# NTSB ANC23FA061: Piper PA-18-150, N4481Z, Skwentna, AK, August 9, 2023 - Type: NTSB accident investigation - Classification: Accident · Fatal · Class 3 · Field · Final report - Date: August 9, 2023, 12:15 local (20:15 UTC) - Place: Skwentna, AK - Coordinates: 62.462453, -152.35866 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=62.4625&lon=-152.3587&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 192841 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23FA061 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192841/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192841 - Page: https://openairdocs.org/ntsb/ANC23FA061 ## Probable cause An impact with terrain for reasons that could not be determined because the airplane was not recovered due to the inaccessible nature of the accident site. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Piper PA-18-150, 9 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=7101828), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Piper PA-18-150, 8 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=7101828), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) ## Analysis The pilot was conducting a commercial on-demand charter flight to shuttle two individuals in support of a remote hunting excursion. The accident flight passenger and a friend chartered with the pilot’s company to transport them and their hunting gear to a base camp. Three days before the accident, the pilot and the two hunters departed from the company’s base airport and conducted a scouting trip in the pilot’s Cessna 206 airplane to check out the area for a possible hunting location and a suitable landing area for the pilot’s PA-18 airplane. On the morning of the accident, about 0830, the pilot and the two hunters departed the company’s base airport in the Cessna 206 airplane, and they landed at a remote airstrip in an area about 50 miles southeast of the planned base camp. The hunters and hunting gear were offloaded and the pilot returned to the company base in the Cessna 206 to pick up his PA-18 airplane. The pilot returned to the remote airstrip in the PA-18 and loaded one hunter and his gear for the flight to the hunting location. The pilot informed the other hunter he was expected to return in about 2 hours to pick him up and transport him to the planned hunting location. The airplane departed the remote airstrip about 1150, and no further communications were received from the pilot or passenger. About 1600, after the airplane did not return, the hunter contacted family members using a satellite messaging device to see if they were aware of the overdue airplane’s status. Over the next several hours, family members and friends attempted to communicate with the pilot and passenger’s satellite messaging devices, but those attempts were unsuccessful. Search and rescue operations began that evening, but initial search flights were suspended due to poor weather. The following day, the airplane wreckage was located at the bottom of an estimated 500 to 600 ft deep narrow ravine. Due to the unique challenges posed by the accident location, neither the occupants nor the wreckage were recovered from the accident site. Weather information near the accident site was limited due to a lack of weather reporting facilities in the remote accident location. Weather advisories active for the area that included the accident site included mountains occasionally obscured by clouds/precipitation with deteriorating conditions. Based upon available weather data and the impact evidence, it is likely that the pilot entered an area of reduced visibility and was unable to maneuver the airplane to avoid the terrain before the airplane impacted the ravine. Although the known circumstances of the accident are consistent with a controlled flight into terrain event, the factual information available was limited because the wreckage was not recovered and no autopsy or toxicology of the pilot could be performed; therefore, whether other circumstances may have contributed to the accident could not be determined. ## Factual narrative According to the pilot’s family, the pilot was equipped with a personal ZOLEOTM satellite communicator device that could provide message and location sharing data. The device was equipped with SOS and Check-in features that may be manually activated by an individual. Based on available data from the device, the device provided location sharing data about every 12 minutes during the flights on the day of the accident. The last location data was transmitted at 1215 about 9 miles southeast of the accident site near the West Fork of the Yentna River. There were no manually activated SOS or Check-in messages provided by the device. On August 9, 2023, about 1215 Alaska daylight time, a Piper PA-18-150 airplane, N4481Z, was destroyed when it was involved in an accident about 60 miles northwest of Skwentna, Alaska. The pilot and passenger sustained fatal injuries. The airplane was being operated as a Title 14 Code of Federal Regulations Part 135 on-demand charter flight. The airplane was operated by Willow Creek Aviation, LLC, in support of a remote