Accident Overview
On September 2, 2016, about 0945 Hawaii-Aleutian standard time, a McDonnell Douglas 500N helicopter, registration N5232G, was involved in an accident near Honolulu, Hawaii. The helicopter was being operated as a public aircraft for a rescue mission. The pilot, one crewmember, and a passenger were not injured; one crewmember sustained serious injuries. The helicopter was not damaged.
Sequence of Events
The pilot reported that after being dispatched to assist a hiker in distress, he took off from the airport and flew toward the hiking trail lookout, where fire department personnel were already present. He flew over the lookout and surveyed the area, observing a utility pole on the east side. The pilot estimated the wind was about 10-20 knots from the east. He landed the helicopter in a nearby landing zone and prepared for a rescue net extraction.
After taking off and flying to the injured hiker, the long line was extended to about 75-100 ft, and the injured hiker and a firefighter climbed into the net. As the helicopter started to ascend, a strong gust of wind unexpectedly caused the helicopter to ascend too quickly and move laterally toward the utility pole. The pilot attempted to stop the swing of the long line, but the net impacted the utility pole. The firefighter was electrocuted and fell from the net about 20 ft to the ground.
Weather Conditions
At the time of the accident, the Hawaiian Islands were under the influence of tropical easterly winds and under a Hurricane Watch. Surface observations indicated northeast winds of 14-20 knots with peak gusts of 28 knots during the period surrounding the accident. The northeast winds would produce downslope conditions and unfavorable conditions in the Diamond Head area. The National Weather Service had issued an AIRMET for moderate turbulence below 10,000 ft to the lee of higher terrain due to stronger winds. The closest upper air sounding taken in the hour indicated little change in wind direction with height and wind speeds of 30 knots immediately above the surface.
Operational Guidelines
The operator's "Technical Rescue Standard Operating Guidelines" state: "Team members and the pilot shall agree that the area they are being inserted into is safe and free of obstructions."