# NTSB ANC23LA036: Piper PA31, N34WM, Point Thomson, AK, May 17, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: May 17, 2023, 12:22 local (20:22 UTC) - Place: Point Thomson, AK · 1/4 mile south of the airport - Coordinates: 70.136, -146.29002 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=70.1360&lon=-146.2900&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-IFR final approach: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Alaska Regional Office - Parties: FAA/FSDO - NTSB case key (mKey): 192218 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23LA036 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192218/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192218 - Page: https://openairdocs.org/ntsb/ANC23LA036 ## Probable cause The pilot’s inadvertent descent below the published minimum descent altitude, while operating in flat light conditions, which resulted in controlled flight into terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-31-350, 13 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7103110), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Attention/monitoring: task monitoring/vigilance](https://openairdocs.org/ntsb-findings/02021520): Personnel issues › Psychological · Pilot; cases with it: [Piper PA-31-350, 2 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md?model=7103110), [All aircraft, 330 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md) - [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-31-350, 2 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md?model=7103110), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md) - [Light condition: flat light](https://openairdocs.org/ntsb-findings/03036025): Environmental issues › Conditions/weather/phenomena · Contributed to outcome (probable cause); cases with it: [Piper PA-31-350, 2 cases](https://openairdocs.org/ntsb-findings/03036025/cases.md?model=7103110), [All aircraft, 42 cases](https://openairdocs.org/ntsb-findings/03036025/cases.md) - [Terrain: snowy/icy terrain](https://openairdocs.org/ntsb-findings/03021030): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Piper PA-31-350, 1 case](https://openairdocs.org/ntsb-findings/03021030/cases.md?model=7103110), [All aircraft, 77 cases](https://openairdocs.org/ntsb-findings/03021030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-IFR final approach: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120) (defining event); cases with it: [Piper PA-31-350, 3 cases](https://openairdocs.org/ntsb-events/120/sequence.md?model=7103110), [All aircraft, 1,074 cases](https://openairdocs.org/ntsb-events/120/sequence.md) - [Approach-IFR final approach: Loss of visual reference](https://openairdocs.org/ntsb-events/402); cases with it: [Piper PA-31-350, 1 case](https://openairdocs.org/ntsb-events/402/sequence.md?model=7103110), [All aircraft, 242 cases](https://openairdocs.org/ntsb-events/402/sequence.md) ## Analysis The pilot reported that while established on an RNAV GPS instrument approach to a remote airport, flat light conditions made it difficult to discern topographical features of the snow-covered terrain below. Prior to reaching the decision height altitude, the pilot said he looked outside for the runway environment, but the flat light condition caused him to spend more time looking outside and he became disorientated. When he looked back at the airplane’s instruments, he noticed the airplane was below the glide path and initiated a go-around maneuver; however, the airplane subsequently impacted snow-covered terrain. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N34WM](https://openairdocs.org/aircraft/N34WM), registered now, S/N 31-7305125, built 1973 (OpenAirDocs) - Reported make and model: PIPER PA31 (350) - Registry model: [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350) (registry code 7103110) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 31-7305125 - Year built: 1973 - Airframe hours: 19217 - Engines: Lycoming LTIO-540-J2B 360 horsepower reciprocating; Lycoming TIO-540-J2B 360 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 135 - Operator: JuniPogo LLC, doing business as 70 North - Registered owner: 70 North LLC - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, May 8, 2023 - Departed: PASC, Deadhorse, AK - Destination: Same as departure - Flight plan: IFR - Airport: 37AA, Point Thomson Airstrip - Equipment: Auto-pilot, ADS-B, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 30; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review November 6, 2022; seat: left; restraint: 3-point; flight hours: 1,636 total, 89 in this make and model, 1,558 as pilot in command, 110 in the last 90 days, 45 in the last 30 days, 5 in the last 24 hours - Pilot-rated passenger; age 47; injuries: none; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: right; restraint: 3-point; flight hours: 7,145 total ## Weather - Conditions: Instrument (IMC), Day - Wind: 60° at 6 knots - Visibility: 1 statute miles - Lowest ceiling: 1,500 ft broken - Temperature: 27 °F, dew point 23 °F - Altimeter: 30.21 inHg - Observed at: PASC, 45 nm away - METAR: PASC 172018Z 06006KT 1SM R06/3500VP6000FT -SN BR FEW005 BKN015 OVC028 M03/M05 A3021 RMK AO2 P0001 T10331050 ## 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 20230517003279A](https://openairdocs.org/incident/20230517003279A), May 17, 2023: Piper PA-31-350, Point Thomson, AK, Substantial damage. The flight departed pasc at 2002UTC, according to the flight log. This corresponds with ads-b/radar data showing the aircraft airborne at 2003UTC. Departure… ## Docket (2 files) The files NTSB released with the investigation on October 20, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192218. 11.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 11.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15589332&FileExtension=pdf&FileName=NTSB_6120%20Signed_Redacted-Rel.pdf - Photos (item 2, PDF, 3 pages, 456 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15589208&FileExtension=pdf&FileName=Photos-Rel.pdf 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.