Tyonek, AK, USA
N1905A
PIPER PA-18AS
The noninstrument-rated private pilot had spent the previous 4 days and nights conducting a solo sheep hunting trip and was returning home when the accident occurred. Before departing the remote, mountain airstrip, the pilot contacted a Federal Aviation Administration (FAA) Flight Service Station (FSS) on his satellite phone for a weather briefing and asked whether visual flight rules (VFR) flight was recommended for his route that night. The flight service specialist (FS-S) provided the pilot with the terminal area forecast for the destination airport; information from the current Area Forecast, which indicated cloud ceilings around 5,000 ft mean sea level (msl), marginal VFR conditions, and rain; and a pilot report from a nearby mountain pass, which advised that VFR was not recommended. The pilot asked several times about a specific mountain pass, and although the FS-S described the conditions at that pass based on FAA weather camera images and expressed pessimism about the prospect of the pilot attempting VFR flight, she did not provide the pilot with the information contained in the Area Forecast for the pass, which indicated instrument flight rules conditions, rain, and mist, as well as isolated moderate turbulence in the area below 6,000 ft msl. The FS-S also did not provide weather radar information, which showed the intended route of flight under an extensive area of precipitation, including areas of moderate or greater intensity. Despite the pessimism of the FS-S on the prospect of the pilot attempting a VFR flight to his intended destination that night, had the FS-S provided the current forecast information for the specific pass and the regional turbulence found in the Area Forecast, as well as a description of the current weather radar depiction for his intended route of flight, the pilot would have had a more accurate picture of the weather over the route of flight. Data obtained from an onboard GPS unit for the last several minutes of flight showed the airplane conduct two descending, spiraling turns. The airplane continued to descend before the data terminated. The airspeed during the last several minutes of the flight ranged from 49 knots to 82 knots. The pilot departed on the flight about 10 minutes before sunset. Twilight conditions during much of the flight would have provided the pilot with some illumination from which to see; however, cloud cover would have decreased the amount of illumination during this period, as would the end of civil twilight, which occurred about an hour after takeoff. Thus, dark night conditions would have existed for at least the last 14 minutes of the flight, as the flight proceeded over a remote area devoid of cultural lighting. The dark night conditions, lack of available ground lighting, and possible instrument meteorological conditions present at the time were conducive to the development of spatial disorientation, and the airplane's flight track is consistent with the known effects of spatial disorientation. Whether the pilot may have been experiencing fatigue before and/or during the flight given his hunting activities of the previous 4 days, it could not be determined based on the available information. Based on the available radar weather and airplane track data, it is likely that the airplane flew into or came very close to an area of moderate or greater precipitation just before the accident; however, the extent to which the weather contributed to the pilot's spatial disorientation could not be determined. The pilot chose to depart at a time that would have required him to operate in dark night conditions with a lack of cultural lighting, eliminating his reference to a visual horizon and requiring reliance on the airplane's flight instruments for attitude control. The dark night conditions would also have precluded the detection and avoidance of weather.
HISTORY OF FLIGHTOn August 23, 2017, about 2245 Alaska daylight time (AKDT), a wheel-equipped Piper PA-18AS-125 airplane, N1905A, impacted remote, tree-covered terrain about 31 miles northwest of Tyonek, Alaska. The private pilot sustained fatal injuries and the airplane was destroyed. The airplane was registered to and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 visual flight rules (VFR) personal flight. Night instrument meteorological conditions were present along the airplane's route of flight at the time of the accident and no flight plan was filed. The flight originated from a remote airstrip near Telaquana Lake, located in the Lake Clark National Park and Preserve, about 2130, and was destined for Merrill Field (MRI), Anchorage, Alaska. The pilot's wife reported that the pilot was returning from a solo Dall sheep hunting trip in the Alaska Range. The pilot departed from MRI on August 19 about 1630 and arrived at the remote airstrip about 1930. She reported that the length of the hunting trip was open-ended with no set return date. The pilot placed three separate phone calls via satellite phone to the Federal Aviation Administration (FAA) Kenai Flight Service Station (FSS), Kenai, Alaska, on the night of the accident requesting weather information for his route of flight. The Kenai FSS is located at the Kenai Municipal Airport (PAEN), Kenai. Each call was dropped due to interruptions of satellite coverage. The same flight service specialist (FS-S) spoke with the pilot on all three occasions. The public docket contains the transcripts for each phone call. The first phone call was at 1950 and lasted about 1 minute. The pilot reported that he was south of Merrill Pass and requested an outlook briefing for flight via Merrill Pass to Anchorage for the night of the accident and for the following day. He asked, "whether or not it's going to remain VFR from Merrill Pass back into Anchorage tonight and into tomorrow." The FS-S provided the terminal forecast for Anchorage before the call was dropped. The second phone call, at 1956, lasted about 3 minutes. The pilot reported that he was near Merrill Pass on the west side and requested a "quick weather brief" asking if VFR flight from Merrill Pass or Telaquana Pass to Anchorage would be recommended for that night. The FS-S provided the Merrill Pass forecast, which called for marginal VFR (MVFR) conditions, the area forecast (FA), and the Anchorage terminal forecast before the call was dropped. About 2100, the pilot contacted his wife via a satellite phone and asked her to retrieve weather information for a flight to MRI. She instructed the pilot to call her back in about 5 minutes; however, the pilot never called back. The third and final phone call to the FSS was at 2108 and lasted about 10 minutes. The pilot asked if VFR flight across the Alaska Range or in the Merrill Pass area was recommended that night. The FS-S responded by saying, "…I don't have anything that's giving me a good report…" and provided the pilot with information from the current FA, which included the current airman's meteorological information (AIRMET) and regional ceiling, visibility, precipitation information, and information from a pilot report (PIREP) advising that VFR was not recommended on the east side of Lake Clark Pass (about 34 miles southwest of the accident site). The pilot again asked about conditions at Merrill Pass, to which the FS-S responded with a comprehensive description of what she was seeing from the FAA Merrill Pass "low" weather camera. The FS-S indicated the FAA Merrill Pass "high" weather camera was out of service. Following a request from the pilot, she also provided a comprehensive description of what she was seeing on the FAA Beluga weather camera. Despite being asked several times about Merrill Pass, the FS-S did not provide the pilot with the forecast for instrument flight rules (IFR) ceilings, rain, and mist that was indicated for the pass in the current FA. Despite being asked directly for turbulence information for the Cook Inlet and Matanuska-Susitna Valley area, the FS-S did not provide the pilot with the forecast for isolated moderate turbulence below 6,000 ft above mean sea level (msl) for the region found in the current FA. Additionally, the FS-S did not provide the pilot with the current Kenai weather radar information. The pilot indicated that he was not in a hurry to get home, and then asked about conditions the next day. The FS-S provided a synoptic summary of frontal systems and expected precipitation and wind and indicated that she was, "…not seeing anything too much for the passes." The pilot requested forecast information valid for 24-48 hours from that time. The FS-S stated "…that occluded front basically right now still over Kodiak Island there pushing into uh Cook Inlet/Susitna Valley definitely got your rain looking at that low coming right over by four o'clock in the afternoon tomorrow right over us. I'm showing IFR conditions right in your area where you're coming from so that's around four o'clock in the afternoon now tomorrow okay that occluded front is going to be right over the top of us into Prince William Sound there's going to be isolated areas where it's going to be in the clear but they're talking about the drying of those winds the Turnagain Arm winds there drying out that moisture at the same time you got those winds cause you got turbulence going to be in the forecast there…" The pilot asked, "So it's going to get worse is what you're saying?" to which the FS-S responded, "yeah basically…" The FS-S then stated, "…I didn't know how else to relay that to you I just cannot tell you yeah go ahead and try to come home through Merrill Pass it's not looking too good especially what they said about the Alaskan range through the Aleutian areas there so I would not chance that." The pilot then indicated his intent to, "probably go tonight" and started to file a VFR flight plan, but the call was lost before the flight plan was completed. About 2220, the pilot's wife received a text message from the pilot stating that he was flying over Kenibuna Lake and that he should be home around 2300. She did not receive any further communications from the pilot. She reported