doc. No. 
E4.08.04, Section 73-10-03, Paragraph B. Refer also to chapter 6 Table 2 for the tightening 
sequence of the screws. 
3. Do the engine ground run in accordance with the Engine Maintenance Manual 
2.3. Illustrations 
Provided as appendix to this service bulletin 
2.4. Mass (weight) 
Not affected 
2.5. Approval statement 
The technical content of this document is approved under the authority of the DOA  ref. EASA. 
21J.399.

### Page 16

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 16-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
3. Planning Information 
3.1. Material & Availability 
Quantity Part Description Part Number 
1 HPP Drive Gear 
E4A-30-000-601(1) or 
E4A-30-000-201 Rev. AB.1(1) or 
E4A-30-000-201 Rev. AE.1 
1 Gasket DIN7603-12x16x2.0 
1 Gasket DIN7603-A12x16-AL 
1 Holder wrench HPP AE300T012-1 
 
 
 
 
(1)Caution: DO NOT INSTALL the gear p/n E4A -30-000-201 rev. AB1 or E4A -30-000-601 if a Cylinder Head p/n E4A-12-500-000 is installed on the engine 
 
Caution: The holder wrench HPP p/n AE300T012-1 can be used for only for 100 cycles, after that the tool is not serviceable and must be scraped. 
  Note: One cycle equals the disassembly of the old gear and the installation of the new gear 
 
Figure 1 – Driving gear E4A-30-000-201 Rev. AE.1 
3.2. Special tools 
No. Description Note 
1 Holder wrench HPP This special tool is provided as part of this SB and it is limited to 100 cycles 
2 Bearing extractor Refer to Figure 2 (not part of the service bulletin kit) 
 
 
Figure 2 – Bearing extractor

### Page 17

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 17-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
3.3. Labor effort 
2 Hours for an acceptable gear up to 16 hours for a non -acceptable gear that requires additional 
inspections and/or parts replacement. The exact time depends on the components that might 
require replacement and do not include the waiting time between correspondence. 
4. Remarks 
 
 NOTE: 
 
o All measures must be carried out by a certified engine station and certified engine 
mechanics 
o The accomplishment of the instructions shown under chapter 2 must be confirmed 
in the respective engine log book 
o The accomplishment of the instructions must be carried out within the time of 
compliance according chapter 1.6 
o In case of doubt please contact the Austro Engine GmbH – After Sales Support  
(e-mail: service@austroengine.at; Tel: +43 2622 23000 2525) 
o For credit information contact Austro Engine GmbH – After Sales Support  
(e-mail: service@austroengine.at; Tel: +43 2622 23000 2525)

### Page 18

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 18-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
5. Explanatory notes 
5.1. Symbol explanation 
 
WARNING: Disregarding these safety rules can cause personal injury or even death 
 
CAUTION: Disregarding these special instructions and safety measures can cause damage to the engine or other components 
 
NOTE: Additional note or instruction for better understanding of an instruction

### Page 19

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 19-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
6. Appendix I 
Table 2 – HPP tightening sequence 
 
Figure 3 
Install the HPP tightening the screws clockwise, according to the 
Figure 3 sequence with 12 Nm.: 
- Step 1 – 1 at 50% 
- Step 2 – 2 at 50% 
- Step 3 – 3 at 50% 
- Step 4 - 1 at 100% 
- Step 5 - 2 at 100% 
- Step 6 - 3 at 100% 
 
 
CAUTION: DO NOT over torque 
 
Table 3 – HPP Wrench Cycles recording sheet 
 
HPP Wrench Cycles recording sheet 
Note: 
For each cycle, mark a cross on the corresponding box. When 100 cycles are 
reached, discard the wrench. 
1 Gear replacement (removal & installation) = 1 cycle 
1 2 3 4 5 6 7 8 9 10 
11 12 13 14 15 16 17 18 19 20 
21 22 23 24 25 26 27 28 29 30 
31 32 33 34 35 36 37 38 39 40 
41 42 43 44 45 46 47 48 49 50 
51 52 53 54 55 56 57 58 59 60 
61 62 63 64 65 66 67 68 69 70 
71 72 73 74 75 76 77 78 79 80 
81 82 83 84 85 86 87 88 89 90 
91 92 93 94 95 96 97 98 99 100 
HPP Drive gear wrench p/n

### Page 20

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 20-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
Table 4 – Service Bulletin Execution Report (SBER) 
 
Service Bulletin Execution 
Report Note: 
Aircraft owner:   
Aircraft Operator:  If different from the owner 
Aircraft:   
Aircraft Serial Number:   
Aircraft Marks:   
Engine (RH) s/n:  For single engine a/c, fill 
only one row 
Engine (LH) s/n:   
Flight Hours:   
Service center:  Company Name or 
reference of the person(s) 
performing the oil pump 
replacement 
Removed HPP Gear s/n: 
Or 
Inspected HPP p/n and s/n: 
 Refer to the figure below to 
identify the serial number 
NOTE:  A scanned version of this form must be provided to: 
service@austroengine.at 
copy to: 
support-austria@diamondaircraft.com 
support-canada@diamondaircraft.com 
support@wfjt.com 
NOTE: The original filled version of this form, must be packed with the removed gear, and 
provided to Austro Engine 
 
