CEN23LA130

NTSB accident investigation · Robinson Helicopter R44 · De Kalb, TX · March 11, 2023

Accident · Serious injuriesClass 3 · LimitedFinal report
Date
March 11, 2023, 15:30 local (21:30 UTC)
Place
De Kalb, TX · field
Injuries
1 serious, 1 minor, 2 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N4164TRobinson Helicopter R44
Defining event
Maneuvering-low-alt flying: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
FAA Flight Standards
Case key
106877

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 inability to maintain control of the helicopter due to his failure to maintain rotor speed. Contributing to the accident was the failure of the helicopter’s low rotor speed warning system.

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 flight was conducted to hunt feral hogs. The pilot reported that a group of hogs had entered a large field, and he lowered the collective to maneuver the helicopter closer. When he lowered the collective, he perceived a loss of engine and rotor speed. The helicopter immediately began to lose lift. Once the pilot realized that he could not recover the helicopter, he attempted a running (skid-on) landing. However, the landing skids got stuck in the muddy field, the helicopter rocked forward, and the main rotor blades struck the ground causing the aircraft to roll over. The pilot reported the low rotor speed warning did not activate when the rotor speed started to decay. He also stated that all required preflight checklists were complied with before the flight began and no anomalies were noted. A postrecovery examination was unremarkable with exception of the low rotor warning system, which was not operational at the time of the examination. Specifically, the warning system did not activate when the collective control was brought off the low pitch stop and increased to full travel. The reason for the failure of the low rotor warning system was not determined.

Factual narrative

On March 11, 2023, about 1530 central standard time, a Robinson Helicopter R-44, N4164T, was substantially damaged when it was involved in an accident near De Kalb, Texas. The pilot and one passenger were not injured, a second passenger sustained minor injuries, and a third passenger was seriously injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight. The flight was conducted to hunt feral hogs. The pilot reported that a group of hogs had entered a large field, and he lowered the collective to maneuver the helicopter closer. When he lowered the collective, he perceived a loss of engine and rotor speed. The helicopter immediately began to lose lift. Once the pilot realized that he could not recover the helicopter, he attempted a running (skid-on) landing. However, the landing skids got stuck in the muddy field, the helicopter rocked forward, and the main rotor blades struck the ground causing the aircraft to roll over. The pilot reported the low rotor speed warning did not activate when the rotor speed started to decay. He also stated that all required preflight checklists were complied with before the flight began and no anomalies were noted. The helicopter sustained damage to the fuselage, main rotor blades, and tail boom. The aft portion of the tail boom, with the tail rotor assembly attached, was separated from the remainder of the airframe. It was located adjacent to the fuselage at the accident site. Postrecovery airframe and engine examinations, which included an 8-minute engine run, did not reveal any evidence of an in-flight structural failure, a flight control malfunction, or an inability of the engine to produce rated power. Although, the separated portion of the tail boom and tail rotor assembly were present at the accident site, they were not with the wreckage when recovered. The postrecovery examinations were unremarkable with exception of the low rotor warning system, which was not operational at the time of the examination. Specifically, the warning system did not activate when the collective control was brought off the low pitch stop and increased to full travel. The low rotor warning indicator bulb illuminated, and the warning horn emitted an audible sound when electrical current was applied. The reason for the failure of the low rotor warning system was not determined.

Aircraft

Registration
N4164T
Reported as
Robinson Helicopter R44
Category
Helicopter
Serial number
1882
Built
2008
Airframe hours
2,065.3
Engine
Lycoming O-540-F1B5, 260 horsepower, reciprocating
Damage
Substantial damage
Flight
Aerial observation · Part 91
Operator
Hotel Sierra Aviation LLC, doing business as N/A
Registered owner
Hotel Sierra Aviation LLC
Airworthiness certificate
Standard, Normal
Last inspection
Annual · December 10, 2022 · 16.9 hours before
Departed
PVT · Haworth, OK
Destination
PVT · Haworth, OK
Airport
N/A · N/A
Equipment
ADS-B

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
38
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
November 2, 2022
Seat
Rear
Restraint
3-point
Flight hours
1,972 total · 355 in this make and model · 1,750 as pilot in command · 135 in the last 90 days · 70 in the last 30 days · 10 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
190° at 8 knots
Visibility
9 statute miles
Lowest ceiling
2,700 ft broken
Temperature
72 °F, dew point 63 °F
Altimeter
29.62 inHg
Observed at
KTXK, 31 nm away
METAR
METAR KTXK 112153Z 19008KT 9SM SCT020 BKN027 OVC036 22/17 A2962

Docket · 10

The files NTSB released with the investigation on January 2, 2025, on NTSB’s docket system: statements, records, photos and specialists’ reports. 96.6 MB in all.