GREENSBURG, Ind. (AP) _ A preliminary federal report into a southeastern Indiana plane crash that killed two couples says investigators found no mechanical problems with the aircraft.
 
  But the National Transportation Safety Board’s report says witnesses told investigators pilot-activated runway lights were not illuminated when the small plane crashed Dec. 2 near the Greensburg Municipal Airport. The report says those lights were checked after the crash during foggy, misty conditions and were found to be working properly.
 
  Pilot Donald Horan, his wife, Barbara, and their friends Stephen and Denise Butz were killed in the crash as they returned from Destin, Fla.
 
  The report also says a pilot traveling a similar flight path a half-hour ahead of the doomed aircraft diverted away from Greensburg’s airport due to foggy conditions and landed safely at another airport.