CEN18FA074

A loss of engine power due to snow or ice ingestion at an altitude that was insufficient to allow for engine re-ignition. Contributing to the accident were conditions, including altitude and flat light conditions, that precluded a successful autorotation to the field.

The commercial pilot and the crewmember departed on a power line aerial observation flight. Security video showed the helicopter sat on the ramp, in falling snow, for over an hour before departing for the accident flight. While two people were seen in the video walking around the helicopter before the flight, the distance was too great to ascertain how much snow or ice may have accumulated in the engine inlet area or what, if any, preflight snow or ice removal actions were taken by either the pilot or the crewmember. One witness in the area observed the helicopter descend at an angle before it impacted the ground. Recovered GPS data indicated that the helicopter was operating in right turns consistent with the slow, hover flight (line inspection operations) with at an altitude between 180 ft and 220 ft agl and an airspeed of less than 10 knots. Satellite, radar, and weather observations near the accident site supported low clouds and visibility with light to moderate snow fall at the time of the accident. Weather models and advisories support the probability of structural icing in the area at the time of the accident. In addition, witnesses described the snowfall as moderate at the time of departure from the airport and at the time of the accident. Photographs taken by law enforcement following the accident further illustrate falling snow and flat light and or white out conditions at the time of the accident. Ground scars and damage to the helicopter were consistent with the helicopter impacting the ground in a vertical and level pitch attitude. Further, the damage to the main rotor hub and main rotor blades was consistent with excessive coning and downward flapping of the main rotor blades. These characteristics are consistent with a loss of engine power or thrust on the main rotor system. The RE-IGN bulb stretch signatures are consistent with activation of the engine ignition system, indicating that power turbine speed was low. The lack of stretch signatures on the flashing engine out caution panel light is likely due to the light's cycle stage at the time of the impact. There were no mechanical anomalies with the helicopter, engine, or fuel system that would have precluded normal operations. There was no damage to the compressor, compressor front support vanes, or first-stages rotor blades that was consistent with hard body ingestion. Investigators were not able to determine how much snow or ice accumulated on the helicopter while it sat on the ramp or how much snow or ice was removed before the helicopter departed. The helicopter was operating at a slow forward airspeed and in hover for most of the flight increasing the likelihood of snow and or ice accumulation in the engine inlet area during the hover inspection operations. According to the engine manufacturer, snow ingestion cannot be ruled out as it does not always produce visible damage to the compressor. The helicopter was not equipped to prevent or mitigate the accumulation of snow in the inlet; only to prevent snow and ice from entering the engine through the fuel system. The manufacturer required the installation of the auto-reignition system in order to operate in snow and ice; however, the low altitude where the loss of engine power occurred was likely insufficient for a successful auto-relight and recovery of engine power. Performance charts indicate the helicopter was operating within an airspeed and altitude combination which would make a successful autorotation difficult to perform. The flat light and/or white out conditions would increase the difficulty of judging altitude, depth, and distance during an autorotation.

