Amateur-built SKYBOLT accident near Smithfield, North Carolina, April 8, 1997
On April 8, 1997 at about 8:30 pm local time, a amateur-built SKYBOLT, registered N4TZ, was substantially damaged in an accident near Smithfield, North Carolina (Johnston County airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Installation by a student mechanic of a counterweight retaining washer that did not meet engine manufacturers specifications resulting in partial separation of the counterweight, failure of the No.5 connecting rod adjacent to the counterweight, and seizure of the engine. Contributing to the accident was improper supervision of the student mechanic by aviation school personnel.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 8, 1997 · about 8:30 pm local time
- Place
- Smithfield, North Carolina · Johnston County · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SKYBOLT
- Registration
- N4TZ · registry record · serial 003
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The engine failed and seized as the flight approached the airport for landing. During a forced landing in a field the aircraft nosed over. Post crash examination of the engine showed a counterweight retaining clip, washer, and pivot pin had separated allowing the counterweight to move around on the remaining pivot pin. The counterweight struck the No. 5 piston connecting rod causing it to fail and seize the engine. The counterweight retaining washer was found to have been ground and to not meet the manufacturers specified dimensions. Two pieces of the washer had separated. The engine had been taken by the owner to a community college aircraft maintenance school for overhaul. The engine was returned and installed on the aircraft 83 flight hours before failure. No logbook records were found to show the engine had been overhauled. Representatives of the aircraft maintenance school stated the work performed on the engine was a repair not an overhaul and that the original counterweight retaining washers and clips had been reused.
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: private
- Ratings: single-engine land
- Flight time: 450 hours in all; 450 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: rear
The aircraft
- Airframe total time: 285 hours
- Last inspection: annual inspection, April 1, 1997; 15 hours since
- Maximum gross weight: 900 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-540-A1D5 (piston); 0 hours total
The flight
- Departed from: RBW Walterboro SC at 6:00 pm
- Destination: JNX
- Flight plan: none
- Runway 21, 5,500 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 250° at 5 knots
- Visibility: 10 statute miles
- Sky: scat at 20,000 ft
- Temperature: 66°F (19°C), dew point 28°F (-2°C)
- Altimeter: 30.00 inHg
- Observation at 8:51 pm from RDU, 30 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.