Amateur-built SONEX accident near Naples, Florida, May 26, 2013
On May 26, 2013 at about 3:30 pm local time, a 2004 amateur-built SONEX, registered N634SX, was substantially damaged in an accident during emergency descent near Naples, Florida (Marco Island Airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s failure to maintain airspeed during a forced landing, which resulted in an aerodynamic stall. Contributing to the accident was a partial loss of the noncertificated engine’s power for reasons that could not be determined because examination of the engine did not reveal any mechanical malfunctions or failures that would have precluded normal operation.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 26, 2013 · about 3:30 pm local time
- Place
- Naples, Florida · Marco Island Airport · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SONEX, built 2004
- Registration
- N634SX · no longer on the register · serial 0634
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
About 5 minutes after takeoff and at a cruise altitude of 2,000 feet above ground level, the engine lost oil pressure and partial power. The pilot was unable to maintain the airplane's altitude and flew toward a golf course to conduct a forced landing. During short final approach, he turned the airplane left to better align it with a fairway, but the airplane stalled and impacted a canal. The airplane was equipped with a noncertificated, modified automobile engine. Examination of the wreckage did not reveal any cracks in the engine case, oil residue in the engine compartment, or any abnormalities that would have accounted for the sudden loss of oil pressure and partial engine power.
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
- Loss of engine power (partial) during enroute (cruise)
- Aerodynamic stall/spin during emergency descent defining event
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Airspeed › Not attained/maintained
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- factor Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,360 hours in all; 20 in this make and model; 1 in the last 90 days; 1 in the last 30 days; 1,200 as pilot in command
- Last flight review: June 15, 2011
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 37 hours
- Last inspection: condition inspection, April 20, 2013; 3 hours since
- Maximum gross weight: 1,000 lb
- Seats: 2
- Landing gear: fixed
- Engine: Aerovee 2180 (piston); 37 hours total
The flight
- Departed from: APF Naples FL at 3:25 pm
- Destination: IMM Immokalee FL
- Flight plan: none
- Runway 17, 5,000 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 040° at 10 knots, gusting 15
- Visibility: 10 statute miles
- Sky: scat at 3,700 ft
- Temperature: 88°F (31°C), dew point 68°F (20°C)
- Altimeter: 30.12 inHg
- Observation at 3:53 pm from APF, 11 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
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.
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.