ERA21FA362

The pilot’s decision to continue the visual flight rules flight into deteriorating weather conditions during a dark night and over unlit terrain, which resulted in spatial disorientation and a subsequent loss of helicopter control.

The pilot, who was also the owner of the company, and a pilotrated passenger were transporting a revenue-paying passenger on a chartered helicopter flight. The flight began on the morning of the accident with an approximately 200 nautical-mile flight to their destination before returning several hours later under visual flight rules. During the return trip, they stopped at an airport to refuel. About halfway through the subsequent flight, they encountered moderate to heavy rain showers. The passenger sent a text message to his spouse stating they landed in a field because “bad storms popped up” and they were waiting for it to blow over before resuming their flight. The message included a photograph that showed a grass field, gray skies, and rain on the helicopter’s window. According to recorded flight track data, after departing the field, the pilot made a series of meandering track changes before proceeding to a nearby small airport where they stayed for about 5 minutes. Weather data indicated that after takeoff, the helicopter remained in areas of low ceilings and rain for the remainder of the flight. By this point in the flight, the sun had set and the end of civil twilight had passed. The helicopter subsequently passed 5 miles west of a city, then passed 2 miles east of a large powerplant before entering a large national wildlife refuge, a remote area covered with dense forest. Shortly thereafter, the helicopter made a series of shallow left and right track changes. During the last 25 seconds of the flight, the helicopter entered a rapidly descending right turn and descended to ground impact. The calculated rate of descend reached nearly 4,000 feet per minute during the descent. The fragmentation of the wreckage and damage to surrounding trees revealed that the helicopter was in a 90° right bank as it came through the trees and impacted terrain. Postaccident examination of the airframe, flight control system components, transmission, rotor system, and engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The helicopter was certified for operation in visual meteorological conditions (both day and night) and was not certified for operation in instrument meteorological conditions. While the helicopter was equipped with modern avionics that included tools like synthetic vision, as well as an autopilot system, the pilot’s proficiency in the use of the systems could not be determined based on available information. Some or all the ethanol detected by postmortem toxicological testing in the pilot’s tissue may have been from sources other than consumption. It is unlikely that ethanol or impairment was a factor in the accident. The weather conditions at the time of and preceding the accident consisted of low ceilings, low visibility, and rain with marginal visual meteorological conditions expected through most of the area. Once the helicopter passed the city and powerplant that contained ground reference lighting, and entered the national forest, the dark night conditions and sparse lighting along the flightpath would have made it even more difficult for the pilot to recognize and recover from a loss of control due to spatial disorientation. Based on the wreckage distribution, which was consistent with a high-energy impact, coupled with the known low visibility present at the time of the accident, it is likely that the pilot experienced spatial disorientation and lost control of the helicopter.