 
Figure 4 – Gear s/n location 
 
 
Figure 5 – HPP p/n and s/n location

### Page 21

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 21-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
7. Appendix II 
Table 5 - HPP Driving gear assembled - inspection chart 
 
Fig. 1 
 
Fig. 2 
 
Fig. 3 
 
Fig. 4 
Examples of HPP gear in acceptable conditions 
 
Fig. 5 
 
Fig. 6 
 
Fig. 7 
 
Fig. 8 
Examples of HPP gear in not acceptable condition 
 
Fig. 9 
 
Fig. 10 
 
Fig. 11 
 
Fig. 12 
Examples of HPP gear in not acceptable condition 
  
X 
X X 
X 
X X X 
X 
 
√ 
  
√ 
  
√ 
  
√

### Page 22

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 22-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
Fig. 13 
 
Fig. 14 
 
Fig. 15  Fig. 16 
Examples of HPP gear in not acceptable condition 
 
Fig. 17 
 
Fig. 18 
 
Fig. 19 
 
Fig. 20 
Examples of HPP gear in not acceptable condition 
 
 YES NO Consultation with 
AE required 
HPP Driving gear 
acceptable: 
   
Note: • The possible discoloration shown in the non-acceptable gears is 
due to high friction, which generates heat. When present, the 
typical discoloration is not homogeneous and presents different 
shades from black/blue to violet/bronze. 
• Check the gear according to the discoloration criteria provided.  
• Discoloration is clearly visible on the outer surface of the gear.  
• Check also for visible discoloration on the face of the teeth. 
• Check for excessive wear of the gear. 
 
In case of doubt, fill the Appendix III and contact Austro Engine 
 
  
X 
X X 
X 
X 
X 
X 
X

### Page 23

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 23-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
Table 6 - HPP Driving Gear Disassembled - Inspection chart 
 
Fig. 21 
 
Fig. 22 
 
Fig. 23 
 
Fig. 24 
Examples of gear in acceptable conditions 
 
Fig. 25 
 
Fig. 26 
 
Fig. 27 
 
Fig. 28 
Examples of gear in not acceptable condition 
 
Fig. 29 
 
Fig. 30 
 
Fig. 31 
 
Fig. 32 
Examples of gear in not acceptable condition 
 YES NO Consultation with AE 
required 
Part acceptable:    
Note: • The possible discoloration shown in the non-acceptable gears is due to high 
friction, which generates heat. When present, the typical discoloration is not 
homogeneous and presents different shades from black/blue to 
violet/bronze. 
• Check the gear according to the discoloration criteria provided.  
• Discoloration is clearly visible on the outer surface of the gear  and in the 
marking zone of the gear.  
• Check also for visible discoloration on the face of the teeth. 
• Check for excessive wear of the gear. 
In case of doubt, fill the Appendix III and contact Austro Engine 
 
X 
X X 
X 
X 
X X X 
 
√ 
 
√ 
 
√ 
 
√

### Page 24

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 24-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
Table 7 - Camshaft/camshaft gear - Camshaft inlet/outlet bearing - Cylinder head – HPP Shaft inspection 
chart 
 
Fig. 33 
 
Fig. 34 
 
Fig. 35 
 
Fig. 36 
Examples of normal wear of the cylinder head at camshaft bearings  
 
Fig. 37 
 
Fig. 38 
 
Fig. 39 
 
Fig. 40 
Examples of normal wear of the cylinder head at camshaft bearings 
  
 
√ 
 
√ 
 
√ 
 
√ 
 
√ 
  
√ 
  
√ 
 
√

### Page 25

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 25-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
Fig. 41 
 
Fig. 42 
 
Fig. 43 
 
Fig. 44 
Examples of excessive wear of the cylinder head at camshaft bearings 
 YES NO Consultation with AE required 
Cylinder Head 
acceptable: 
   
 The wear rate of the upper bearing segments, which are located inside the 
cylinder head cover, and upper bearing brackets is normally higher 
compared to the lower bearing surfaces. This is caused by the force of the 
valve springs applied to the camshafts. 
Examine the bearing segments at the cylinder cover and the cylinder cover 
for grooves and/or scratches detectable by finger. 
 
