ANC23FA056

The pilot's decision to fly at a low altitude over a large body of water toward featureless terrain, which resulted in a loss of visual clues and controlled flight into terrain.

The helicopter pilot was under contract to the State of Alaska’s Department of Natural Resources (DNR) to transport scientific crews to various remote locations within the North Slope region. The accident flight departed on a visual flight rules flight from Utqiagvik, Alaska, with an anticipated brief stop at the Atqasuk airport, before continuing to remote sites to the east of Wainwright, Alaska, then returning to Utqiagvik. When the helicopter did not arrive back in Utqiagvik, search and rescue was dispatched to search for the missing helicopter. The partially submerged, fragmented helicopter wreckage was found in the shallow waters of Lake Itinik, about 30 miles east of Wainwright. Lake Itinik was a large, oval-shaped arctic lake more than three miles wide in some areas. The terrain around the lake consisted of flat, featureless, arctic tundra-covered terrain. Examination of the airframe and engine revealed no evidence of any preaccident mechanical failures or malfunctions that would have precluded normal operation. Archived satellite tracking data indicated that the helicopter was flying about 88 ft above ground level (agl) at 93 knots shortly before impacting the water. Although there was a possibility of some overcast clouds and restricted visibility in fog/mist over the accident site, there were no observations or forecasts for any significant turbulence, low-level wind shear, convective activity, or icing over the area at the time of the accident. Another pilot in the area of the accident reported clear skies with no restriction to visibility, and weather camera images near the accident site also revealed no cloud coverage and unrestricted visibility. Flight data from previous flights flown by the accident pilot revealed a pattern of high-speed, low-altitude flights similar to the flight profile of the accident flight. The helicopter was being operated over water below the operator’s requirement of being within power-off gliding distance from shore. The pilot’s decision to fly at a low altitude in flat light conditions, which obscured the features of the terrain, likely resulted in a loss of visual clues regarding the helicopter's distance from the ground. A flat, featureless lake offers little in the way of visual references for the pilot. Without terrain, landmarks, or other visual cues to help judge altitude and position, it's easy to become disoriented. This can be particularly dangerous when flying at low altitudes. The flat, reflective surface of the water can create a false horizon illusion, making it difficult for the pilot to accurately perceive the aircraft's attitude. Over a flat, featureless surface like a lake, depth perception can be impaired, making it difficult to judge the distance to the water and increasing the risk of flying too low or contacting the water. Toxicology results indicated that the pilot had used the medication cetirizine. The measured cetirizine level in blood indicates a possibility that the pilot may have been experiencing some associated impairing effects, such as mild sedation, at the time of the accident. However the investigation was not able to determine what role, if any, the effects of the pilot’s cetirizine use may have had on his operation of the helicopter.

