Emptying the -12 Fuel Tank

For those thatr have done this do you have any suggestion for the best way to remove the fuel from the tank before removing the tank from the plane.
Thanks in Advance

I remove the hose from the fuel pump on the nose of the Rotax, attach a fitting to the hose with a piece of aluminum tubing on it, and use the electric fuel pump to pump the fuel into a gas can. This will get a majority of fuel out. I then put an oil change tub under the opening in the bottom of the fuselage where the fuel fitting into the bottom of the tank is located. Reach up and remove the fitting (and be prepared to get drenched in some residual fuel).

It may not be the best way, but it works and is fairly quick.

On my RV-12, I disconnect the outflow fuel line at the gascolator and install a temporary fitting with a short aluminum tube that feeds into a fuel storage container placed below the gascolator. Intermittently use the electric fuel pump to empty the tank - take your time. Be patient with the emptying process as the electric fuel pump can empty the tank's internal reservoir faster than the fuel can refill the reservoir. You can tell when the electric fuel pump is just pumping air by the change in its sound. Repeat the process until no more fuel flows out. As Randy noted above, there will be some residual fuel in the tank when you unfasten the two tank bottom fittings - be prepared!

Be sure to take all appropriate safety precautions (e.g., bonding/grounding, fire extinguisher nearby, out of the hangar, etc.). Of course, it also helps to fly the plane before the draining to reduce the amount of fuel you have to drain.

There is a lot of discussion regarding this in past posts - try a SEARCH.

I follow David's procedure and would agree, be patient. It usually takes at least 3 finish cycle of the fuel pump off, wait, and then again to pump more fuel, sound change-air, off. Wait and repeat like I mentioned at least 3 cycles towards the end. And there will be some fuel left over, but not too much

The procedure detailed in the RV-12 Maintenance Manual (beginning on page 13-4) works quite well. It even includes steps that reduce the fuel mess when disconnecting the lines on the bottom of the tank, to almost zero.

The most recent release (April 2014) can be viewed HERE

I do not like the idea of taking the fuel system plumbing apart to drain the tank. While I had the tank open for the vent modification I added an AN832-6D on the top-right aft corner with a 3/8 pipe to the larger volume side, bottom corner of the lateral baffel. Defueling is realtively painless; remove the AN929-6D cap, connect an external electric fuel transfer pump (recycled F-150 electric FP) with an AN fitting on the suction side, turn it on and in a few minutes it will be empty. The little residual fuel empties with the drain/sample valve.

An additional benefit is the ability to connect an Aux tank if I ever need one.

John Salak
RV-12 #120116
N896HS

Maintenance manual

This may be a little off topic. It it better to have the newest version of the Maintenance Manual or the Manual that was current when our aircraft was built? I have an early build and there have been some changes since ours was finished.

Rich