The National Transportation Safety Board today released its final report on the crash of a Piper Saratoga II aircraft last summer that killed the pilot, John F. Kennedy, Jr.; his wife, Carolyn Bessette Kennedy; and her sister, Lauren Bessette. The airplane crashed about 9:41 p.m., on July 16, 1999, near Martha's Vineyard, Massachusetts.
The probable cause of the accident, as stated in the accident report, is:
"The pilot's failure to maintain control of the airplane during a descent over water at night, which was a result of spatial disorientation. Factors in the accident were haze and the dark night."
The accident report may be accessed through the aviation synopses page on the NTSB website.. The NTSB accident number is NYC99MA178.