that he was not rushed to return home nor was there any sort of emergency that required him to depart when he did. Upon departing from the airstrip and heading to the northeast, the route of flight was over mountainous terrain. Continuing east, the route was overwater as the airplane crossed Kenibuna Lake and Chakachamna Lake. Once past the mountainous terrain and continuing to the east, the area consisted mainly of hills before reaching the Cook Inlet and the Matanuska-Susitna Valley. An overview of the route of flight, along with the remote airstrip the pilot departed from, the accident site, and the destination airport is shown in figure 1. Figure 2 shows the last portion of the flight. Figure 1 – Map of the route of flight, obtained from the onboard GPS unit (courtesy of the NTSB). Figure 2 – Map of the last portion of the route of flight, obtained from the onboard GPS unit (courtesy of the NTSB). Merrill Pass, which is depicted on a VFR sectional map, is shown in figure 3. Figure 3 – Map showing the location of Merrill Pass (courtesy of vfrmap.com). About 2245, the U.S. Air Force Alaska Rescue Coordination Center at Joint Base Elmendorf-Richardson, Alaska, received a 406 MHz emergency locator transmitter (ELT) signal from the airplane. The wreckage was located the next morning in remote, tree-covered terrain about 1/4 mile south of the Chakachatna River as shown in figure 4. Figure 4 – Aerial view of the wreckage (courtesy of the NTSB). PERSONNEL INFORMATION The pilot's wife reported that he was a conservative and safe pilot who was cognizant of the dangers of flying in Alaska, particularly with bad weather in the mountains. She stated that he always carried a satellite phone when he flew and would always call for a weather briefing. In addition, she stated that the pilot had no issues with alcohol, drugs, fatigue, or stress. She further reported that the pilot was a fit, healthy person and lived an active lifestyle. The pilot did not hold an instrument rating. A review of the pilot's logbook, as of the last entry on July 20, 2017, showed no actual instrument flight experience, 23 hours of simulated instrument experience, and 66.1 hours of night experience. FS-S The FS-S was based at the Kenai FSS in Kenai. Her air traffic control experience began in the U.S. Navy where she served as an air traffic controller (ATC) from 1990 to 1994. Between 1998 and 1999, she was training as a control tower operator with the FAA. From 2000 to 2005, she worked as a FS-S with the FAA. From 2005 until 2006, she worked as a certified professional controller at an FAA approach control center. She worked outside of aviation from 2007 until August 2016 when she was rehired by the FAA as a FS-S and began working in Kenai. The FS-S had completed all required training for her duties. She possessed a second-class FAA medical certificate and her last ATC physical examination was conducted in October 2016. AIRCRAFT INFORMATION The airplane was not equipped for instrument flight and did not have an onboard weather system. An examination of the airplane's maintenance records revealed no evidence of uncorrected mechanical discrepancies with the airframe and engine. METEOROLOGICAL INFORMATION An Automated Weather Observing System was located at PAEN and was located about 44 miles southeast of the accident location at an elevation of about 100 ft msl. Automated reports from PAEN during the times surrounding the accident time are as follows: [2053 AKDT] METAR PAEN 240453Z AUTO 00000KT 10SM OVC060 12/12 A2958 RMK AO2 RAE34 SLP017 P0001 T01220122 TSNO= [2153 AKDT] METAR PAEN 240553Z AUTO 00000KT 10SM -RA FEW050 OVC060 12/12 A2958 RMK AO2 RAB0458 SLP017 P0000 60009 T01220117 10133 20122 56008 TSNO= [2253 AKDT] METAR PAEN 240653Z AUTO 00000KT 5SM -RA BR SCT050 OVC060 12/12 A2957 RMK AO2 SLP016 P0004 T01170117 TSNO= [2353 AKDT] METAR PAEN 240753Z AUTO 26003KT 5SM -RA BR SCT049 OVC055 12/12 A2957 RMK AO2 SLP015 P0006 T01170117 TSNO= At 2253, PAEN reported a calm wind, visibility of 5 miles, light rain, mist, scattered clouds at 5,000 ft above ground level (agl), ceiling overcast at 6,000 ft agl, temperature of 12° Celsius (C) and a dew point temperature of 12°C, altimeter setting of 29.57 inches of mercury; remarks included: station with a precipitation discriminator, 0.04 inches of precipitation since 2153 AKDT, no thunderstorm information. An AIRMET advisory SIERRA for "mountains occasionally obscured in clouds/precipitation" was issued at 2010 and was active for the accident site at the accident time. An Area Forecast that included the forecast for the accident location was issued by the National Weather Service (NWS) Alaska Aviation Weather Unit (AAWU) at 2010. The Area Forecast included the AIRMET information, and for the region (excluding the following Alaska/Aleutian Range region) forecasted few clouds at 1,500 ft msl, scattered clouds at 2,500 ft msl, broken to overcast clouds at 4,500 ft msl, with clouds tops to 15,000 ft msl and clouds layered about that to flight level 260, with light rain, occasional broken clouds