In case of doubt, fill the Appendix III and contact Austro Engine. 
X X X X

### Page 26

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 26-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
Fig. 45 
 
Fig. 46 
Examples of camshaft bearings in not acceptable conditions 
 
Fig. 47 
 
Fig. 48 
 
Fig. 49 
 
Fig. 50 
Examples of camshaft bearings in not acceptable conditions 
 YES NO Consultation with 
AE required 
Camshaft Bearings 
acceptable: 
   
Note:  Examine the inlet/outlet bearings of the camshafts for discoloration, 
wear, grooves detectable by finger. 
In case of doubt, fill the Appendix III and contact Austro Engine 
X 
X 
X 
X X X

### Page 27

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 27-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
Fig. 51 
 
Fig. 52 
 
Fig. 53 
Examples of camshaft in acceptable conditions 
 
Fig. 54 
 
Fig. 55 
 
Fig. 56 
Examples of camshaft in not acceptable conditions 
 
Fig. 57 
Examples of camshaft in not acceptable conditions 
 YES NO Consultation 
with AE required 
Camshaft acceptable:    
Note:  Some bearing positions show a circular discoloration; this is a normal sign 
of the oil supply bore located inside the lower bearing segment. Bearing 
surfaces are acceptable when they have: 
- a homogenous, even surface 
- no circular sensitive running mark detectable by fingernail. 
Camshafts with sensitive running marks detectable by fingernail are not 
permitted for re-use. Replace them by new ones. 
In case of doubt, fill the Appendix III and contact Austro Engine 
X 
X X X 
 
√ 
 
√ 
 
√

### Page 28

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 28-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
Fig. 58  
Fig. 59  
Fig. 60 
Examples of camshaft gear in acceptable conditions 
 
Fig. 61 
 
Fig. 62 
 
Fig. 63 
Examples of camshaft gear in acceptable conditions 
 
 
 
√ 
 
√ 
  
√ 
 
√ 
 
√ 
  
√

### Page 29

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 29-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
 
Fig. 64  Fig. 65 
Examples of camshaft gear in not acceptable conditions 
 
Fig. 66  
Fig. 67   Fig. 68 
 
Fig. 69 
Examples of camshaft gear in not acceptable conditions 
 
Fig. 70 
 
 
Fig. 71 
Examples of camshaft gear in not acceptable conditions 
 YES NO Consultation with 
AE required 
Camshaft gear 
acceptable: 
   
Note:  • Check the gear according to the discoloration criteria provided.  
• Darken gear without clear “overburn” discoloration are acceptable as it is the typical 
colour of the heat treatment of the material (e.g. figs. 61, 62, 63). 
• The possible discoloration shown in the non -acceptable gears is due to high friction, 
which generates heat. When present the typical discoloration is not homogeneous and 
presents different shades from black/blue to violet/bronze.  
• Shades of “ burnt” material are typically present on both f ace of the gear, such 
discoloration is clearly visible on the outer surface of the gear; use a magnifier, if 
required, to check the inner surface.  
• Check also for visible discoloration on the face of the teeth.  
In case of doubt, fill the Appendix III and contact Austro Engine 
 
X 
X 
X 
X X X 
X 
X

### Page 30

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 30-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
 
Fig. 72 
 
Fig. 73 
Examples of HPP Shaft in acceptable conditions 
 
Fig. 74 
 
Fig. 75 
Examples of HPP Shaft in not acceptable conditions 
 
Fig. 76  Fig. 77   Fig. 78  Fig. 79 
Examples of HPP Shaft in not acceptable conditions 
 YES NO Consultation with 
AE required 
HPP Shaft 
acceptable: 
   
Note:  • Check the shaft according to the discoloration criteria provided.  
• Shaft darken in the lower area (e.g. figs. 74 to 79). 
In case of doubt, fill the Appendix III and contact Austro Engine 
X 
X 
X X 
X 
X 
V V

### Page 31

DOA no. EASA.21J.399 
Mandatory Service Bulletin 
No. MSB-E4-036/1 
Austro Engine GmbH 
Rudolf-Diesel-Strasse 11 
A-2700 Wiener Neustadt 
Tel: +43 2622 23000 
FAX: +43 2622 23000-2711 
 
First Issue Date  Rev. No. Revision Date   Page 
30 Nov. 2021 1 14 Dec. 2021 31-31 
© 2021 by Austro Engine GmbH – AUSTRIA – www.austroengine.at 
8. Appendix III 
This form must be filled in case support for inspection is requested to Austro Engine. The form should 
be provided to Austro Engine service, within the photos of the inspected parts. Mark only the 
applicable parts. 
Aircraft Serial Number  
Engine Serial Number  
Service Contacts  
Note: please mark only one the applicable box. In case of not applicable/not performed, left the row blank 
Inspected and found: OK Not OK Pictures 
attached 
HPP Gear    
HPP Shaft    
Camshaft Gear    
Camshaft    
Cylinder Head    
Bearings    
NOTE: 
 
 
 
Filled by: (Name Surname) 
 
Date: (DD.MM.YYYY)

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