On September 15, 2021, at 2046 eastern daylight time, a Robinson R66 helicopter, N888DV, was destroyed when it was involved in an accident at the Oconee National Forest, near Monticello, Georgia. The commercial pilot, the pilot-rated passenger, and one other passenger sustained fatal injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 135 on-demand charter flight. The pilot, who was the owner of the company, and a pilot-rated passenger, a part time company employee, were transporting a revenue passenger to southern Georgia and north Florida for personal business. The spouse of the passenger confirmed that the passenger chartered the flight to “look at properties” in the area and was supposed to return later that evening. The flight originated at Fulton County Executive Airport/Charlie Brown Field (FTY) Atlanta, Georgia, about 0700 and proceeded south, making a stop in Reidsville, Georgia, before continuing to Finlayson Farm Airport (9FL8) Greenville, Florida, where they landed and stayed for several hours before departing on the return flight under visual flight rules. During the return trip, they landed at Thomasville Regional Airport (TVI), Thomasville, Georgia, where they refueled with 40 gallons of fuel. Automatic dependent surveillance–broadcast (ADS–B) data indicated the flight departed TVI at 1840, then proceeded on a northerly track for about 80 nautical miles near the town of Andersonville, Georgia. At 1937, the passenger’s spouse sent a text message her husband and asked him, “What’s your ETA to home?” He responded with a photograph taken with his mobile device and stated “Approx 9:30, bad storm pop up had to land in field. It’s blowing over now.” The photograph showed a grass field, gray skies and rain on the helicopter’s window (figure 1). After departing the field to the west, the helicopter proceeded north and followed a powerline right-of-way for about 4 nautical miles (nm) before reversing course and following the same right-of-way south for about 3 nm. The helicopter then turned left on a southeast track for about 15 nm before making a left turn to the northeast where they made an approach and landing to Perry-Houston County Airport (PXE) Perry, Georgia about 2015. Five minutes later, the helicopter continued to the north, following a six-lane divided highway (Interstate 75); it passed 5 miles west of downtown Macon, Georgia, then about 10 minutes later passed about 2 miles east of a large powerplant shortly before entering the Piedmont National Wildlife Refuge, a remote area covered with dense forest. The passenger sent a second series of text messages to his spouse during this en route portion of the flight and included a screen shot of the weather radar and their location (figure 1). Figure 1 – Screen captures of mobile telephone messages from the passenger. These included a photo of the weather about 1937 and a weather radar composite image (right). About 2043, the helicopter made a series of left and right track changes (figure 2), then during the last 25 seconds of the flight, when the helicopter was at 1,650 ft above mean sea level , it entered a rapidly descending right turn where the vertical speed decreased steadily from level flight to a nearly 4,000 ft per minute descent; at 2046, the ADS-B signal was lost. The helicopter collided with trees and hilly terrain at an elevation of 570 ft. A witness south of the accident site reported hearing a low-flying helicopter and stated that at the time it was “very rainy.” Figure 2 - Orthographic image of helicopter flight path (white overlay), looking south. An additional background witness, who was also the mechanic and a helicopter pilot, stated that the operator, Atlanta Helicopters Inc, used a Robinson R-44 for charter operations, and at the time of the flight, that helicopter was down for maintenance. The owner had used the “new” R-66 for the accident flight. The owner had acquired the helicopter several months before. The witness further stated that the pilot-rated passenger was a relatively “low time” helicopter pilot with several hundred hours and likely accompanying the pilot to get some extra turbine flight experience. AIRCRAFT INFORMATION The helicopter was equipped with a Garmin GDU 1060L 10-inch display and a GTN 750xi with GPS Navigation and Com; the Garmin GDU 1060L was a 10.6” horizontal format display that could accommodate Primary Flight Display (PFD) information and a multifunction display (MFD) side by side within the same unit. The display was pilot-selectable for PFD or PFD/MFD presentation, and was equipped with Helicopter Synthetic Vision, which would create a graphic display of the terrain in front of the helicopter based on a geographic database. It was driven by the Garmin GTN 750xi GPS/NAV/COMM/MFD, which performed the basic functions of GPS and VOR navigation, as well as a communication radio. The combination of the two components could display maps, weather, traffic, airport information, and synthesized terrain in various configurations. In addition, a HeliSAS autopilot was installed. The HeliSAS autopilot system in the accident helicopter was primarily a Stability Augmentation System (SAS), which would maintain a steady helicopter attitude by applying corrective inputs to the cyclic. The autopilot would not provide any collective or pedal inputs. Additional modes of operation could provide heading hold, altitude hold, and navigation functionality. Control inputs from the autopilot system were felt as a light cyclic centering force. The autopilot sensed helicopter attitude using a combination of sensors in the flight control computer and the onboard attitude source. The computer then sent signals to the servomotors which were connected to the bottom of the cyclic in the control tunnel. The helicopter was not certified for operation under instrument flight rules and was only certified for day/night visual flight rules operation. According to the operator’s operations specifications (D085) section a. “The certificate holder is authorized to conduct operations under 14 CFR Part 135 using the aircraft identified on this operations specification,” registration number N206TJ, which was a Robinson R-44-II. METEROLOGICAL INFORMATION The recorded weather conditions at Covington Municipal Airport (CVC), Atlanta, Georgia, located about 27 miles north of the accident site at an elevation of 820 ft included, wind from 090° at 5 knots, 5 statute miles visibility, moderate rain, scattered clouds at 500 ft, broken 2,300 ft, and overcast at 11,000 ft, temperature 20° C, dewpoint 20° C; and an altimeter setting of 30.02 inches of mercury. The recorded weather conditions at Thomaston-Upson County Airport (OPN), Thomaston, GA, about 28 miles southwest of the accident site at an elevation of 798 ft included wind from 070° at 4 knots, 10 statute miles visibility, moderate drizzle, overcast 500 ft, temperature 21° C, dewpoint 21° C, and an altimeter setting of 30.00 inches of mercury. The recorded weather conditions at Middle Georgia Regional Airport (MCN), Macon, GA, located about 28 miles south of the accident site at an elevation of 354 ft included wind from 060° at 7 knots, 10 statute miles visibility, light rain, few clouds 4,500 ft, broken clouds 8,500 ft, overcast 9,000 ft, temperature 22° C, dewpoint 22° C, and an altimeter setting of 29.97 inches of mercury. The closest National Weather Service (NWS) Weather Surveillance Doppler Radar (WSR-88D) was located at Atlanta Regional Airport-Falcon Field (FFC) Atlanta, Georgia about 42 miles north-northwest of the accident site. The FFC 0.5° base reflectivity image for 2047 with the flight track overlaid is included as figure 3. The base reflectivity inset image depicted echoes of 20 to 37 dBZ along the flight track, and the accident site located about 4 miles from an isolated cell with maximum echo