The National Transportation Safety Board is close to completing its investigation into a 2011 helicopter crash on Molokai that killed four passengers and the pilot, according to its website.
Last week, the agency released updated details of the crash, including background information on the pilot, an engine report and an audio and video recording from other air tour helicopters that were flying nearby at the time of the accident.
Nathan Cline, a 30-year-old pilot with 4,500 hours of helicopter flight time, arrived for work at Blue Hawaiian Helicopters at Kahului Airport on the morning of Nov. 10, 2011, at about 7:30 a.m., his typical arrival time according to other company pilots. He had been hired only four months prior and had 306 flight hours with the company's Eurocopter EC130 B4 helicopters.
The National Transportation Safety Board recently released a factual report on a Blue Hawaiian Helicopters crash on Nov. 10, 2011, near Pukoo, Molokai, that killed the pilot and four passengers. The agency is close to completing its investigation of the crash.
National Transportation Safety Board photo
After checking the weather that morning, he completed a preflight inspection on the assigned helicopter and then waited for his first passengers of the day to arrive, the report said. He had passed an airman competency check ride, administered by a Federal Aviation Administration inspector, just one day prior.
Cline completed two sightseeing tours that morning without incident. He departed from Kahului Airport around 11:44 a.m. for his third tour of the day, with a honeymooning couple from Pittsburgh and another couple from Toronto.
The round-trip flight was scheduled to take one hour and 10 minutes, but at approximately 12:14 p.m., the Eurocopter helicopter struck mountains near Pukoo on Molokai's East End.
Winds were gusting to 31 mph in the moments leading up to the accident, according to weather reports gathered from Molokai Airport, located about 15 miles west-northwest of the accident site. Visibility was limited to 8 miles, with scattered clouds at 2,600 feet. An advisory had been in effect at the time, warning of a surface wind from the east-northeast of 29 mph to 35 mph over mountain ridges and through valleys.
On-ground witnesses reported that the accident occurred during or in-between heavy rain squalls and described the weather conditions as "poor."
The planned route of the flight was to fly north-northwest from Kahului Airport to the northern tip of Maui before proceeding northwesterly toward the northeastern shore of Molokai to view the Halawa Valley and Papalua waterfalls, the report said. If weather permitted, the flight was to continue west into Wailau Valley and to climb up and over the valley to the southern side of Molokai. If weather conditions would not allow the pilot to use the Wailau Valley route, an alternate route was to reverse course and fly back eastbound along the northern shoreline and then proceed around the eastern tip of the island to the south side.
Although pilots described weather conditions as not permissible for the Wailau Valley route, the last pilot to see Cline's helicopter reported seeing it flying westbound above the mountainous terrain on the southern side of Molokai, just below the cloud ceiling (about 2,000 feet in elevation). The witness, a helicopter pilot flying for Air Maui, said Cline appeared to be in straight and level flight and not in any form of distress.
But shortly after, witnesses on the ground reported hearing a sort of "woop wooping" sound. One witness reported seeing pieces falling from the helicopter as it descended. Another witness, who was closest and had the clearest view of the helicopter, reported that the chopper went "straight down" and impacted the ground sideways. Another witness reported seeing a large "fire ball" when the helicopter impacted mountainous terrain about 5 miles west of Pukoo.
The overall wreckage debris field measured about 1,330 feet in length and was located in a remote area that made it difficult for firefighters to reach and to extinguish the post-impact fire.
The pilot was not in radio contact with air traffic control, and no distress calls were heard by other pilots during the time of the accident, the report said. An autopsy revealed that there were no signs of drugs or alcohol in the pilot's system.
The NTSB has not published its findings on the cause of the crash, but the report released last week included an engine examination report.
The engine from the helicopter was disassembled and examined and revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Aviation experts also examined the Fenestron (tail rotor), tail boom and horizontal stabilizer.
Manufacturers of the Eurocopter told NTSB officials that the tail boom and Fenestron have experienced failures in at least four other accidents, during which the Fenestron separated from the tail boom at the junction frame during an accident. Pieces of the Fenestron were found scattered in multiple areas in and around the crash site at Pukoo.
Killed in the crash were Cline; honeymooners and Pittsburgh residents Michael Todd Abel, 25, and Nicole Bevilacqua-Abel, 28, who both worked as engineers at Westinghouse Electric Co.; and Toronto couple Stuart Robertson, 50, and Eva Birgitta Wannersjo, 47.
Cline's widow, Violeta Escobar, filed a federal lawsuit last year against the helicopter's manufacturer European Aeronautic Defense and Space Co. and Nevada Helicopter Leasing, which owned the helicopter. She claims in the lawsuit that the companies should have known of manufacturing defects that could cause the helicopter's structure and components to fail without warning. The suit is still pending.
Another lawsuit filed by the family of another passenger against Blue Hawaiian was settled in March for an undisclosed amount.
A representative of Blue Hawaiian Helicopters did not immediately return a call for comment on Thursday.
* Eileen Chao can be reached at firstname.lastname@example.org.