Robinson Helicopter Company R44 II accident near Marble Falls, Texas, July 9, 2023
On July 9, 2023 at about 2:47 pm local time, a 2006 Robinson Helicopter Company R44 II, registered N163RK, was substantially damaged in an accident during enroute near Marble Falls, Texas. It was an aerial observation flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
A total loss of engine power due to fuel contamination from an unknown source.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 9, 2023 · about 2:47 pm local time
- Place
- Marble Falls, Texas · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson Helicopter Company R44 II, built 2006
- Registration
- N163RK · registry record · serial 11120
- Damage
- Substantial damage
- Flight
- Aerial observation flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the helicopter was conducting an aerial observation flight when, about 250 ft above ground level (agl) and about 50 knots indicated airspeed, the engine lost total power. The pilot entered an autorotation, negotiated a powerline, and landed on a hill. During the landing, the helicopter rocked forward and aft, striking and substantially damaging the lower vertical stabilizer. Postaccident examination revealed water and a reddish-colored polyamide substance in the main fuel tank, auxiliary fuel tank, electric fuel pump, and gascolator. Further examination of the polyamide was inconclusive for a single known substance. The pilot reported that during the three-day mission, he refueled the helicopter at three different airports as well as his own personal fuel supply. Postaccident examination of the owner’s personal fuel supply and each of the airport’s fuel delivery systems did not reveal the presence of contamination. The circumstances of the accident are consistent with a total loss of engine power due to fuel contamination; however, the source of the contamination could not be determined based on the available information.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Autorotation Collision with terrain or object (not controlled flight into terrain)
- Fuel contamination during enroute defining event
The NTSB's findings
- Aircraft › Fluids/misc hardware › Fluids › Fuel › Fluid condition
- Aircraft › Aircraft systems › Fuel system › Fuel pumps › Damaged/degraded
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,080 hours in all; 1,603 in this make and model; 94 in the last 90 days; 34 in the last 30 days; 4,852 as pilot in command; 2,532 on instruments
- Last flight review: May 4, 2022
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
Other crew
- Medical certificate: None
- Seat: rgt
- Injury: no injuries
Passenger
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 5,590 hours
- Last inspection: annual inspection, June 16, 2023; 0 hours since
- Maximum gross weight: 2,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-540-AE1A5 (piston); 146 hours total
- Operator: Lone Star Aircraft Holdings LLC.
The flight
- Departed from: RYW Lago Vista TX at 2:41 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 170° at 5 knots
- Visibility: 10 statute miles
- Sky: scat at 8,000 ft
- Temperature: 100°F (38°C), dew point 61°F (16°C)
- Altimeter: 29.87 inHg
- Observation at 4:15 pm from KDZB, 6 miles away
Weather report (METAR): KDZB 092115Z AUTO 17005KT 10SM SCT080 38/16 A2987 RMK AO2 T03760164
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR23LA263.