# NTSB GAA19CA139: Airbus A350, N350ST, Eureka, AK, February 18, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: February 18, 2019, 14:55 local (23:55 UTC) - Place: Eureka, AK - Coordinates: 61.774166, -147.123336 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.7742&lon=-147.1233&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 26, 2019 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 98999 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA139 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98999/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98999 - Page: https://openairdocs.org/ntsb/GAA19CA139 ## Probable cause The pilot's selection of unsuitable terrain for landing on snow-covered mountainous terrain with steep rocks above, which resulted in loose rocks damaging the main rotor blades and the subsequent loss of helicopter controllability. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Eurocopter France AS350B2, 3 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=8680973), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Terrain: mountainous/hilly terrain](https://openairdocs.org/ntsb-findings/03021010): Environmental issues › Physical environment · Decision related to condition (probable cause); cases with it: [Eurocopter France AS350B2, 1 case](https://openairdocs.org/ntsb-findings/03021010/cases.md?model=8680973), [All aircraft, 329 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Eurocopter France AS350B2, 2 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=8680973), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Eurocopter France AS350B2, 1 case](https://openairdocs.org/ntsb-findings/03022020/cases.md?model=8680973), [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Eurocopter France AS350B2, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=8680973), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Maneuvering-hover: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Eurocopter France AS350B2, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=8680973), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Eurocopter France AS350B2, 2 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=8680973), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-hover: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Eurocopter France AS350B2, 4 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=8680973), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter pilot reported that, while transporting snow skiers, he landed on a 20º slope below the mountain peak, where he directed the guide and two skiers to unload with the engine running. The pilot saw loose rocks from the peak above fall into the main rotor disk, and after the skiers were clear of the helicopter, he raised the collective and brought the helicopter to a hover. He added that, while hovering, he did not feel any controllability issues, so he repositioned the helicopter up the mountain about 30 ft and "toed in" to unload additional skiers. After the remaining skiers unloaded, the pilot started flying the helicopter down the mountain so that he could shut down the engine and examine the main rotor blades. The pilot added that, about 10 seconds later, the helicopter began to shake violently. He initiated a forced landing, but about 150 ft above the trees, the "flight controls became progressively hard to control," and the helicopter pitched up. Immediately, he lowered the nose and collective, and about 30 ft above the snow-covered ground, the main rotor disk struck trees, and the helicopter subsequently impacted terrain. The helicopter sustained substantial damage to the main rotor blades, fuselage, tailboom, and tail rotor blades. The director of operations reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. ## Factual narrative The helicopter pilot reported that, while transporting snow skiers, he landed on a 20º slope below the mountain peak, where he directed the guide and two skiers to unload with the engine running. The pilot saw loose rocks from the peak above fall into the main rotor disk, and after the skiers were clear of the helicopter, he raised the collective and brought the helicopter to a hover. While hovering, he did not feel any controllability issues, so he repositioned the helicopter up the mountain about 30 feet and "toed in" to unload additional skiers. After the remaining skiers unloaded, the pilot flew the helicopter down the mountain to shut down and examine the main rotor blades. About 10 seconds into the flight, the helicopter began to shake violently. He initiated a forced landing, but about 150 feet above the trees, the "flight controls became progressively hard to control", and the helicopter pitched nose up. Immediately, he lowered the nose and collective and about 30 feet above the snow-covered ground, the main rotor disk struck trees and the helicopter impacted the terrain. The helicopter sustained substantial damage to the main rotor blades, fuselage, tail boom and tail rotor blades. The director of operations reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. ## Aircraft - Registration: [N350ST](https://openairdocs.org/deregistered/N350ST-2020-02-28), registration cancelled 2020-02-28, S/N 2789, built 1994 (OpenAirDocs) - Reported make and model: AIRBUS A350 (B2) - Registry model: [Eurocopter France AS350B2](https://openairdocs.org/model/eurocopter-france-as350b2) (registry code 8680973) (OpenAirDocs) - Registry engine: [Honeywell LTS101-700D-2](https://openairdocs.org/engine/honeywell-lts101-700d-2) (registry code 33825, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 2789 - Year built: 1993 - Airframe hours: 7085.2 - Engines: Honyewell LTS-101-700D 732 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Operator: Rota Aviation Consulting Llc, doing business as Ravco - Registered owner: Rota Aviation Consulting Llc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 9, 2019 - Departed: Sutton, AK - Destination: Sutton, AK - Equipment: Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: none; private, flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review February 16, 2018; restraint: 4-point; flight hours: 6,000 total, 2,500 in this make and model, 4,850 as pilot in command, 8 in the last 90 days, 8 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 14 knots - Visibility: 10 statute miles - Lowest ceiling: 4,400 ft overcast - Temperature: 34 °F, dew point 28 °F - Altimeter: 29.67 inHg - Observed at: PAAQ, 57 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 20190218010359A](https://openairdocs.org/incident/20190218010359A), Feb 18, 2019: Eurocopter France AS350B2, Glacier View, AK, Substantial damage. AS-350 was conducting heliski operations and unloading skiers during toe-in maneuver on ~20 degree slope at approx. 5500 foot level. Slope was direct lighted… ## Docket (3 files) The files NTSB released with the investigation on June 5, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98999. 1.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 834 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40473262&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation - Pilot (item 2, .PDF, 58 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40473263&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Pilot-Master.PDF - Accident Photo (item 3, .PDF, 1 photo, 185 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40473264&FileExtension=.PDF&FileName=Accident%20Photo-Master.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.