Amateur-built SWEARINGEN SX300 accident near Milford, Iowa, November 10, 2010
On November 10, 2010 at about 7:53 pm local time, a amateur-built SWEARINGEN SX300, registered N3ZX, was substantially damaged in an accident during enroute (cruise) near Milford, Iowa (Spencer Municipal airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of control for undetermined reasons.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 10, 2010 · about 7:53 pm local time
- Place
- Milford, Iowa · Spencer Municipal · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SWEARINGEN SX300
- Registration
- N3ZX · no longer on the register · serial 25
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The accident occurred during the instrument rated pilot's return flight home after an avionics upgrade, including the installation of flat panel flight displays. The pilot conducted a test flight the day prior to the accident flight with only minor discrepancies noted. There was no record of a preflight weather briefing associated with the accident flight. Radar track data showed the accident airplane on a southwest course at 8,600 feet mean sea level (msl). About 15 minutes prior to the accident, the airplane made a course adjustment to the west, before returning to a southwest course. During this time, the aircraft began a descent to 7,000 feet msl. The final radar data point was located about 1 mile southeast of the accident site. Witnesses reported hearing an airplane flying in a southwest direction. About 2 minutes later, they heard the sound of the engine increase, followed by a "big boom" and then nothing. The accident site was located in an open agricultural field. A postaccident examination of the wreckage did not reveal any anomalies consistent with a preimpact failure or malfunction. Weather data indicated the presence of an overcast cloud layer at 2,300 feet above ground level (agl), with additional cloud layer(s) between 4,000 feet msl and 8,500 feet msl, in the vicinity of the accident site.
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
- VFR encounter with IMC during enroute (cruise)
- Loss of control in flight during enroute (cruise) defining event
- Collision with terrain or object (not controlled flight into terrain) during enroute (cruise)
The NTSB's findings
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 3,160 hours in all
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Last inspection: condition inspection, April 20, 2009
- Maximum gross weight: 2,400 lb
- Seats: 2
- Landing gear: retractable
- Engine: Lycoming IO-540 SER (piston); 0 hours total
The flight
- Departed from: LVN Minneapolis MN at 6:40 pm
- Destination: HRX Hereford TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 220° at 6 knots
- Visibility: 6 statute miles
- Sky: overcast at 2,300 ft
- Temperature: 55°F (13°C), dew point 50°F (10°C)
- Altimeter: 29.78 inHg
- Observation at 7:53 pm from SPW, 10 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.