Primary finding
Probable cause
The pilot not maintaining clearance from the water during the survey flight. A factor was the low altitude the survey flight was flown at.
Investigator assessment
Analysis narrative
The experimental research and developmental helicopter's left boom impacted water during an offshore low level survey flight. The pilot's accident report stated, "While flying an easterly course line at approximately 25 knots over calm surface conditions, a course correction to the left was initiated with 2 degrees of left bank angle. This resulted in the left boom tip touching the surface of the water. The nose of the helicopter pitched down causing the main rotor blades to strike the water. The helicopter became inverted, sinking immediately. The elapsed time between the boom tip contacting the water and the helicopter becoming inverted was approximately three seconds." The pilot reported no mechanical malfunctions in reference to the survey flight.
Source record
Factual narrative
The experimental research and developmental helicopter's left boom impacted water during an offshore low level survey flight. The pilot's accident report stated, "While flying an Easterly course line at approximately 25 knots over calm surface conditions, a course correction to the left was initiated with 2 degrees of left bank angle. This resulted in the left boom tip touching the surface of the water. The nose of the helicopter pitched down causing the main rotor blades to strike the water. The helicopter became inverted, sinking immediately. The elapsed time between the boom tip contacting the water and the helicopter becoming inverted was approximately three seconds." The pilot reported no mechanical malfunctions in reference to the survey flight.