Rotax 912 Series Service Bulletin

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SB-912-079

Essential information regarding engine installation, operation,

and maintenance for ROTAX

ATA System: 72-00-00 Engine

MANDATORY

1) Planning information

To obtain satisfactory results, procedures specified in this publication must be accomplished with

accepted methods in accordance with prevailing legal regulations.

BRP-Rotax GmbH & Co KG cannot accept any responsibility for the quality of work performed in

accomplishing the requirements of this publication.

1.1)

Applicability

All versions of ROTAX

912 S/ULS (Series)

1.2)

Concurrent ASB/SB/SI and SL

In addition to this Service Bulletin / Service Letter / Service Instruction the following documents

must be observed and complied with:

- SI-912-016 / SI-914-019, "Selection of suitable operating fluids for ROTAX

915 i, 912 and 914 (Series)".

- SL-916 i-009/915 i-011/912 i-005/912-014/914-012, Non-approved modifications or use of

ROTAX® unapproved engine components or accessories for ROTAX

- SB-912-044 - Use of the ROTAX® supplied airbox for all ROTAX

(Series).

- SI-03-1998 - Engine start at low temperatures at ROTAX

- in general, all relevant Alert Service Bulletins (ASB), Service Bulletins (SB), Service Instruc-

tions (SI), Service Letters (SL), Service Instruction - Parts and Accessories (SI-PAC) with rele-

vance to perform this maintenance, repair or overhaul task.

1.3)

Reason

Field observations that are carried out as part of our obligations revealed an increased number of

unexplainable engine power losses, engine vibrations, and piston damage. In-depth investigations

on various aircraft models have identified the main contributing factors and causes for the majority

of these occurrences. The findings and insights of these investigations are hereby shared with all

stakeholders. It is also pointed out that these guidelines and requirements must be observed.

1.4)

Subject

Essential information regarding engine installation, operation, and maintenance for ROTAX

(Series) Aircraft Engines.

11 November 2024

Initial Issue

912 (Series) Aircraft Engines

engine types:

Engine type

all

Current valid documentation see:

www.flyrotax.com

SERVICE BULLETIN

Serial number

Engine Type 912 i,

Aircraft Engines.

Engine Types 912 A/F

Engine Type 912 and 914 (Series).

912

72-00-00

Page 1 of 35

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Summary of Contents for Rotax 912 Series

