Hi Microburst2002 & vilas,
Since the suction valve is in the same part of the fuel tank as the main fuel pumps, please explain the scientific physical reason why you think the suction valve would uncover when the crossfeed valve is open and the aircraft has 3 degs of side slip.
See "Suction Valves" DSC-28-10-Engine Feed, General, Main Components.
(N.B. The main fuel pumps don't uncover with full side slip deflection.)
