Thank you Sonny--APU question is satisfied.--What I was getting at relating to one tank suction feeding both engines was : Will both engines be capable of continuous operation receiving fuel from one tank(suction feeding),with all pumps off. Since my original post, I have gone back, looked at the flow chart, and have concluded:"With all pumps off, crossfeed open, both tanks will probably balance out". It is now apparent that there is no outlet valve to isolate a single tank. Does this sound correct??. thanks ahead of any reply---