# NTSB ANC23LA032: Robinson Helicopter R44 II, N704T, Skwentna, AK, May 9, 2023 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 4 · Limited · Final report - Date: May 9, 2023, 12:00 local (20:00 UTC) - Place: Skwentna, AK - Coordinates: 61.774586, -151.7413 - Nearby events: https://openairdocs.org/map.md?lat=61.7746&lon=-151.7413&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: VFR encounter with IMC](https://openairdocs.org/ntsb-events/401) - Highest injury: Minor injuries - Injuries: 2 minor, 1 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 - NTSB case key (mKey): 139291 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23LA032 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/139291/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=139291 - Page: https://openairdocs.org/ntsb/ANC23LA032 ## Probable cause The pilot's failure to maintain adequate altitude/clearance from terrain while maneuvering in adverse weather conditions, which resulted in a dynamic rollover. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Ceiling/visibility/precip: whiteout](https://openairdocs.org/ntsb-findings/03035060): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause) - [Info processing/decision: identification/recognition](https://openairdocs.org/ntsb-findings/02041510): Personnel issues › Action/decision · Pilot (probable cause) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause) - [Ceiling/visibility/precip: snow](https://openairdocs.org/ntsb-findings/03035045): Environmental issues › Conditions/weather/phenomena · Decision related to condition (probable cause) ## Analysis The pilot reported that, he was flying uphill over an area of snow-covered, mountainous terrain, when he encountered flat light and whiteout conditions, which made it difficult to discern topographical features. In an attempt to maintain visual reference with the ground, he turned the helicopter to the right to fly back down the hill. Subsequently, the right landing gear skid contacted terrain and the helicopter entered a dynamic rollover to the right, resulting in substantial damage to the fuselage, tail boom, and powertrain system. The pilot reported that there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: VFR encounter with IMC](https://openairdocs.org/ntsb-events/401) (defining event) - [Maneuvering: Loss of visual reference](https://openairdocs.org/ntsb-events/402) - [Maneuvering: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120) ## Aircraft - Registration: [N704T](https://openairdocs.org/aircraft/N704T), registered now, S/N 10343, built 2004 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER R44 II - Registry model: [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii) (registry code 7640123) (OpenAirDocs) - Registry engine: [Lycoming IO-540-AE1A5](https://openairdocs.org/engine/lycoming-io-540-ae1a5) (registry code 41899, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 10343 - Year built: 2004 - Airframe hours: 3191.4 - Engines: LYCOMING IO-540-AE1A5 260 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 135 - Operator: Willow Creek Aviation, doing business as Remote Alaska Air - Registered owner: C & J Leasing LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 22, 2022 - Departed: SKW, Skwentna, AK - Destination: Skwentna, AK - Flight plan: Company VFR - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: minor; commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 19, 2023; seat: front; restraint: 3-point; flight hours: 10,570 total, 398 in this make and model ## Weather - Conditions: Day - Wind: 130° at 9 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 48 °F, dew point 28 °F - Altimeter: 29.82 inHg - Observed at: PAWS, 64 nm away - METAR: PAWS 091956Z AUTO 13009G18KT 10SM CLR 09/M02 A2982 RMK AO2 SLP104 T00941022 ## 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 20230509002709A](https://openairdocs.org/incident/20230509002709A), May 9, 2023: Robinson Helicopter R44 II, Skwentna, AK, Substantial damage. Pilot and two passengers (180 lbs. And 160 lbs.) Plus gear (90LBS) in R44-II helicopter conducting survey around noon at first of three survey points. Fuel on… ## Docket (2 files) The files NTSB released with the investigation on July 7, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=139291. 6.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 6.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15502631&FileExtension=pdf&FileName=ANC23LA032%206120_Redacted-Rel.pdf - Investigative photograph (item 2, PDF, 1 page, 172 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15498189&FileExtension=pdf&FileName=ANC23LA032%20Investigative%20Photographs-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.