YONKERS - According to an NTSB report, poor visibility and a possible medical condition may be some possible factors behind the small plane crash near Westchester County Airport that killed a member of the Rockefeller family.

As News 12 has previously reported, the plane crashed in a Harrison neighborhood minutes after takeoff, killing 65-year-old Richard Rockefeller, the great-grandson of Standard Oil co-founder John D. Rockefeller.

Experts say that while mechanical error can't be ruled out yet, all signs so far indicate that the cause of the crash was not a plane malfunction.

The report's findings indicate that the plane's engine was functional, and the aircraft had its full annual inspection a week and a half before the crash.

The NTSB investigation is now shifting to Oklahoma City, where it could take about a year for the agency to complete its full report.