sheep hunting excursion. The passenger and a friend chartered Willow Creek Aviation, LLC, to transport them and their hunting gear to the Dillinger River area. On August 6, 2023, the pilot and the two hunters departed from the Big Lake Airport (PAGQ), Big Lake, Alaska, and conducted a scouting trip in the pilot’s Cessna 206 airplane to check out the Dillinger River area for a possible hunting location and a suitable landing area for the pilot’s PA-18 airplane. The passengers were planning for an 8-to-10-day hunting trip. On the morning of the accident, about 0830, the pilot and the two hunters departed PAGQ in Willow Creek Aviation’s Cessna 206 airplane and they landed at a remote airstrip in an area referred to as Donkey Creek. The hunters and hunting gear were offloaded and the pilot returned to PAGQ to pick up his PA-18, the accident airplane. The pilot returned to Donkey Creek in the PA-18 and loaded one hunter and his gear for the flight to the hunting location near the Dillinger River (see Figure 1). The pilot informed the other hunter he was expected to return in about 2 hours to pick him up and transport him to the planned hunting location. Figure 1. Planned flight overview and accident site location. Based on a cellular phone video from the other hunter, the airplane departed from Donkey Creek about 1150, and no further communications were received from the pilot or passenger. About 1600, after the airplane did not return to Donkey Creek, the hunter contacted family members using a satellite messaging device to see if they were aware of the overdue airplane’s status. Over the next several hours, family members and friends attempted to communicate with the pilot and passenger’s satellite messaging devices, but those attempts were unsuccessful. About 2130, a Federal Aviation Administration (FAA) alert notice was issued for the overdue airplane. Search and rescue operations began that evening by theAlaska Air National Guard Rescue Coordination Center (AKRCC). Initial search flights were then suspended due to poor weather in the identified search area. On August 10th, about 0930, the airplane wreckage was located by the AKRCC at the bottom of an estimated 500 to 600 ft deep narrow ravine of the West Fork of the Yentna River, also known as Shellabarger Pass in Denali National Park and Preserve (see Figures 2 and 3). Figure 2. Accident site location (airplane circled in red) Figure 3. Airplane wreckage in bottom of ravine On August 9, 2023, about 1215 Alaska daylight time, a Piper PA-18-150 airplane, N4481Z, was destroyed when it was involved in an accident about 60 miles northwest of Skwentna, Alaska. The pilot and passenger sustained fatal injuries. The airplane was being operated as a Title 14 Code of Federal Regulations Part 135 on-demand charter flight. The airplane was operated by Willow Creek Aviation, LLC, in support of a remote sheep hunting excursion. The passenger and a friend chartered Willow Creek Aviation, LLC, to transport them and their hunting gear to the Dillinger River area. On August 6, 2023, the pilot and the two hunters departed from the Big Lake Airport (PAGQ), Big Lake, Alaska, and conducted a scouting trip in the pilot’s Cessna 206 airplane to check out the Dillinger River area for a possible hunting location and a suitable landing area for the pilot’s PA-18 airplane. The passengers were planning for an 8-to-10-day hunting trip. On the morning of the accident, about 0830, the pilot and the two hunters departed PAGQ in Willow Creek Aviation’s Cessna 206 airplane and they landed at a remote airstrip in an area referred to as Donkey Creek. The hunters and hunting gear were offloaded and the pilot returned to PAGQ to pick up his PA-18, the accident airplane. The pilot returned to Donkey Creek in the PA-18 and loaded one hunter and his gear for the flight to the hunting location near the Dillinger River (see Figure 1). The pilot informed the other hunter he was expected to return in about 2 hours to pick him up and transport him to the planned hunting location. Figure 1. Planned flight overview and accident site location. Based on a cellular phone video from the other hunter, the airplane departed from Donkey Creek about 1150, and no further communications were received from the pilot or passenger. About 1600, after the airplane did not return to Donkey Creek, the hunter contacted family members using a satellite messaging device to see if they were aware of the overdue airplane’s status. Over the next several hours, family members and friends attempted to communicate with the pilot and passenger’s satellite messaging devices, but those attempts were unsuccessful. About 2130, a Federal Aviation Administration (FAA) alert notice was issued for the overdue airplane. Search and rescue operations began that evening by the Alaska Air National Guard Rescue Coordination Center (AKRCC). Initial search flights were then suspendeddue to poor weather in the identified search area. On August 10th, about 0930, the airplane wreckage was located by the AKRCC at the bottom of an estimated 500 to 600 ft deep narrow ravine of the West Fork of the Yentna River, also known