Amateur-built HARTLINE KITFOX III accident near Marathon, Texas, May 2, 2018
On May 2, 2018 at about 4:00 pm local time, a 1991 amateur-built HARTLINE KITFOX III, registered N73BH, was substantially damaged in an accident during takeoff near Marathon, Texas (Stovall Ranch Airport). It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the flaperon hinge attachment point during takeoff, which resulted in a loss of airplane control. Contributing to the accident was the lack of reinforcement of the hinge attachment point in accordance with the manufacturer’s service bulletin.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 2, 2018 · about 4:00 pm local time
- Place
- Marathon, Texas · Stovall Ranch Airport · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built HARTLINE KITFOX III III, built 1991
- Registration
- N73BH · no longer on the register · serial 1000
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot and the passenger were departing on a local personal flight in the experimental amateur-built airplane. The pilot indicated that, during the takeoff climb, about 15 ft above the ground, the airplane violently rolled to the right. He applied full aileron and rudder opposite the direction of the roll, but the airplane continued to roll to the right, struck the ground with the right wing, and then impacted a tree. Postaccident examination of the airplane revealed that three of the four hinges connecting the right flaperon hanger rib were loose. The wooden material of the flaperon was found dry rotted where the hinges connected. The airplane had been flown about 3 hours in the 11 months before the accident. The airplane kit manufacturer had issued a service bulletin in 1991 that identified flaperon hanger rib failures on the model of the accident airplane. The service bulletin recommended the addition of an aluminum reinforcement on each flaperon hanger rib end. The accident airplane did not have the reinforcement installed and thus did not have the benefit of additional reinforcement in the attachment point area of the hinges.
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
- Flight control sys malf/fail during takeoff defining event
- Collision with terrain or object (not controlled flight into terrain) during takeoff
The NTSB's findings
- cause Aircraft › Aircraft systems › Flight control system › (general) › Failure
- factor Personnel issues › Task performance › Maintenance › Installation › Owner/builder
- Environmental issues › Physical environment › Object/animal/substance › Tree(s) › Contributed to outcome
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; multi-engine sea; single-engine land; single-engine sea; instrument: airplane
- Flight time: 20,000 hours in all; 130 in this make and model; 35 in the last 90 days; 29 in the last 30 days
- Last flight review: May 5, 2017
- Medical certificate: Sport Pilot
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 1,184.6 hours
- Last inspection: condition inspection, May 23, 2017; 3 hours since
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 912 (piston); 1,182 hours total
The flight
- Departed from: 6TX9 Marathon TX at 4:00 pm
- Destination: 6TX9 Marathon TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 230° at 21 knots, gusting 34
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 30°F (-1°C)
- Altimeter: 30.04 inHg
- Observation at 3:55 pm from KE38, 100 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on January 15, 2020. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 4 pages | View Download |
| 2 | Memorandum for the Record FAA Examination Summary CEN18LA157 | PDF, 1 page | View Download |
| 3 | Memorandum for the Record Airplane Owner Information Summary CEN18LA157 | PDF, 1 page | View Download |
| 4 | Manufacturer Service Bulletin No 9 September 12 1991 | PDF, 3 pages | View Download |
| 5 | Photo Array CEN18LA157 | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.