GAA19CA209

NTSB accident investigation · Bell 206 · Big Pine, FL · April 12, 2019

Accident · No injuriesData collectionFinal report
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.

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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.

Use of equip/info: aircraft controlPersonnel issues › Task performance · PilotBell 206-L4: 8 casesAll aircraft: 9,295 casesProbable cause
Object/animal/substance: ground equipmentEnvironmental issues › Physical environment · Effect on operationBell 206-L4: 3 casesAll aircraft: 52 casesProbable cause
Wind: gustsEnvironmental issues › Conditions/weather/phenomena · Effect on operationBell 206-L4: 1 caseAll aircraft: 1,199 casesProbable cause

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.