Page 1 To obtain satisfactory results, procedures specified in this publication must be accomplished with accepted methods in accordance with prevailing legal regulations. BRP-Rotax GmbH & Co KG cannot accept any responsibility for the quality of work performed in accomplishing the requirements of this publication.
Page 2 12 months after publication of this Service Bulletin. Operators / Pilots requirements: - Check for compliance with applicable guidelines and requirements in your area of account- ability - with the next 10 hours. In case of non-compliance or questions contact a ROTAX ® authorized distributor.
Page 3 ROTAX website: ® www.flyrotax.com. Updates and current revisions can be downloaded for free. 1.12) Other Publications affected None. 11 November 2024 72-00-00 Initial Issue Page 3 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 4 - Persons approved by the respective Aviation Authorities. NOTE: Indicates supplementary information which may be needed to fully complete or under- stand an instruction. All work has to be performed in accordance with the relevant ROTAX Instructions for ® Continued Airworthiness (ICA) of the respective engine type.
Page 5 3.16 Engine starting and shutdown procedure and tips 3.17 Differential & crankcase pressure check 3.18 Selection of pistons and cylinders 11 November 2024 72-00-00 Initial Issue Page 5 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 7 ® release of BRP-Rotax GmbH & Co KG. These lines must not be routed into the slipstream. If the drainage lines of the airbox are connected with the drainage lines of the drip trays or the carburetors by a T-piece, these lines must not be routed down the firewall (drainage lines of the airbox separately are allowed).
Page 8 (e.g. for disconnections, leakages, no kink, porosity, disconnected line, wrongly routed line,..). These influence the air-to-fuel ratio drastically and must be kept in proper working order. 11 November 2024 72-00-00 Initial Issue Page 8 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 9 Exhaust systems with back pressure measurement(s) beyond the limits outlined in the lat- est Installation Manual (IM) of the respective engine types, must not be used with ROTAX aircraft ®...
Page 11 If in doubt use higher octane fuels. Recommend minimum RON 98 fuel in Aircraft Flight Manual (AFM) / Pilot Operating Handbook (POH) for high load applications (See section 3.5.1)). 11 November 2024 72-00-00 Initial Issue Page 11 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 12 *for specification of fuel types see Service Instruction SI-912-016 / SI-914-019 / SI-912 i-001 / SI-915 i-001 / SI-916 i-001, “Selection of suitable operating fluids for ROTAX® Engine Type 916 i (Series), 915 i (Series), 912 i (Series), 912 and 914 (Series)”.
Page 13 Red arrows describe the way it should not be done. Green arrows CAUTION WARNUNG describe the right way Fig. 2 Power increase 11 November 2024 72-00-00 Initial Issue Page 13 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 14 Make sure to adjust ground adjustable fixed-pitch and constant-speed propellers in accordance with the latest applicable maintenance manual and assure sufficient high engine/propeller RPM at take-off power. 11 November 2024 72-00-00 Initial Issue Page 14 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 15 3.5.3) Operator requirements In case of high engine load applications opt for minimum RON 98 fuels. 3.5.4) Maintenance requirements None. 11 November 2024 72-00-00 Initial Issue Page 15 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 16 Intake air heat up - Carb. heat bypass, Airbox temperature, Engine compartment ventilation 3.6.1) Background information The air intake system is determined essentially by the demands of engine and of the acceptable noise emission on the intake side. An airbox can be supplied by ROTAX as an option. ®...
Page 17 SB-912-079 SERVICE BULLETIN ROTAX® strongly recommends additional to minimum required instrumentation the installation as per latest Installation Manual (IM) of: - An airbox temperature sensor (see as well section 3.14.2)). NOTE: This does offer the possibility to constantly monitor the MAT temperature and eventu- ally identify issues (leaking carb heat, disconnected intake pipes,...) before they will...
Page 18 It is not permitted to partially activate the carb. heat system. The carb. CAUTION WARNUNG heat system has to be either activated/on or deactivated/off com- pletely. Intermediate positions of the throttle valves in the ROTAX gen- ® uine airbox may lead to a separation of the "hot" and the "fresh" air in the airbox which consequently leads to the provision of too hot air to one carburettor and fresh unheated air to the other carburettor.
Page 19 - Verify the correct purging of the coolant system in accordance with OEM's AMM instructions. - Verify the Coolant Temperature (CT) limits reached in the last flights. 11 November 2024 72-00-00 Initial Issue Page 19 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 20 For specifying the approved fuel types for the aircraft in the respective Aircraft Flight Manual (AFM) / Pilot Operating Handbook (POH) or equivalent, please refer to SI-912-016 / SI-914-019 / SI- 912 i-001 / SI-915 i-001 / SI- 916 i-001, "Selection of suitable operating fluids for ROTAX Engine ®...
Page 21 - In case of the combination of lower octane fuels and evidence of contributing factors (see sec- tion 3.1) please advise the operator to change over to minimum RON 98 fuels. 11 November 2024 72-00-00 Initial Issue Page 21 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 22 Ignition system - Easy-start activation, Trigger coil gap, Temp. influence 3.10.1) Background information The ROTAX engines of 912 Series are equipped with a breakerless dual ignition system (DCDI- ® Dual Capacitor Discharge Ignition). The ignition unit needs no external power supply. Each of the two independent charging coils located on the generator stator supplies one of two ignition cir- cuits.
Page 23 3.10.3) Operator requirements Do not attempt to intentionally activate the easy-start function except when starting the engine. 11 November 2024 72-00-00 Initial Issue Page 23 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 24 The trigger coil gap is factory preset and within normal usage there is no need to adjust it. Fig. 5 11 November 2024 72-00-00 Initial Issue Page 24 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 25 Do use correct quantity of heat conduction compound. Excessive use of heat conduction compound could lead to the effect of contributing to piston damage. 11 November 2024 72-00-00 Initial Issue Page 25 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 27 As mentioned in the Installation Manual (IM), it is the responsibility of the aircraft manufacturer to carry out exhaust gas CO measurement to confirm that their installation and/ or use of non ROTAX parts does not have a detrimental effect on carburetor calibration and is within ROTAX ® ®...
Page 28 3.13.4) Maintenance requirements Perform correct maintenance for the specific climate according to the relevant Aircraft Mainte- nance Manual. 11 November 2024 72-00-00 Initial Issue Page 28 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 29 - Check the proper function of the instrumentation and their sensors according to the relevant Aircraft Maintenance Manual. Perform proper calibration of whole measurement chain. 11 November 2024 72-00-00 Initial Issue Page 29 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 30 • If installed, make sure that the fail safe system pushing the throttle to max power in case of actuation cable failure is functioning correctly. 11 November 2024 72-00-00 Initial Issue Page 30 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 31 MAP with the throttle lever. Refer also to the pilot operating handbook of the aircraft manufacturer for relevant power setting. 11 November 2024 72-00-00 Initial Issue Page 31 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 32 To decrease power, first reduce MAP with the throttle, and then decrease rpm with the propeller control. See also section 3.4.3). 3.16.4) Maintenance requirements None. 11 November 2024 72-00-00 Initial Issue Page 32 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 33 25% (e.g. from 6 to 4.5 bar (87 psi to 65 psi)) but should also consider differences between cylinders. 11 November 2024 72-00-00 Initial Issue Page 33 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 34 Cylinder "B" with "Green" piston: CY01 0.002 mm 0.026 mm 0.130 mm 0.077 mm /PI01 0.0001 in 0.0010 in 0.0051 in 0.0031 in 11 November 2024 72-00-00 Initial Issue Page 34 of 35 Copyright - BRP-Rotax GmbH & Co KG. All rights reserved.
Page 35 ® In any case the original text in English language and the metric units are authoritative. 5) Inquiries Inquiries regarding this Service Bulletin should be sent to the ROTAX Authorized Distributor of ® your area. A list of all ROTAX Authorized Distributors or their independent Service Centers is provided on ®...

This manual is also suitable for:

912 s series 912 uls series 912 i series 915 i series 914 series 912 a series ... Show all