# NTSB CEN21LA339: Robinson Helicopter R44 II, N983HA, West Liberty, IA, July 20, 2021 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 4 · Limited · Final report - Date: July 20, 2021, 17:20 local (22:20 UTC) - Place: West Liberty, IA - Coordinates: 41.57, -91.2638 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.5700&lon=-91.2638&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: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 103560 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA339 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103560/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103560 - Page: https://openairdocs.org/ntsb/CEN21LA339 ## Probable cause The pilot’s failure to see and avoid a wire while maneuvering at low altitude during an aerial application flight, resulting in a collision with the wire. ## 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; 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) - [Maneuvering-low-alt flying: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Robinson Helicopter R44 II, 4 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=7640122), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Robinson Helicopter R44 II, 74 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7640122), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis The pilot reported that he was performing an aerial application pass when he felt a “big tug” on the helicopter. The pilot realized he had struck a wire as the helicopter pitched up and started to slow. The helicopter flew about 150 yards when the pilot felt another “huge jerk” on the rear of the helicopter. The helicopter started to spin and rotated about 2-3 times before it impacted the ground and rolled over coming to rest on its left side. On exiting the helicopter, the pilot observed the wire wrapped around the helicopter. It had cut into the tail rotor gearbox “tearing it” off the helicopter. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operations. The pilot reported that prior to conducting the aerial application pass, he circled the field and did not observe any obstructions. The pilot did not submit the National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report Form 6120.1. ## Aircraft - Registration: [N983HA](https://openairdocs.org/deregistered/N983HA-2023-11-20), registration cancelled 2023-11-20, S/N 10464, built 2004 (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: 10464 - Year built: 2004 - Engines: Lycoming IO-540-AE1A5 375 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Airworthiness certificate: Standard, Normal ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: minor; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; flight hours: 1 total, 1 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 86 °F, dew point 70 °F - Altimeter: 30.06 inHg - Observed at: KMUT, 13 nm away - METAR: KMUT 202215Z AUTO 30005KT 10SM CLR 30/21 A3006 RMK AO2 ## 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 20210720013309A](https://openairdocs.org/incident/20210720013309A), Jul 20, 2021: Robinson Helicopter Company R44 II, West Liberty, IA, Substantial damage. The main rotor mast struck a wire. The wire broke and was trailing from the helicopter. The wire became entangled in the tail rotor causing failure of the tail… ## Docket (2 files) The files NTSB released with the investigation on January 5, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103560. 1.4 MB in all. - Record of memorandum - pilot statement with on scene photos (item 1, PDF, 5 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12935808&FileExtension=pdf&FileName=ROM%20PILOT%20STATEMENT-Rel.pdf - Record of memorandum - NTSB pilot/operator 6120.1 form (item 2, PDF, 1 page, 125 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12935910&FileExtension=pdf&FileName=Record%20of%20Memorandum%20no%206120-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.