New SB related to various engine issues

I am curious why at the top of this Service Bulletin it says "Mandatory". If its mandatory, shouldn't it be an ASB instead of just a SB?

Here's a question - How many have the necessary equipment to do everything on that SB?  Back pressure etc?  And are they expecting people to open the engine to confirm pistons?

Seems like a backside covering exercise in my humble opinion!

Hi John and all

The reason for the bulletin is the failure of many OEM, both full aircraft companies and kit builders, do not follow the installation requirements.  When you by an aircraft,  or aircraft kit, you should expect that the OEM did the testing on the first prototype model.  Unfortunately that is not the case for many I have found.  

The biggest reasons for piston failure is normally bad fuel and bad operation.  Overpitch on the props and low octane fuels mostly.  There are other reasons however, such as small restrictive mufflers, especially on the 912S and ULS 100 HP engines.  Many companies use their own design mufflers and try to reuse them for every application and model.  I can tell you from experience the mufflers from an 80 HP engine normally are way too restrictive for the 100 HP, the result can be detonation.  In-flight adjustable props not set correctly are another major problem.  The information is very clear on the correct setting methods and must be followed.  

It is a massive read however it is needed as far too many are not doing the due diligence to verify the correct installation from the start.  

Cheers

Thanks for the response - But it doesn't answer the question.

So the question I have is as follows;

I have a machine that is now over 500 hours in.  I gather I only need to pay attention to the items that state -Operator requirements?

OEM - is for aircraft manufacturers installing new engines.

Would that be correct?

Without wishing to preempt a more informed response from RW, my suggestion is;

Read the SB. Take from it what you think applies to your engine/installation/operating procedures.

If you find something like Exhaust Back Pressure test, to be beyond your understanding/ability to act on (lack of appropriate training/equipment /etc) discuss with LAME (Rotax) and or get back on the Forum with a specific enquiry eg "My aircraft is a ??? Rotax 912ULS, fitted with Rotax exhaust system/Factory system - do you think I should investigate the exhaust back pressure?"😈