Rotax mandating a fuel return line

[Anticept]

Rotax has changed their installation manual to mandate the use of a fuel return line in all 9 series engines. This change has been in effect for a while now, but this has no legal enforcement on S-LSAs, as it is the airframe manufacturer who dictates how it is to be designed, but I figured I would bring that to people's attention.

Essentially, fuel vaporization without a method of purging the lines continues to be an issue. Once upon a time, they found it preferred to have a return line, but acceptable to simply run it to the gascolator. Now they want return lines used, period.

A return line cannot just simply be run if you have more than one tank, especially if you have a fuel selector switch. Considerations must be made that you don't select one tank, and the return line fill another past limit.

 

 

[procharger]

So what does all this mean for CT owners?

[bmar]

Are we required to change this at annual? 

[Anticept]

As said, it has no regulatory backing. I brought it here as a point of discussion.

[procharger]

Are there any  problems as far as the CT design,  everything is wrapped

with insulation for the most part with fuel lines?

[Roger Lee]

This fuel restrictor is in all CT's. No action required. It has been a standard with Rotax for almost 20 years, but they finally changed the language in the manual. Back in the earlier days with the 912 most engines were open air engine mounts. Now days they are in a tight cowl which helps retain a lot of heat.