Interesting - the 52DB can switch the generator between tanks and the supply and return fuel are switched independently but the mains are dedicated to their own tank. I suppose the generator on the 52 could be used to transfer fuel from one tank to the other to obviate the need to switch the mains..... My 400DA, on the other hand, could switch the mains between tanks and switch the supplies and returns independently; however, the generator was dedicated to the starboard tank....That’s what I thought, can’t imagine why it was designed that way- thanks for the responses