When the accident helicopter departed PABR, which was about 55 miles from the accident site at an elevation of 49 ft, the ceiling was about 200 to 300 ft agl and visibility was about 3 to 5 statute miles. The closest weather reporting location to the accident site was Atqasuk Edward Burnell Sr. Memorial Airport (PATQ), located about 27 miles southeast of the accident site at an elevation of 101 ft. The weather conditions were light winds, visibility was 10 miles or more, and sky conditions were clear. About 5 minutes after the accident the visibility was reported as 5 miles and haze. These conditions were present for about 15 minutes and then returned to 10 miles or more. PATQ weather at 1105 AKDT, automated, wind from 290° at 3 knots, visibility 10 miles or more, sky clear below 12,000 ft, temperature 18° C, dew point 14° C, altimeter 29.90 inHg. PATQ weather at 1110 AKDT, automated, wind from 240° at 5 knots, visibility 5 miles in haze, sky clear below 12,000 ft, temperature 18° C, dew point 14° C, altimeter 29.90 inHg. The next closest reporting location was from Wainwright Airport (PAWI), Wainwright, Alaska, located 36 miles west of the accident site at an elevation of 45 ft. The weather conditions about the time of the accident were reported as visibility 9 miles, sky clear below 12,000 ft agl. Satellite imagery of the accident site revealed the presence of low stratiform clouds that extended from PABR and ended near PATQ. The Fog Stability Index indicated favorable conditions for the formation of radiation type fog. Due to fiber optic outages, there were a limited number of FAA weather camera images available. There were no images from the closest weather camera (PATQ) facing the accident site (northwest); however, images to the north revealed clear skies. The images to the southwest depicted a scattered layer of low stratiform clouds and a mid-layer of altostratus clouds. The PAWI camera images toward the accident site displayed scattered high-level clouds. The Area Forecast noted that an AIRMET for IFR conditions was current for the coastal and offshore sections over PABR to near PAWI, with ceilings below 1,000 ft agl and visibility below 3 miles in light rain, mist, and fog. The National Weather Service’s Alaska Aviation Weather Unit Flying Weather graphic valid for the time of the accident depicted marginal VFR conditions. According to the FAA Barrow Flight Service Station, the pilot received a preflight weather briefing and requested a special VFR departure. Weather camera images near the accident site revealed no cloud coverage and unrestricted visibility. A pilot from a different operator reported that he was operating in the same area as the accident helicopter. He stated he departed Utqiagvik (PABR) to the southwest on the day of the accident, between 0900 and 1000. He said there was no ceiling, no altitude restrictions, and no issues with visibility. The temperature that day was one of the warmest days he had ever seen. When he returned to Utqiagvik that night, he noticed the accident helicopter was not back yet. It was very unusual for him to be back before the accident helicopter. He called the FAA flight service center with his concern but was told they had no flight plan and no information on when the accident helicopter was returning. The accident pilot recently retired from the military; this was his first job as a pilot since retirement. He had about 1,900 hours of flight experience in helicopters. He started with the company in October of 2022. Initially he was assigned to the Bell 407 helicopter, but six months before the accident he transitioned to the Bell 206 series helicopter. As part of his initial training, the pilot completed an exam on flat-light conditions on October 21, 2022. On a follow up exam, the pilot identified the North Slope as an area conducive to flat light conditions. The pilot arrived in Utqiagvik two days before the accident flight. The accident flight was his second flight with passengers in the Utqiagvik area. According to the operator, flat light flight procedures are covered in their training program, and overwater flight procedures are covered in their Standard Operating Procedures (SOP’s). The operator’s SOP’s state that helicopters will not be operated in areas of flat featureless terrain unless the in-flight visibility is at least one mile, a visual surface reference is available which would allow for a safe landing area, and a visible horizon is present that distinguishes the sky and ground. According to the SOP’s, flat light conditions can be present in a variety of areas ranging from snow-covered terrain to over open water. Flat light is a visual condition where sunlight is diffused by, but not limited to, overcast skies, coupled with flat and featureless terrain, calm water, or snow-covered terrain. Flat light conditions in these environments contribute to the pilot’s ability to discern topographical features below making it difficult to determine the altitude and/or attitude of the aircraft. One of the hazards associated with overwater operations identified by the operator in their SOP’s is controlled flight into terrain. The operator’s SOP’s also require only float equipped aircraft (fixed or emergency pop-out floats) to be operated beyond power-off gliding distance from shore. The accident helicopter was not equipped with fixed or emergency pop-out floats. Title 14 CFR §135.207 helicopter surface reference requirements. No person may operate a helicopter under VFR unless that person has visual surface reference or, at night, visual surface light reference, sufficient to safely control the helicopter. The operator’s flight locating procedures shall be provided by: A local Flight Service Station, through the use of a filed FAA flight plan including Company phone contact; or, a designated company or customer flight monitor through the use of a Company VFR flight plan. These flight locating procedures will be immediately available to the designated flight monitor. In the event a company aircraft operating on a company flight plan is more than 60 minutes overdue from the latest ETA, or if an emergency signal is indicated by the aircraft flight following system. The following steps shall be taken by the designated flight monitor. 1. Attempt to contact the aircraft. 2. Contact other company aircraft, company personnel at the remote site, the customer or any other operators in the surrounding area and ask them to try to contact the overdue aircraft through their available communication methods. 3. Call the closest Flight Service Station, identify the flight and request any information and possible FSS contact. 4. Notify company management. Identify the aircraft and its location on the Sky Connect Tracker computer display, and explain any pertinent information about the flight. 5. If the aircraft has not been located after accomplishing steps 1 through 4 call NTSB and the FAA 24-hour response phone number to report the flight overdue. The operator reported that the accident pilot did not receive the information concerning the altitude flight restrictions that were required by the Alaska DNR permit. The operator does not have a Flight Operational Quality Assurance program and does not review flight history to detect unsafe behaviors. A chief at the Alaska DNR who had extensive knowledge of the requirements of the permit to operate in the area, was familiar with the mission the crew was conducting, and who had flown numerous times in the area reported that helicopter pilots would fly a lot higher than the minimum altitude and would only go lower because of the weather as stipulated in the permit. The Director of Operations for the operator said “they fly as high as they can and avoids flying over water in poor weather conditions.” The only time they fly low is because of poor weather. He was not sure why the pilot wou