The Lucas County Coroner's Office, Toledo, Ohio, performed the autopsy on the pilot on January 16, 2018. The autopsy concluded that the cause of death was "multiple blunt force trauma" and the report listed the specific injuries. The FAA Forensic Sciences Laboratory, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the pilot's autopsy. Results were negative for all tests conducted. A weather study was conducted by the National Transportation Safety Board (NTSB) in support of this accident investigation and the detailed weather study is available in the public docket. The National Weather Service (NWS) Surface Analysis Chart for 1000 local depicted a low-pressure system located over southern Wisconsin with its associated frontal boundary stretching northward into Canada and southward into Illinois, Indiana, and Missouri. A high-pressure system was located over central Virginia. The accident site was located in between the high- and low-pressure systems. The station models around the accident site depicted air temperatures in the mid to high teens (Fahrenheit (F)), dew point temperatures in the low teens, with temperature-dew point spreads of 5° F or less, an east-southeast wind of 5 to 10 knots, overcast sky cover, and light snow. The Geostationary Operational Environmental Satellite-16 depicted abundant cloud cover above the accident site at the time of the accident, with that cloud cover moving from southwest to northeast. Infrared imagery indicated cloud tops at 13,000 ft msl. There was a meteorological impact statement valid for the accident site at the time of the accident for areas of marginal visual flight rules and instrument flight rules with light snow spreading from west to east in addition to light to patchy moderate ice between 1,500 ft and 10,000 ft msl spreading from west to east. There were Airmen's Meteorological Information (AIRMET) Sierra and Zulu valid for the accident site at the accident time for IFR conditions due to precipitation and mist and moderate icing conditions below 15,000 ft msl. A search of official weather briefing sources, such as contract Automated Flight Service Station (AFSS) provider Leidos weather briefings and the Direct User Access Terminal Service (DUATS), was done and the accident pilot did not request a weather briefing through Leidos or DUATS. A search of archived ForeFlight information indicated that ForeFlight did not have any record of the accident pilot requesting a weather briefing before or during the accident flight. ForeFlight did record that the accident pilot accessed the Central Great Lakes NOAA Doppler radar loop weather Imagery at 0958:07. With no internet access while in flight, ForeFlight is still able to access weather information directly from the FAA but leaves no remote record of such access. It is unknown if the accident pilot checked or received additional weather information before or during the accident flight. The weather conditions at 1G0 were visible in the security camera video. The visibility was reduced, and it was snowing. Witnesses at the airport characterized the weather at 1 ¼ to 1 ½ miles visibility, with moderate snow, and unknown ceilings. Photographs taken by law enforcement following the accident further illustrate falling snow and flat light and or white out conditions at the time of the accident. The general manager of the Bowling Green Flight Center reported that it was snowing when the accident helicopter arrived at the 1G0 fuel pump area around 0920. It was still snowing when the accident flight departed around 1024 with 1 to 1 ½ miles visibility. The flight support manager recalled 1 ¼ miles visibility and the accident helicopter departed into instrument meteorological conditions with moderate snow. The Current Icing Potential (CIP) product created by the National Weather Service and valid for the accident site indicated between a 20% to 50% probability of icing at 1,000 ft and 2,000 ft at 1200 at the accident site. The CIP indicated that the icing near the accident site would likely be trace to moderate intensity. The CIP also indicated an unknown chance of supercooled large droplets (SLD) near the accident site around the accident time. At the time of his most recent medical certificate application, the pilot reported no chronic medical conditions and no medications. The medical certificate contained the limitation "Must wear corrective lenses." The pilot's flight logbook contained entries dated between May 27, 2013, and December 28, 2017. The pilot had logged no less than 1,219.4 hours in helicopters; 212.7 hours of which were logged in the make and model of the accident helicopter. The pilot had logged 97.9 hours of simulated instrument flight time, and no flight time in actual instrument conditions. The last simulated instrument flight (0.4 hours dual received) was conducted September 30, 2015, in a Robinson R44 II helicopter. The pilot started work at Vista One Inc. on September 6, 2017, and recorded a flight in his logbook, dated 9/6/17, of .5 hours with the note "Vista 1 First Day." The pilot had logged 309.3 hours of flight time in company helicopters between September 6, 2017, and December 28, 2017. The company did not provide any training records for the pilot. The owner recalled conducting a training flight with the pilot the week before the accident but did not provide any specifics for that flight. This flight was not logged in the pilot's flight logbook. The owner mentioned that the pilot had difficulty recalling how to clear the GPS track just before the accident flight. He also stated that the pilot did not recall how to operate the throttle past the detent. He did not report any other concerns with the pilot's performance. Crewmember The powerline inspector worked for Vista One Inc. for 2 to 3 years. He lived in West Virginia and would drive to Ohio when it was time to work. According to the crewmember's family, he had been flying from platforms for line inspection and maintenance since 2004. The owner of Vista One Inc. stated that the crewmember drove from his home West Virginia the evening before the accident and met the pilot at 1G0 for work on the day of the accident. The accident site was in a dormant corn/bean field at an elevation of 620 ft msl. The wreckage came to rest about 120 ft west of power lines. There was no evidence that the helicopter impacted either the power lines or the transmission towers. There was no evidence of a postcrash fire. There were no ground scars leading up to the wreckage. The ground was frozen, and it had snowed before, during, and after the accident. Photographs provided by first responders illustrated extensive debris and disturbed ground immediately adjacent to the belly of the helicopter. The helicopter came to rest on its left side with the nose oriented on a heading of 256°. The main wreckage included the fuselage, tail boom, and main rotor system. Two main rotor blades came to rest on the ground and two main rotor blades were extended in the air. The tail boom was partially separated, and the left skid was separated, fractured into multiple pieces, and located about 20 ft south of the main wreckage. The wreckage was recovered from the scene and relocated to a secure facility for further examination. Wreckage Examination The wreckage of the helicopter was examined under the auspices of the NTSB investigator in charge. The extensive details of the wreckage examination are contained in the docket for this accident. The lower fuselage exhibited extensive upward crushing along the entire span of the fuselage. The cabin of the fuselage was crushed up from the floor/belly of the helicopter. The left side of the helicopter exhibited more upward and sideways crush as compared to the right side. The upper and lower windscreens on the left and right side were impact damaged and fragmented. The collect