Bill: The wing tanks are interconnected and for all practical purposes can be treated as one tank. If you fill ones side and the other is empty, you will soon have 2 half full tanks.
There are a number of potential causes of problems. If the vent systems are out of sync between the two tanks that can force fuel to the tank with the lower pressure. This can be due to faulty fuel caps or cap gaskets. Excess fuel draining back from the header tank can overwhelm the capacity of the tanks to self equalize, causing the tank closest to the return to overflow. This is usually due to a missing flow restrictor in the pump outlet. Simply overfilling the system can cause the same problems, too. The correct procedure is to fill the header tank first, and only if fuel in the header was used due to exhaustion of the wing tanks, otherwise it should be at the correct level. Over filling the header will cause fuel to drain back to the wings automatically. Next, fill each wing tank to within 1" of the top. Any more than that and they may overflow even if things are operating correctly. John Cooper Skyport Services 4996 Delaware Tnpk Rensselaerville, NY 12147 518 797-3064 www.skyportservices.net
