Sen. Al Franken is calling for an expedited investigation into how an airliner overflew the Minneapolis St. Paul International airport earlier this week.Flight 1888 stopped responding to air traffic control for 75 minutes and overshot its destination by 150 miles.Franken wants to know whether the industry's so-called 'sterile cockpit rule' may have played a part by discouraging the flight crew from communicating with the pilots.He also thinks the rule may have contribnuted to an incident back in August where a plane was stranded on the tarmac in Rochester overnight.