The National Transportation Safety Board is unable to determine why a helicopter crashed in a St. Paul suburb last June, killing the pilot.
Michael Kramer of St. Charles was spraying for mosquitoes in the area when the helicopter he was flying crashed into the backyard of a Maplewood home. Kramer was alone in the helicopter.
In its final report, the NTSB indicated the helicopter appeared to be working fine when the crash happened. Winds were light at the time.
Investigators retrieved a GPS which tracked the final flight and found nothing to indicate the helicopter had experienced a problem.
The helicopter had taken off from Flying Cloud Airport in Eden Prairie and was spraying near 3M Lake at the time of the crash.