HONOLULU — The National Transportation Safety Board expects to release next week a probable cause for a 2011 Molokai helicopter crash that killed all five people aboard.
Pilot Nathan Cline, newlyweds Michael and Nicole Abel of Pittsburgh and Canadian couple Stuart Robertson and Eva Birgitta Wannersjo of Toronto died when the Blue Hawaiian Helicopters Eurocopter EC-130 crashed into mountains above an elementary school and burned. They were on a 45-minute sightseeing tour of West Maui and Molokai.
The agency’s statement on the probable cause is scheduled for next Friday, NTSB spokesman Peter Knudson said.
The agency released a factual report last week, indicating the investigation is in the final stages. The factual report is all the information that the NTSB will use to determine the probable cause of the accident.
According to the report, the engine was disassembled and examined, revealing “no evidence of mechanical malfunctions or failures that would have precluded normal operation.”
Investigators have focused on the tail section.
“According to Eurocopter, in addition to this accident, there have been four other accidents where the (tail rotor) separated from the tail boom at the junction frame during the accident sequence,” the report said.
Witnesses on the ground told investigators they heard a “woop wopping” sound, the report said.
“One witness observed the helicopter descending from the island’s central ridgeline; he reported that he observed pieces falling from the helicopter as it descended,” the report said. “Another witness, who was closest and had the clearest view of the accident helicopter, reported that the helicopter went ‘straight down’ and impacted the ground sideways. Other witnesses reported that they observed a large ‘fire ball’ when the helicopter impacted the ground.”
Blue Hawaiian Helicopters record sightseeing tours as a souvenir for passengers, but footage was not available to investigators, the report said, because the camera recording system was not meant to be crash-resistant.
A lawsuit filed by the family of a passenger against Blue Hawaiian was settled in March for an undisclosed amount, the Maui News reported.