# N478SX: 2004 Olson Harold D SONEX

- Status: Valid registration
- Airframe: [Olson Harold D SONEX](https://openairdocs.org/model/olson-harold-d-sonex) (registry code 05617FQ, 2 seats)
- Engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999)
- Serial number: 478SX
- Year built: 2004
- Type: Fixed wing single engine
- Engine type: Reciprocating
- Kit: Sonex Ltd SONEX
- Airworthiness: Experimental, amateur built
- Airworthiness date: July 7, 2004
- Certificate issued: February 7, 2025
- Expires: February 29, 2032
- Mode S code: A5E078
- Registered owner: [Hardy Trav D](https://openairdocs.org/faa-owner/HARDY%20TRAV%20D)
- Location: [Lake Mills, WI](https://openairdocs.org/faa-place/WI/Lake%20Mills)
- Owner type: Individual
- Owner's area on the map: 43.0795° N, 88.9161° W: Placed by OpenAirDocs at the center of ZIP code 53551, within about 4 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=478SX
- Page: https://openairdocs.org/aircraft/N478SX

From the FAA registry file of October 24, 2026. ADs below are matched by the registry's airframe and engine model codes. They may apply; each AD's applicability can narrow it by serial number, part number or installed equipment. This is not a compliance determination.

## ADs that may apply (OpenAirDocs): 0 in force

### Matched by airframe (Olson Harold D SONEX)

None in force.

### Matched by engine (Amateur-built UNKNOWN ENG)

None in force.

## Information bulletins (advisory)

None matched.

## NTSB investigations (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB CHI05CA032](https://openairdocs.org/ntsb/CHI05CA032), Nov 21, 2004: Olson Sonex (N478SX), Oconomowoc, WI, substantial damage. Probable cause: The loss of engine power due to a fatigue fracture of the crankshaft. An additional cause to the accident was the pilot/builder's failure to verify the dimensions of the shrink-fit crankshaft…

## FAA accident and incident reports (1)

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [Accident 20041121032159A](https://openairdocs.org/incident/20041121032159A), Nov 21, 2004: Amtr SONEX (N478SX), Oconomowoc, WI, Substantial damage. (-23) On November 21, 2004, at 1435 CST, an amateur built Sonex aircraft, volkswagen powered, N478SX registered to, built by and piloted by[privacy data…

## Service difficulty reports

None filed for this aircraft. Matched to this aircraft by N-number and event date, checked against the reported serial number, make and model.

## STCs that may be installed (OpenAirDocs)

None matched to this aircraft's models.

## Related

- Other Olson Harold D SONEX aircraft: https://openairdocs.org/model/olson-harold-d-sonex/aircraft.md
- The Amateur-built UNKNOWN ENG engine: https://openairdocs.org/engine/amateur-built-unknown-eng.md

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.