as Shellabarger Pass in Denali National Park and Preserve (see Figures 2 and 3). Figure 2. Accident site location (airplane circled in red) Figure 3. Airplane wreckage in bottom of ravine Weather information near the accident site was limited due to a lack of weather reporting facilities in the remote accident location. At 0722 and 1215, the Alaska Aviation Weather Unit (AAWU) issued Airmen’s Meteorological Information advisories SIERRA, active for the area that included the accident site, for mountains occasionally obscured by clouds/precipitation with conditions deteriorating. Aviation-related graphic products issued by the AAWU applicable to the accident time forecasted marginal visual flight rules conditions over or very near the accident site and precipitation across the region. The 3 closest FAA weather cameras were located about 35 miles west, 25 miles southwest, and 26 miles south of the accident site. There were no weather cameras in Shellabarger Pass. The pilot’s logbook was not obtained during the investigation. The pilot’s total flight time was recorded from his most recent FAA airman medical application dated November 16, 2022. On August 11th, the day after the wreckage was discovered, the National Transportation Safety Board (NTSB) investigator-in-charge and Denali National Park rangers traveled to the accident site location but were unable to access the accident site due to steep and unstable terrain conditions. The airplane wreckage was photographed by helicopter, and an NTSB drone was deployed to descend into the canyon to document the accident site and airplane wreckage. Airplane debris and non-aircraft gear were located on the canyon wall about 400 ft above the main wreckage. Following the accident, multiple attempts of occupant recovery and reconnaissance flights were conducted by the National Park Service (NPS). On September 28th, the NPS suspended recovery operations due to several hazards associated with the accident site location and, according to the NPS, any future recovery operations would be evaluated if environmental conditions improve. ## Aircraft - Registration: [N4481Z](https://openairdocs.org/aircraft/N4481Z), registered now, S/N 18-8816, built 1969 (OpenAirDocs) - Reported make and model: PIPER PA-18-150 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-8816 - Year built: 1969 - Airframe hours: 2652 - Engines: LYCOMING O-320-A25 180 horsepower reciprocating - Damage: Destroyed - Flight: Business, Part 135 - Operator: Willow Creek Aviation, LLC, doing business as Remote Air Alaska - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 15, 2023 - Departed: Skwentna, AK - Destination: Same as departure - Equipment: Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: fatal; commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2; seat: front; toxicology performed; flight hours: 10,000 total ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 1,800 ft broken - Temperature: 57 °F, dew point 54 °F - Altimeter: 29.58 inHg - Observed at: PAPT, 26 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20230809008789A](https://openairdocs.org/incident/20230809008789A), Aug 9, 2023: Piper PA-18-150, Skwentna, AK, Destroyed, 2 fatal. Aircraft crash involving pilot with one passenger departed uncontrolled airfield at donkey creek Alaska located northeast of Skwentna Alaska en route to drop… ## Docket (8 files) The files NTSB released with the investigation on May 16, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192841. 153 MB in all. - Meteorology specialist's factual report (item 1, PDF, 20 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16533014&FileExtension=pdf&FileName=WX_ANC23FA061_Specialists_Factual-Rel.pdf - Accident area documentation (item 2, PDF, 7 pages, 9.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16539104&FileExtension=pdf&FileName=ANC23FA061%20Skwentna,%20AK%20-%20Site%20Images-Rel.pdf - Witness - area weather description and location (item 3, PDF, 3 pages, 919 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16539114&FileExtension=pdf&FileName=Witness%20-%20Area%20Weather%20Description%20and%20Location-Rel.pdf - Record of conversation - Mr. Hendricks (2nd hunter) (item 4, PDF, 2 pages, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16539084&FileExtension=pdf&FileName=ROC%20Hendricks-Rel.pdf - FAA interview summary - hendricks (2nd hunter) (item 5, PDF, 1 page, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16539094&FileExtension=pdf&FileName=Joshua%20Hendricks%20interview%20summary%20conducted%20by%20ASI%20Brian%20Boucher-Rel.pdf - Excerpt of aircraft records (item 6, PDF, 2 pages, 135 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16538683&FileExtension=pdf&FileName=Excerpt%20of%20Aircraft%20Records_Redacted-Rel.pdf - Zoleo data (item 7, CSV, 1 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16537494&FileExtension=csv&FileName=Zoleo%20CSV%20Adjusted%20Date%20Time-Rel.csv - Video - accident flight takeoff (item 8, MOV, 5.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16539185&FileExtension=MOV&FileName=IMG_5949-Rel.MOV From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.