Fuel Selector Valve

[8474]

Not to get repetitive, but, you cannot (legally) install a valve that allows feeding from both tanks simultaneously unless the air spaces of those tanks are connected.

Also, the L-R-Both-Off valve actually connects the left and right tanks together when in the off position, which allows fuel transfer between the tanks.

Which may or may not be a good thing. If you are filling one tank then as long as you are patient it should fill both sides. The down side is that if you park on a slope with one wing down you could have an overflow. My brothers Airtractor has this issue.

[6643]

If you land with 3/8 on one side and the other side nearly empty, and your tanks equalize while you eat breakfast, you better be at a field with fuel available...

[6795]

Many different types of airplanes have many different types of fuel systems and I’m sure that there are many pilots who prefer one type of fuel system over another type. In my opinion, it makes no sense at all to modify a perfectly good fuel system that has a long history of successful performance based simply on pilot preference. In addition, there is a risk with this type of posting that someone reading it may believe that it is acceptable to modify their fuel system and install a fuel valve that could result in a life safety issue.

[8474]

And I agree, thats why I said this:

Not saying you should convert a LEFT-RIGHT system, but L-R-BOTH is the best of both worlds.