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ASN Wikibase Occurrence # 233812
Last updated: 26 August 2021
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Type:Silhouette image of generic B06 model; specific model in this crash may look slightly different
Bell 206L-4 LongRanger IV
Owner/operator:Florida Keys Mosquito Control District
Registration: N173MS
MSN: 52256
Fatalities:Fatalities: 0 / Occupants: 1
Other fatalities:0
Aircraft damage: Substantial
Location:Big Pine, FL -   United States of America
Phase: Standing
Departure airport:Marathon, FL (MTH)
Destination airport:Marathon, FL (MTH)
Investigating agency: NTSB
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.

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.



Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 11 months
Download report: Final report

Revision history:

10-Mar-2020 09:41 ASN Update Bot Added

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