- Date
- August 14, 2017, 13:15 local (18:15 UTC)
- Place
- Westby, WI
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N97UPRobinson Helicopter R44
- Defining event
- Maneuvering-low-alt flying: Low altitude operation/event
- Weather
- Visual (VMC) · Day
- Status
- Completed · report November 27, 2017
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA/ FSDO
- FAA report
- 20170814013389A
- Case key
- 95833
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 see and avoid power lines while maneuvering at low altitude.
Findings · 2
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 helicopter pilot reported that, during an agricultural application flight, he performed a "high…[reconnaissance]" pass over the field and observed houses, tree lines, and power lines surrounding the field. He added that he descended for the first pass, about 70 mph and 100 to 150 ft above ground level, and as he approached the end of the field, he "suddenly became aware of two [additional] large power lines stretched out in front of [him] at eye level and closing fast." He further added that he "instinctively pulled up on the collective and back on the cyclic," and the fuselage cleared the wire, but suddenly there was a "violent lurch" when the tail rotor contacted the wire. Subsequently, the helicopter started to "spin out of control," the pilot braced for impact, and the helicopter impacted the terrain. The fuselage, tailboom, and main rotor sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Factual narrative
The helicopter pilot reported that, during an aerial application flight, he performed a "high recon [reconnaissance]" pass over the field and observed houses, tree lines, and power lines surrounding the field. He added that he descended for the first pass, about 70 mph and 100 to 150 ft. above ground, and as he approached the end of the field, he "suddenly became aware of two [additional] large power lines stretched out in front of [him] at eye level and closing fast." He further added that, he "instinctively pulled up on the collective and back on the cyclic" and the fuselage cleared the wire, but suddenly there was a "violent lurch" when the tail rotor contacted the wire. Subsequently, the helicopter started to "spin out of control," the pilot braced for impact, and the helicopter impacted the terrain. The fuselage, tail boom, and main rotor sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Aircraft
- Registration
- N97UP
- Reported as
- Robinson Helicopter R44 (UNDESIGNAT)
- Category
- Helicopter
- Serial number
- 0237
- Built
- 1996
- Airframe hours
- 5,353
- Engine
- Lycoming O-540-F1B5, 260 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial application · Part 137
- Operator
- Mf Helicopters LLC.
- Registered owner
- Mf Helicopters LLC.
- Airworthiness certificate
- Special, Restricted (Special)
- Last inspection
- Annual · March 31, 2017
- Departed
- 57C · East Troy, WI
- Destination
- NONE · Westby, WI
- 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
- 34
- Injuries
- None
- Certificate
- Commercial
- Instrument ratings
- Helicopter
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- March 14, 2016
- Seat
- Right
- Restraint
- 3-point
- Flight hours
- 986 total · 820 in this make and model · 930 as pilot in command · 250 in the last 90 days · 190 in the last 30 days · 6 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 120° at 5 knots
- Visibility
- 10 statute miles
- Temperature
- 73 °F
- Observed at
- NONE
Docket · 4
The files NTSB released with the investigation on October 30, 2017, on NTSB’s docket system: statements, records, photos and specialists’ reports. 771 KB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.