# NTSB GAA19CA209: Bell 206, N173MS, Big Pine, FL, April 12, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: April 12, 2019, 11:38 local (15:38 UTC) - Place: Big Pine, FL - Coordinates: 24.727222, -81.389999 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=24.7272&lon=-81.3900&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Defining event: [Standing-engine(s) operating: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 3, 2020 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - NTSB case key (mKey): 99275 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA209 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99275/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99275 - Page: https://openairdocs.org/ntsb/GAA19CA209 ## Probable cause The pilot's failure to maintain helicopter control while it was being reloaded with the rotors turning in gusting wind conditions, which resulted in a rotor strike with ground equipment. ## 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: [Bell 206-L4, 8 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1182110), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/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: [Bell 206-L4, 3 cases](https://openairdocs.org/ntsb-findings/03022050/cases.md?model=1182110), [All aircraft, 52 cases](https://openairdocs.org/ntsb-findings/03022050/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Bell 206-L4, 1 case](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=1182110), [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Standing-engine(s) operating: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Bell 206-L4, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=1182110), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Standing-engine(s) operating: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Bell 206-L4, 8 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1182110), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Standing-engine(s) operating: Aircraft servicing event](https://openairdocs.org/ntsb-events/020); cases with it: [Bell 206-L4, 1 case](https://openairdocs.org/ntsb-events/020/sequence.md?model=1182110), [All aircraft, 70 cases](https://openairdocs.org/ntsb-events/020/sequence.md) ## Analysis The pilot reported that, after the fourth aerial application flight of the day, he landed and positioned the helicopter near the autoloader boom truck. He reduced engine power to flight idle, and the ground crew began the loading process. He verified that the collective position was full down and the cyclic friction was on, and he then exited the helicopter to stretch while maintaining one hand on the cyclic. The pilot reported that, immediately after, while standing next to the helicopter, he heard two "loud bangs." He immediately boarded the helicopter, the ground crew secured the truck's boom, and the pilot shut down the engine. Examination revealed that a main rotor blade had struck the truck's boom arm and that the main rotor blades sustained substantial damage. The director of aerial operations 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 the fourth aerial application flight of the day, he landed and positioned the helicopter near the autoloader boom truck. He reduced engine power to flight idle and the ground crew began the loading process. He verified the collective position was full down, set the cyclic friction to ON, and exited the helicopter to stretch while maintaining one hand on the cyclic. Immediately after, while standing next to the helicopter, he heard two "loud bangs." He immediately boarded the helicopter; the ground crew secured the boom, and the pilot shut down the engine. Upon further examination by the operator's maintenance personnel, it was determined that a main rotor blade struck the boom arm and that the main rotor blades were beyond the repair limitations, per the manufacturer's guidance. The helicopter sustained substantial damage to the main rotor blades. The director of aerial operations reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The director of aerial operations added that, at the site of the accident, the wind was 130º at 11 knots, gusting up to 19 knots. The helicopter was oriented with a southbound heading. ## Aircraft - Registration: [N173MS](https://openairdocs.org/aircraft/N173MS), registered now, S/N 52256, built 2000 (OpenAirDocs) - Reported make and model: Bell 206 (L4) - Registry model: [Bell 206-L4](https://openairdocs.org/model/bell-206-l4) (registry code 1182110) (OpenAirDocs) - Registry engine: [Allison 250-C30 series](https://openairdocs.org/engine/allison-250-c30-series) (registry code 03015, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 52256 - Year built: 2000 - Airframe hours: 3039.5 - Engines: Rolls Royce 250-C30P 650 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft - local, Public use - Operator: Florida Keys Mosquito Control District - Registered owner: Florida Keys Mosquito Control District - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 20, 2018 - Departed: MTH, Marathon, FL - Destination: MTH, Marathon, FL - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: none; private, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 4, 2018; seat: right; restraint: 4-point; flight hours: 4,212 total, 1,613 in this make and model, 3,610 as pilot in command, 31 in the last 90 days, 18 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 9 knots, gusting 15 - Visibility: 10 statute miles - Temperature: 88 °F, dew point 73 °F - Altimeter: 29.98 inHg - Observed at: KMTH, 18 nm away ## Docket (4 files) The files NTSB released with the investigation on January 8, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99275. 1.4 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479692&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photo (item 2, .PDF, 181 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479693&FileExtension=.PDF&FileName=Accident%20Photo-Master.PDF - Rcord of Converastion - DO (item 3, .PDF, 65 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479694&FileExtension=.PDF&FileName=Rcord%20of%20Converastion%20-%20DO-Master.PDF - Record of Conversation - Pilot (item 4, .PDF, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479695&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Pilot-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.