# NTSB CEN23LA341: Robinson Helicopter R44 II, N644ME, Arthur, IL, July 31, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 4 · Limited · Final report - Date: July 31, 2023, 14:00 local (19:00 UTC) - Place: Arthur, IL - Coordinates: 39.7173, -88.35816 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.7173&lon=-88.3582&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: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: FAA - Springfield FSDO - NTSB case key (mKey): 192767 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA341 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192767/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192767 - Page: https://openairdocs.org/ntsb/CEN23LA341 ## Probable cause The pilot’s failure to maintain clearance from trees during a low-level aerial application flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Effect on equipment (probable cause); cases with it: [Robinson Helicopter R44 II, 9 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md?model=7640122), [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md) - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Awareness of condition (probable cause); cases with it: [Robinson Helicopter R44 II, 9 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md?model=7640122), [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md) - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Robinson Helicopter R44 II, 29 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=7640122), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/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 II, 45 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7640122), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## Analysis The pilot reported that he had confirmed that there were no powerlines to avoid before entering a field to perform spray operations. While spraying next to a tree line and approaching a road, the pilot could not recall whether there were powerlines or not. The pilot reported that while making a precautionary maneuver to avoid any potential powerlines, he had forgotten about the tree line. The helicopter struck a tree branch, and subsequently impacted terrain, which resulted in substantial damage to the fuselage, empennage, and main rotor blades. The pilot reported that there were no mechanical malfunctions or failures that would have precluded normal operation. ## Aircraft - Registration: [N644ME](https://openairdocs.org/aircraft/N644ME), registered now, S/N 13439, built 2013 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER COMPANY R44 II - Registry model: [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii) (registry code 7640122) (OpenAirDocs) - Registry engine: [Lycoming IO-540-AE1A5](https://openairdocs.org/engine/lycoming-io-540-ae1a5) (registry code 41899, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 13439 - Year built: 2013 - Airframe hours: 917.58 - Engines: Lycoming IO-540-AE1A5 245 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Ras Aviation LLC - Registered owner: Ras Aviation LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 18, 2023 - Departed: Tuscola, IL ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: serious; commercial; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review April 15, 2023; seat: front; restraint: 3-point; flight hours: 403 total, 96 in this make and model, 328 as pilot in command, 72 in the last 90 days, 52 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 57 °F - Altimeter: 30.13 inHg - Observed at: KMTO, 15 nm away - METAR: KMTO 312053Z AUTO 06007KT 020V080 10SM CLR 28/14 A3013 RMK AO2 SLP197 T02780144 56010 ## 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 20230731010519A](https://openairdocs.org/incident/20230731010519A), Jul 31, 2023: Robinson Helicopter Company R44 II, Arcola, IL, Destroyed. The pilot was engaged in part 137 agricultural spraying. The pilot stated that they cleared the field with a survey pass. During the first spray pass parallel… ## Docket (2 files) The files NTSB released with the investigation on September 28, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192767. 3.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15979782&FileExtension=pdf&FileName=N644ME%206120.1_Redacted-Rel.pdf - Photos (item 2, PDF, 2 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15980199&FileExtension=pdf&FileName=Docket%20Photo%20Array-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.