document: They reveal that a few minutes before the plane went down, the pilots asked to move a few nautical miles north of their flight path because of weather conditions.
  The Dutch Safety Board says its preliminary report was based on the contents of the flight and cockpit data recorders, other communication with the plane, as well as forensic examination of the wreckage where possible.
  These are its key findings.
summary: Dutch investigators say the damage to Malaysia Airlines flight MH17, which crashed in eastern Ukraine on 17 July, suggests it was pierced by a large number of objects from outside the plane.