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912 Versioning question...

  • Faisal Asif
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4 months 1 week ago - 4 months 1 week ago #17220 by Faisal Asif
Faisal Asif created the topic: 912 Versioning question...
Respected Rob,

I need your assistance to clarify a few things.

About 4 months back I wrote a query. Quoted Below for reference:

We bought a Rotax 912 ULS engine from UAE Dealer on 30 Jan 2010 with serial number # 6775891 which went into a crash (the crash had nothing to do with the engine, it was working perfectly fine.) As we are the manufacturers of the aircraft, we are now working with the government agencies for the followup investigations. We want to know if the engine serial number # 6775891 was a ULS or ULS2 or ULS3 , It seems we have a conflicting set of documents to claim ULS3 and ULS2 status!

Thank you in advance.

to this you replied the following:

6775891 was manufactured as a 912ULS2.
It is easy to convert it to a S3, maybe this is what happened.

to this we requested the following:

Thank You Rob for your quick reply.
Can you please highlight the steps it takes to convert ULS2 to ULS3?

Your answer was:

here is a sample of the certification statement:
Engine modified from propeller version S2 (fixed pitch) to version S3 (hydraulic governor drive)
Work performed as per Rotax 912/914 Heavy Maintenance Manual Edition 1 Rev 5.
Chapter 72-00-00 Section 3.9.1, 3.9.4, 3.9.5 for modification. Section 3.9.8 & 3.9.13 - 3.9.16 inclusive for reassembly.
• Removed version -2 propshaft p/n 837285, s/n xxxxxxx & replaced with -3 propshaft p/n 837284, s/n xxxxxxxx.
• Installed governor drive parts for hydraulic governor.
• Marked gearbox with new part number 877708 to reflect change to version 3.
• Friction torque set to xxx inch lbs.
• Marked engine dataplate as 912S 3.

The complication in issue is, all of my documentation says that it was a ULS3 engine whereas there was no hydraulic governor installed on it, yes there was space and a blank blocking the hydraulic governor installation site:

1. Is it possible to use the ULS3 engine with above mentioned modifications with a fixed pitch propeller if the hydraulic governor is not installed?
2. Will the engine behave the same as ULS2 without the hydraulic governor installed?
3. Will there by a weight difference when converting ULS2 to ULS3 without installing the hydraulic governor?

I would remain in debt for you time that you take to help me clear out this mess!


Last Edit: 4 months 1 week ago by RotaxOwner Admin.

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4 months 1 week ago #17221 by Rob Seaton
Rob Seaton replied the topic: 912 Versioning question...
I do not know if this makes your mess better or worse:
1. Yes. If you modify a S3 by plugging the propshaft (sealing plug part number 244980) and removing the governor the engine is now a S4.
2. Yes
3. Yes but it is probably negligible for the W&B.
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