# NTSB ERA21LA121: Robinson Helicopter R66, N660TN, Knoxville, TN, January 30, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: January 30, 2021, 09:45 local (14:45 UTC) - Place: Knoxville, TN · Back yard of residence located at 3000 River Haven Point, Knoxville, TN - Coordinates: 35.801686, -84.145919 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.8017&lon=-84.1459&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 102576 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA121 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102576/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102576 - Page: https://openairdocs.org/ntsb/ERA21LA121 ## Probable cause The pilot’s failure to maintain directional control of the helicopter, which resulted in rear portion of the right skid contacting the ground and a subsequent dynamic rollover. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Robinson Helicopter R66, 12 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7640130), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R66, 2 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=7640130), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Robinson Helicopter R66, 5 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7640130), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Other: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Robinson Helicopter R66, 3 cases](https://openairdocs.org/ntsb-events/097/sequence.md?model=7640130), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md) ## Analysis The pilot performed a preflight inspection of the helicopter, which was positioned in the yard of a residence on a slight incline. After starting the engine, and completing the checklist, he lifted to a hover at 6 ft. The helicopter then began to rotate in a counterclockwise direction and the helicopter’s nose pitched up. The rear portion of the right skid contacted the ground and the helicopter to rolled onto its right side. The helicopter’s main rotor, fuselage, and tailboom were substantially damaged. A posaccident examination of the helicopter revealed no evidence of any preimpact mechanical failures or malfunctions of the helicopter that would have precluded normal operation. Given this information, it is likely that the pilot failed to maintain directional control of the helicopter while transitioning into the hover, and the helicopter experienced a dynamic rollover when the right rear skid contacted the sloped ground. ## Aircraft - Registration: [N660TN](https://openairdocs.org/deregistered/N660TN-2025-04-22), registration cancelled 2025-04-22, S/N 0565, built 2014 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER CO R66 (NO SERIES) - Registry model: [Robinson Helicopter R66](https://openairdocs.org/model/robinson-helicopter-r66) (registry code 7640130) (OpenAirDocs) - Registry engine: [Rolls-Royce 250-C300/A1](https://openairdocs.org/engine/rolls-royce-250-c300-a1) (registry code 54232, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 0565 - Year built: 2014 - Airframe hours: 681.6 - Engines: ROLLS-ROYC 250-C300/A1 300 horsepower turbo shaft - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 2, 2020 - Destination: TYS, Knoxviile, TN - Airport: PVT, Yard, runway NONE, 20 × 20 ft, grass/turf - Equipment: ADS-B, Electronic flight bag or handheld device, Electronic primary flight display, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; injuries: none; commercial, private; airplane ratings: multi-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review July 27, 2020; seat: right; restraint: 3-point; flight hours: 8,829 total, 187 in this make and model, 8,622 as pilot in command, 51 in the last 90 days, 14 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 9,000 ft overcast - Temperature: 30 °F, dew point 21 °F - Altimeter: 30.26 inHg - Observed at: KTYS, 8 nm away - METAR: KTYS 301453Z 02007KT 10SM OVC090 M01/M06 A3026 RMK AO2 SLP254 T10111061 52001 ## 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 20210130001879A](https://openairdocs.org/incident/20210130001879A), Jan 30, 2021: Robinson Helicopter Co R66, Knoxville, TN, Substantial damage. On 1/30/2021 at approximately 0930L, N660TN was attempting to take off from a private residence in Knoxville, TN. The aircraft was parked at an approximante… ## Docket (6 files) The files NTSB released with the investigation on July 15, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102576. 11.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 7.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12048883&FileExtension=pdf&FileName=NTSB%206120%20Recd%202%2011%202021_Redacted-Rel.pdf - Record of NTSB conversation (item 2, PDF, 3 pages, 171 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12046722&FileExtension=pdf&FileName=Record%20of%20NTSB%20Conversation_Redacted-Rel.pdf - FAA inspector statement (item 3, PDF, 2 pages, 162 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12185644&FileExtension=pdf&FileName=FAA%20Inspector%20Statement-Rel.pdf - Diagram of accident site - FAA produced (item 4, PDF, 1 page, 488 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12185131&FileExtension=pdf&FileName=FAA%20Produced%20On-Site%20Diagram-Rel.pdf - Investigative photographs (item 5, PDF, 8 pages, 8 photos, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12195712&FileExtension=pdf&FileName=Investigative%20Photographs_ERA21LA121-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 6, PDF, 1 page, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12048631&FileExtension=pdf&FileName=Fully%20Executed%20Wreckage%20Release_ERA21LA121_Redacted-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.