- Date
- April 18, 2018, 11:00 local (16:00 UTC)
- Place
- Sonora, TX
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N4487DRobinson Helicopter R44
- Defining event
- Maneuvering-low-alt flying: Low altitude operation/event
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 24, 2018
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20180418003799A
- Case key
- 97156
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 clearance from trees while maneuvering at a low altitude.
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, while he was spotting deer, the helicopter hit a treetop, damaging the tail rotor. The helicopter began to spin, and the pilot closed the throttle. He landed the helicopter, and it then rolled onto its left side. The helicopter sustained substantial damage to the tailboom and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. The pilot's recommendation was to fly at a higher and safer altitude.
Factual narrative
The pilot reported that, while spotting deer, the helicopter hit the top of a tree damaging the tail rotor. The helicopter began to spin, and the pilot closed the throttle. The helicopter landed and rolled onto its left side. The helicopter sustained substantial damage to the tail boom and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. The pilot's recommendation was to fly at a higher and safer altitude.
Aircraft
- Registration
- N4487D
- Reported as
- Robinson Helicopter R44 (UNDESIGNAT)
- Category
- Helicopter
- Serial number
- 1654
- Built
- 2006
- Airframe hours
- 3,719.6
- Engine
- Lycoming O-540-F1B5, 260 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial observation · Part 91
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · April 6, 2018
- Flight plan
- Unknown
- 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
- 36
- Injuries
- None
- Certificate
- Commercial
- Airplane ratings
- Single-engine land
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- August 19, 2016
- Seat
- Right
- Restraint
- 3-point
- Flight hours
- 12,882 total · 9,558 in this make and model · 12,371 as pilot in command · 374 in the last 90 days · 47 in the last 30 days · 7 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 10° at 12 knots, gusting 21
- Visibility
- 10 statute miles
- Lowest ceiling
- 2,300 ft broken
- Temperature
- 70 °F, dew point 59 °F
- Altimeter
- 30.11 inHg
- Observed at
- KECU, 22 nm away
Docket · 2
The files NTSB released with the investigation on July 31, 2018, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.3 MB 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.