Amateur-built SONERAI-I accident near Davenport, Iowa, June 23, 1991
On June 23, 1991 at about 8:48 pm local time, a amateur-built SONERAI-I, registered N4227N, was destroyed in an accident near Davenport, Iowa (Davenport Muni airport). It was a flight of an unrecorded kind 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
FAILURE OF THE WING SPAR STRAPS, AS THE AIRCRAFT WAS BEING MANEUVERED AROUND A PYLON IN AN AIR RACE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 23, 1991 · about 8:48 pm local time
- Place
- Davenport, Iowa · Davenport Muni · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SONERAI-I
- Registration
- N4227N · no longer on the register · serial 210
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PLT WAS PARTICIPATING IN A PYLON AIR RACE FOR FORMULA V RACERS. ABT HALF WAY THRU THE RACE, AS HE WAS MNVRG PAST THE #2 PYLON, THE LEFT WING BGN TO SEPARATE. THE WING THEN FOLDED OVR THE TOP OF THE ACFT. THE WING & PIECES OF THE CANOPY FELL TO THE GND. AS THE WING SEPD, THE ACFT BGN A VIOLENT ROLL & FLWD A TRAJECTORY PATH TO THE GND. INV REVEALED THE INNER PORTION OF EACH WING WAS DESIGNED WITH BOX SPAR CONSTRUCTION, SECURED TO A FUSELAGE CARRY-THRU CONFIGURATION. THE OUTER WING SPARS CONSISTED OF A SERIES OF UPPER & LOWER STRAPS. THESE WERE SECURED TO A SHEET METAL WEB WITH RIVETS. THE 4 LOWER SPAR STRAPS HAD FAILED; 2 HAD FAILED AT THE 1ST RIVET HOLE OUTBOARD OF THE BOX SPAR CONFIGURATION; ONE FAILED AT THE 1ST BOLT HOLE NEAR THE OUTBOARD END OF THE BOX SPAR & THE 4TH FAILED FLUSH WITH THE OUTBOARD END OF THE BOX SPAR.
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
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,000 hours in all; 100 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 750 lb
- Seats: 1
- Landing gear: fixed
- Engine: Volkswagen CONVERSION (piston); 0 hours total
The flight
- Departed from: DVN at 8:43 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 130° at 7 knots
- Visibility: 8 statute miles
- Sky: scat
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Observation at 9:05 pm from DVN, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.