Rotax 914 applicable ADs

Hi Trevor

First, only certified aircraft have ADs and they only apply to what is in found in those aircraft.  The extent of that is found on the respective authorities pages like the FAA.  Only the FAA can issue an AD and it applies to aircraft that hold a full TC.  That said I assume you want to know the Rotax version of an AD?

Rotax will issue an ASB, alert service bulletin, if it is a safety of flight issue.  This exists for both the certified version and the experimental version model of that engine.  In the case of the type 914 certified is a 914F and the experimental is a 914UL.  We need to watch this since the serial range is completely different.  There are several websites that allow a serial check by engine model, Rotax-owner and FlyRotax both do but be sure you are under the correct engine type.  You can not just plug in a serial and have a make model pop-up.  

If your engine is in an SLSA or ESLA in the USA there are some different rules.  The listed manufacturer is the OEM (or his importer) who signed the compliance statement for the FAA 8130-15.  That said the regulations are that the listed OEM must issue a "safety directive" that would have the same force as an AD in the certified world.  Be careful here because there are many Rotax "Mandatory" bulletins that are not directly safety of flight and while you should follow them technically they are not an AD or a Safety Directive unless the FAA or the OEM (LSA) has listed them.  

So the good bit is if you are flying as an experimental just follow the listed bulletins, no problem.  If you feel it is a safety issue go after your importer.  I would even shame them and ask why a safety issue is not addressed by them.   Just my view.

Cheers

This sounds good in theory, but when I search flyrotax.com for all ASBs affecting 914UL engines, I do not see either the circlip issue or the latest float replacement guidance, both of which are considered mandatory.

I agree with the original poster that Rotax does a very poor job of making it easy to determine what an owner should do. In fact, they seem to go out of their way to make it difficult. Speaking only about Rotax "headquarters" not about any Rotax affilliate.

"Alert Service Bulletins contain service requirements and instructions that are very important to flight safety and must be addressed, complied with, or accomplished before continued flight operations.  Alert Service Bulletins will always be superseded by a Service Bulletin.

Service Bulletins contain service requirements and instructions that must be addressed, complied with or completed within a specified period."

The circlip and carb-float bulletins are of the latter type.  

Thank you for the feedback Ken and Tyler, much appreciated. 

Any thoughts anyone on SB-914-011 for REPLACEMENT OF VALVE SPRING RETAINER ON SINGLE VALVE SPRING CONFIGURATION OF ROTAX® ENGINE TYPE 912 AND 914 (SERIES) ?

Upon reading this, it seems to be a replacement part as "insurance" against failing to purge the oil system properly as it says "This condition can occur, if the hydraulic valve tappet has been emptied and filled with air. This is possible at first engine run or at oil change"

It seems quite a lot of work for something that would not happen if you did the purge properly, including the tedious check of every hydraulic valve as described in the purge procedue - there is an excellent Rotax video which covers this purge procedue very well. 

Thoughts ?

Regards

Trevor

I would definitely do the replacement of the valve-spring retainers, if it applies to your engine and hasn't been done already (that is a 20yo SB, but it is a mandatory one).

In the past there have been issues with oil filters that allowed air into the system, so it wasn't always obvious when the system needed to be purged.  Air in those tappets over a certain period of time can (will) cause catastrophic engine failure.

FYI, one way to check if there is currently any air in there is to remove the valve covers and press down on the lower part of each rocker arm (use, say the handle end of a hammer and push/lean against the head end of the hammer).  If it's properly filled with oil, the rockers should not move (oil being incompressible).