# NTSB GAA19CA238: Aerospatiale AS350, N350DL, Sula, MT, April 30, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: April 30, 2019, 10:15 local (16:15 UTC) - Place: Sula, MT - Coordinates: 45.859443, -113.968055 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.8594&lon=-113.9681&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 20, 2020 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 99359 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA238 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99359/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99359 - Page: https://openairdocs.org/ntsb/GAA19CA238 ## Probable cause The pilot's failure to maintain adequate clearance from ground equipment, which resulted in a tail rotor blade impact. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [American Eurocopter AS350B3, 1 case](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=1145004), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) - [Object/animal/substance: ground equipment](https://openairdocs.org/ntsb-findings/03022050): Environmental issues › Physical environment · Effect on operation (probable cause); cases with it: [American Eurocopter AS350B3, 2 cases](https://openairdocs.org/ntsb-findings/03022050/cases.md?model=1145004), [All aircraft, 52 cases](https://openairdocs.org/ntsb-findings/03022050/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [American Eurocopter AS350B3, 1 case](https://openairdocs.org/ntsb-events/220/sequence.md?model=1145004), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-hover: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [American Eurocopter AS350B3, 8 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1145004), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter pilot reported that, after an agricultural application flight, he set the bucket down in a predetermined operations zone near a semi-truck loading hopper to be refilled. He added that another truck arrived to top off the semi-truck hopper, which emitted fertilizer dust and led to the pilot being concerned that it would deteriorate visibility. He advised the ground crew that he was going to temporarily move out of the operations zone. The pilot reported that he set the bucket in the new temporary operations zone. As the skid steer approached, he eased the helicopter backward to keep the other ground equipment in his view. The pilot heard a "bang," disconnected the helicopter from the long-line, and then landed the helicopter without further incident. Postaccident examination revealed that the auger from the semi-truck hopper was fully extended behind the helicopter and that a tail rotor blade had sustained substantial damage. The pilot reported that he might have backed the helicopter into the extended auger. The pilot 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, after an aerial application flight, he set the bucket down in a pre-determined operations zone near a semi-truck loading hopper to be refilled. He added that another truck arrived to top off the semi-truck hopper, which emitted fertilizer dust that caused the pilot concerns for his deteriorating visibility. He advised the ground crew that he was going to move out of the operations zone temporarily. The pilot reported that he set the bucket in the new temporary operations zone. As the skid steer approached, he eased the helicopter backward to keep the other ground equipment in his view. The pilot heard a "bang", disconnected from his long-line, and landed the helicopter without further incident. Postaccident examination revealed that the auger from the semi-truck hopper was fully extended behind the helicopter and tail rotor blade sustained substantial damage. The pilot suspected that he backed the helicopter into the extended auger. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. ## Aircraft - Registration: [N350DL](https://openairdocs.org/aircraft/N350DL), registered now, S/N 4508, built 2008 (OpenAirDocs) - Reported make and model: Aerospatiale AS350 (B3) - Registry model: [American Eurocopter AS350B3](https://openairdocs.org/model/american-eurocopter-as350b3) (registry code 1145002) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-2B1](https://openairdocs.org/engine/turbomeca-arriel-2b1) (registry code 60056, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 4508 - Year built: 2008 - Airframe hours: 1103.2 - Engines: Safran Arriel 2B1 749 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Mission Mountain Helicopters - Registered owner: Pj Helicopter Llc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 24, 2019 - Departed: Soula, MT - Destination: Soula, MT - Equipment: ADS-B, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; injuries: none; commercial, airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land, multi-engine sea, single-engine sea; instrument ratings: airplane, helicopter; medical: class 2, without waivers/limitations; last flight review March 15, 2019; seat: right; restraint: 3-point; flight hours: 8,773 total, 3,125 in this make and model, 8,700 as pilot in command, 26 in the last 90 days, 11 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: 10,000 ft overcast - Temperature: 36 °F ## 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 20190430003639A](https://openairdocs.org/incident/20190430003639A), Apr 30, 2019: American Eurocopter LLC AS350B3, Sula, MT, Minor damage. On April 30, 2019 at 1015 an American Eurocopter AS350B3, N350DL, registered to pj helicopter LLC, operated by mission mountain helicopters, struck the boom… ## Docket (2 files) The files NTSB released with the investigation on May 13, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99359. 3.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472861&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photo (item 2, .PDF, 1 photo, 128 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472862&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.