at 2,500 ft msl with light rain and mist. Along the Alaska and Aleutian Ranges, it forecasted occasional broken clouds at 1,500 ft msl and visibilities 3-5 statute miles and light rain and mist, and isolated ceilings below 1,000 ft agl with visibilities below 3 statute miles with moderate rain and mist. For Merrill Pass, the Area Forecast forecasted IFR ceilings with moderate rain and mist. For the region, the Area Forecast forecasted isolated moderate turbulence below 6,000 ft msl and isolated moderate icing between 8,000-15,000 ft msl with the freezing level at 6,000 ft msl. Various graphics were issued by the AAWU applicable to the accident time. The graphics identified IFR or MVFR conditions (as shown in figure 5), isolated moderate icing between 8,000 to 15,000 ft msl, isolated moderate turbulence below 6,000 ft msl, and light or moderate precipitation (as shown in figure 6) at the accident location, at or near the accident time. Figure 5 – Flying weather graphic issued at 2000 and valid between 2000 on August 23, 2017, and 0200 on August 24, 2017 (courtesy of the AAWU). Figure 6 – Surface Chart issued at 2100 and valid for 2200 (courtesy of the AAWU). WSR-88D Level-II weather radar imagery was obtained from near Kenai (PAHG). PAHG was located approximately 34 miles southeast of the accident site at an elevation of about 242 ft msl. Assuming standard refraction and considering the 0.95° beam width for the WSR-88D radar beam, the PAHG 1.4° tilt would have "seen" altitudes above the accident location of between about 4,300 and 7,800 ft msl. The PAHG imagery surrounding the accident period identified reflectivity features consistent with light to extreme intensities of precipitation in the region and adjacent to the accident site as shown in figure 7. Figure 7 – PAHG 1.4° Level-II reflectivity product from a sweep initiated at 2245:47 (courtesy of the NTSB). WSR-88D Level-III composite weather radar imagery from PAHG for the times surrounding the third Kenai FSS telephone weather briefing was obtained. This composite imagery identified an extensive area of reflectivity surrounding the accident location and extending east through the Anchorage area as shown in figure 8. Figure 8 – PAHG Level-III composite reflective image, from a volume scan initiated at 2056 (courtesy of the NTSB). The white dot denotes the accident location. Astronomical Conditions The astronomical data obtained from the U.S. Naval Observatory for the accident site, indicated that sunset was 2141, end of civil twilight was 2231, moonrise was 0918, and moonset was 2226. The phase of the moon was listed as waxing crescent with 5 percent of the moon's visible disk illuminated. WRECKAGE AND IMPACT INFORMATION On August 24, the NTSB IIC and the Alaska State Troopers (AST) traveled to the accident site via helicopter. The wreckage was located at the base of a 100-foot-tall cottonwood tree at an elevation of about 455 ft msl as shown in figure 9. Figure 9 – View of the empennage and the right wing (courtesy of the NTSB). All portions of the airplane were accounted for at the wreckage site. The fuselage, both wings, and the cockpit were severely damaged with extensive deformation. Flight control continuity could not be established onsite due to extensive impact damage. The engine and propeller were buried underneath the airframe. Various hunting and camping gear were scattered throughout the wreckage. The wreckage was recovered and transported to a secure facility in Wasilla, Alaska, for further examination. During the examination, no preimpact mechanical malfunctions or failures with the airframe and engine were noted. The total estimated weight of the cargo recovered from the wreckage was about 178 lbs. MEDICAL AND PATHOLOGICAL INFORMATION The Alaska State Medical Examiner, Anchorage, Alaska, conducted an autopsy of the pilot. The cause of death was attributed to multiple blunt force injuries. The FAA's Bioaeronautical Research Sciences Laboratory, Oklahoma City, Oklahoma, performed toxicology tests on specimens from the pilot; testing was negative for ethanol and drugs. Carbon monoxide and cyanide tests were not performed. TESTS AND RESEARCH The pilot's cell phone and a GPS device were extracted from the wreckage and submitted to the NTSB Vehicle Recorder Division, Washington, DC, for examination. The cell phone sustained severe impact damage. The data on the microSD card was not pertinent to the investigation. The GPS unit, a Garmin Aera 660, sustained severe impact damage. Data was recovered from the device. This data included parameters such as date, time, longitude, latitude, airspeed, altitude, and track as recorded by the device. Graphical overlays, such as figure 1 and figure 2, using the recove
The noninstrument-rated pilot's decision to initiate a visual flight rules flight into dark night, marginal visual flight rules to instrument flight rules conditions, which resulted in a loss of control due to spatial disorientation.
Source: NTSB Aviation Accident Database
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