# NTSB GAA17CA491: Robinson Helicopter R44, N97UP, Westby, WI, August 14, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 14, 2017, 13:15 local (18:15 UTC) - Place: Westby, WI - Coordinates: 43.660278, -90.861114 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.6603&lon=-90.8611&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 27, 2017 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA/ FSDO - NTSB case key (mKey): 95833 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA17CA491 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95833/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95833 - Page: https://openairdocs.org/ntsb/GAA17CA491 ## Probable cause The pilot's failure to see and avoid power lines while maneuvering at low altitude. ## 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: [Robinson Helicopter R44, 21 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=7640120), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) - [Object/animal/substance: tower/antenna (incl guy wires)](https://openairdocs.org/ntsb-findings/03022017): Environmental issues › Physical environment · Awareness of condition (probable cause); cases with it: [Robinson Helicopter R44, 2 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md?model=7640120), [All aircraft, 55 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Robinson Helicopter R44, 26 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7640120), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Robinson Helicopter R44, 43 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7640120), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Robinson Helicopter R44, 56 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7640120), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter pilot reported that, during an agricultural application flight, he performed a "high…[reconnaissance]" pass over the field and observed houses, tree lines, and power lines surrounding the field. He added that he descended for the first pass, about 70 mph and 100 to 150 ft above ground level, and as he approached the end of the field, he "suddenly became aware of two [additional] large power lines stretched out in front of [him] at eye level and closing fast." He further added that he "instinctively pulled up on the collective and back on the cyclic," and the fuselage cleared the wire, but suddenly there was a "violent lurch" when the tail rotor contacted the wire. Subsequently, the helicopter started to "spin out of control," the pilot braced for impact, and the helicopter impacted the terrain. The fuselage, tailboom, and main rotor sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. ## Factual narrative The helicopter pilot reported that, during an aerial application flight, he performed a "high recon [reconnaissance]" pass over the field and observed houses, tree lines, and power lines surrounding the field. He added that he descended for the first pass, about 70 mph and 100 to 150 ft. above ground, and as he approached the end of the field, he "suddenly became aware of two [additional] large power lines stretched out in front of [him] at eye level and closing fast." He further added that, he "instinctively pulled up on the collective and back on the cyclic" and the fuselage cleared the wire, but suddenly there was a "violent lurch" when the tail rotor contacted the wire. Subsequently, the helicopter started to "spin out of control," the pilot braced for impact, and the helicopter impacted the terrain. The fuselage, tail boom, and main rotor sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. ## Aircraft - Registration: [N97UP](https://openairdocs.org/aircraft/N97UP), registered now, S/N 0237, built 1996 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER R44 (UNDESIGNAT) - Registry model: [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44) (registry code 7640120) (OpenAirDocs) - Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 0237 - Year built: 1996 - Airframe hours: 5353 - Engines: LYCOMING O-540-F1B5 260 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Mf Helicopters LLC. - Registered owner: Mf Helicopters LLC. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 31, 2017 - Departed: 57C, EAST TROY, WI - Destination: NONE, Westby, WI - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; injuries: none; commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review March 14, 2016; seat: right; restraint: 3-point; flight hours: 986 total, 820 in this make and model, 930 as pilot in command, 250 in the last 90 days, 190 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 5 knots - Visibility: 10 statute miles - Temperature: 73 °F - Observed at: NONE ## 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 20170814013389A](https://openairdocs.org/incident/20170814013389A), Aug 14, 2017: Robinson Helicopter R44, Westby, WI, Substantial damage. Helicopter agriculture spraying event . Pilot did a high altitude recon of the spray site. The field was 286 ft wide by 1,400 ft long. A house at the west end,… ## Docket (4 files) The files NTSB released with the investigation on October 30, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95833. 771 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 463 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40457456&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation (Pilot in Command) (item 2, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40457457&FileExtension=.PDF&FileName=Record%20of%20Conversation%20(Pilot%20in%20Command)-Master.PDF - Memorandum for Record (Pilot in Command) (item 3, .PDF, 56 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40457458&FileExtension=.PDF&FileName=Memorandum%20for%20Record%20(Pilot%20in%20Command)-Master.PDF - Accident Photo (Courtesy of FAA) (item 4, .PDF, 1 photo, 192 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40457459&FileExtension=.PDF&FileName=Accident%20Photo%20(Courtesy%20of%20FAA)-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.