- Date
- April 12, 2019, 11:38 local (15:38 UTC)
- Place
- Big Pine, FL
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Standing
- Aircraft
- N173MSBell 206
- Defining event
- Standing-engine(s) operating: Loss of control on ground
- Weather
- Visual (VMC) · Day
- Status
- Completed · report March 3, 2020
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Case key
- 99275
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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 · 3
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
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
- Reported as
- Bell 206 (L4)
- Category
- Helicopter
- Serial number
- 52256
- Built
- 2000
- Airframe hours
- 3,039.5
- Engine
- 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
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 56
- Injuries
- None
- Certificates
- 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
The files NTSB released with the investigation on January 8, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.4 MB in all.