Background and Flight History
On November 15, 2016, at about 1841 Hawaii standard time, a Hughes (MDHI) 369D helicopter, registration N81GG, impacted mountainous tree-covered terrain approximately 1 mile north of Pukoo, Hawaii. The airline transport pilot and a passenger were fatally injured, and the helicopter was destroyed by impact forces and a postcrash fire. The helicopter was registered to the pilot, who was operating it under Title 14 Code of Federal Regulations Part 91 as a personal flight. No flight plan was filed, and night instrument meteorological conditions prevailed at the accident site.
The flight departed from Daniel K. Inouye International Airport (HNL), Honolulu, Hawaii, at 1756, destined for a private residence near Pukoo on the island of Molokai. According to the pilot's mechanic, who helped load and fuel the helicopter, the purpose was to transport the pilot's friend from HNL to Molokai. The pilot lived and worked in Honolulu and had another residence on the east side of Molokai, which included a private helipad. The flight distance was about 65 nautical miles, with an expected flight time of 30 minutes.
Preflight and Weather
The mechanic reported that he advised the pilot not to fly given the weather conditions, but the pilot insisted because he had to tend to business. About 1730, the mechanic sent a text message to the property caretaker of the pilot's home on Molokai to check the weather. The caretaker replied, "mountain is a little wet and the clouds are low out East near the house," but the pilot had already departed.
Archived FAA voice communications from Molokai air traffic control tower indicated that at 1823, the pilot reported "2 miles southwest of the mudflats 1 mile off shore at 700 feet transition to the east." The control tower approved the transition through class D airspace and provided an altimeter setting of 3003. This last reported position was about 20 miles from the destination.
The National Weather Service area forecast, issued at 1734 and valid at the accident time, indicated scattered clouds at 2,500 ft and scattered to broken ceilings at 5,000 ft, with temporary conditions of broken ceilings at 2,500 ft and visibility between 3 and 5 miles with rain showers. AIRMET Sierra, issued at 1731, advised of mountain obscuration on the north- through east-facing slopes of Molokai due to clouds and rain.
The closest official weather station, at Molokai Airport (MKK) about 17 miles west, recorded at 1854: wind from 030° at 15 knots gusting to 21 knots, visibility 10 miles, broken ceiling at 4,800 ft, temperature 24°C, dew point 21°C, altimeter 30.04 inches of mercury. Archived radar data showed a line of rain showers moving from east to west over the accident site between 1834 and 1845. The pilot did not request an official weather briefing. Sunset occurred at 1746, with the end of civil twilight at 1809; the moon was not visible during the flight.
Witness Accounts
The Maui County Police Department interviewed six ground witnesses who observed the helicopter flying overhead in the Pukoo vicinity on the night of the accident. They stated that the weather conditions were dark with rain and wind, and the helicopter had its searchlight on. One witness, who lived 1.2 miles southwest of the helipad, saw the helicopter fly from the coastline to the mountain ridge and perform an approach toward the pilot's helipad but lost sight when it entered a cloud.
The NTSB interviewed four ground witnesses. One witness, who lived about 1 mile southwest of the helipad and 2 miles from the accident site, observed the helicopter flying "surprisingly low" and slow with its searchlight on. She recognized the pilot's helicopter and stated that the pilot had flown in "horrific conditions" before. She reported that it was "very dark" and "very windy" with clouds and rain higher up on the mountain. An iPhone photograph time-stamped at 1836 showed the helicopter flying in dark night conditions.
Another witness, who lived 0.2 mile east of the pilot's property, stated the weather was "very windy and rainy" and "as bad as I've ever seen." She observed the helicopter perform a controlled approach to the ridgeline above her house, not the ridgeline to the west where the pilot's helipad was located, and then descended behind terrain and disappeared. She observed a bright orange illumination in the clouds sometime after.
Pilot and Aircraft Information
The pilot, age 70, held an airline transport pilot certificate with a rotorcraft-helicopter rating issued on December 29, 2009. He also held commercial and private pilot certificates for airplanes. His most recent FAA third-class medical certificate was issued on May 17, 2016, with a limitation to have available glasses for near vision. On his medical application, he reported 4,210.7 hours of total flight experience, with 45.2 hours in the last 6 months. His logbook was not located, so instrument and night experience could not be determined.
The helicopter, serial number 100634D, was manufactured in 1979 as a Hughes 369D. It was powered by a Rolls-Royce (Allison) 250-C20B turboshaft engine and was controlled by a single pilot from the left seat. The last annual inspection occurred on September 17, 2016. Airframe total time was 9,640.1 hours, and engine total time was 8,371.1 hours. An emergency locator transmitter was not installed or required.
Wreckage and Impact
The accident site was on the southeast side of Kamakou Mountain, on a 25° southeast slope at 1,389 ft elevation, about 0.75 mile north of the helipad. The wreckage field was about 80 ft long and 25 ft wide, with burned and fragmented components on a heading of about 310°. Postimpact fire damage was extensive. Tree strikes indicated a descent angle of about 18°. The landing skid tubes separated; the left skid was imbedded almost 30 inches into the dirt, consistent with forward flight and the initial impact point.
The altimeter indicated 913 ft with a setting of 30.00 inches of mercury. The dual tachometer showed an NR reading of 340 rpm and N2 reading of 78 percent. The pilot's watch had stopped at 1841. The GPS unit was not located. The engine exhibited significant thermal damage; no mechanical anomalies were found that would have precluded normal operation.
Helipad and Lighting
The private helipad was upslope of the pilot's residence at about 750 ft on a ridgeline. It had four red A650 automatic solar-powered perimeter lights on 14-inch mounting pads and four red vertical exterior lights attached to an 18-foot ladder on the hangar facility. The vertical lights were controlled by a mechanical pin timer set from 2000 to 0600. The property caretaker reported that the lights should have been on the night of the accident, but it is unknown if they were illuminated. Red lights were also installed on the perimeter of the roof of the pilot's residence to assist with navigation.
Medical and Pathological Findings
An autopsy determined the pilot's cause of death as undetermined with probable multiple blunt force injuries. Toxicological testing was negative for ethanol and drugs.
Cyclic Grip Examination
The pilot's cyclic grip, one of the few flight control sections that survived the fire, was examined using x-ray and CT scanning. The scans revealed multiple cracks, displaced trigger switch interior mechanisms, splayed core electrical wire strands, and a nose-down trim wire that appeared close to the trim switch ground contact solder. Disassembly showed that four of five soldered connections exhibited varying levels of disbonding, with the fifth completely disbonded. These findings were consistent with wires separating under tension during impact.
Search and Discovery
After the helicopter's expected arrival time, the mechanic was unable to contact the pilot. The next morning, the caretaker checked the residence but found no sign of the pilot or helicopter. The US Coast Guard and Maui County Police Department conducted a search. At 0852, the FAA issued an alert notice. Maui fire and rescue helicopter crew discovered the wreckage at about 1331 in Pukoo.