Everything is ready (from the use in aerospace industry as an indication that all preparations have been made to launch)
All systems go. We leave in 5 minutes.
by The Return of Light Joker April 22, 2011
1 more definition
when one is defecating and feels the urge to urinate in consequence
dude i was taking a huge dukie and i felt the need to let all systems go
by JLOBSTER January 23, 2011