Using auto fuel in training planes

What's the legality in using auto fuel for training aircraft. Is it ok as long as they have the auto fuel STC?

Yep it's fine as long as you have the STC, unless there is some stipulation within the STC limiting operations while using MOGAS.

Why would it NOT be ok in an aircraft that has the STC?

Ok thanks. When I did my multi and seaplane the guy had a truck with a 80 gallon tank on the back that had a pump just like a regular gas station would. When I got back we did a similar setup with a old pickup for our Cherokee. I was just thinking one way you could open a lower cost flight school was to have a fleet of planes that could run on autogas. They could be planes that have the STC or the new light sports that have the rotax engines that are approved for 91 octane mogas

A A&P told me once that auto fuel couldn't be used in a training fleet because it would go against the STC

Every STC I've seen has said the auto fuel can not contain alcohol. Otherwise I know of no restriction for training aircraft.

Auto gas can be used in anything that has an STC. Alcohol voids the STC. I ran a 172 Lyc about 2000 hours on a combo of auto gas and avgas about 20 years ago. Worked great. Biggest problem I had was airport management not being too keen on me having a 100 gal tank in the back of my pickup. YMMV

No monies for them...

I have been meaning to buy an STC for the 150. It'd be about a 25 hour return on investment for me not including the intangible costs of having to make a trip to the gas station and fill jerry cans.

The trick is finding a reliable source of auto fuel that doesn't contain alcohol, if it isn't sold on the airports you frequent and around here I'm not familiar with any airports that sell mogas.

Most auto stations do contain alcohol, which you cannot use in aircraft. The web site http://pure-gas.org can help locate stations that sell alcohol free gasoline. The alcohol restriction is important to obey, I have a close friend who's an A&P-IA who has had to clean up leaky gunky fuel systems where owners ignored the alcohol warning and it's made him very skeptical of the autogas STC'd aircraft.

The only operational restrictions I've heard of with auto gas STC's is in part 135 charter operations, I have not heard of any other restrictions on commercial activity.

I live in a boating town so just about every local gas station carries ethanol free gas under the name recreational fuel. Also a bunch the airports around here carry autogas on the field. One guy I know has a 1000 gallon tank at his gas strip at his house that he just calls a distributor and splits a ethanol free load with a gas station because they won't come for his 1000 gallon tank alone

That sucks they don't come for 1000 gals.

it's common. I think the cutoff is 2000. We have a 800 gallon avgas tank at glider airport and we have to wait till the airport down the street gets a delivery for us to get ours filled

The family farm has a 1000 gal tank and they come out and fill it every month.

lucky. Around here they wont send truck for less than 2000. At least not the ones I have talked to. I'd like to get a 500 gallon tank at the house for the Cherokee not sure how I would get it filled

Have you tried any of the ag places around there? I've heard they do the fuel like a milk run and fill up peoples tanks along their route.

Just curious, Is there any risk in swapping around mogas and avgas as far as the engine is concerned? Ex: Fill up with mogas at home go on XC fill up with pure avgas fly home then repeat on a regular basis.

No. Some A&P recommend throwing avgas in once in a while for the lubricating quality of the lead

Nope, no problem, in fact I've heard of a lot of guys who will keep one tank of 100LL when they first run auto fuel. They run the 100LL during takeoff and landing and switch to mogas in cruise, until they gain confidence in the mogas, then they usually just switch over completely.

Thanks