The collision of two NWA planes last year at Minneapolis/St. Paul International is still under investigation so NWA and the NTSB wouldn't comment for this story. In fact, investigators didn't want us to get our hands on the tape until now. Experts who have viewed the tape wonder why the planes didn't explode on impact. May 10, 2005, an airport security camera is rolling as Northwest flight 1849 pushes back from the gate. Onboard 38 passengers, five crew members and thousands of gallons of fuel for the flight to San Antonio. At the same time, another Northwest plane is just...