# N10721: 1933 Sioux COUPE 90-B

- Status: Valid registration
- Airframe: [Sioux COUPE 90-B](https://openairdocs.org/model/sioux-coupe-90-b) (registry code 8250106, 2 seats)
- Engine: [Warner SS40&50](https://openairdocs.org/engine/warner-ss40-50) (registry code 64503)
- Data sheets: [TCDS ATC 414](https://openairdocs.org/tcds/ATC%20414) (Sioux Aircraft Corporation) (OpenAirDocs)
- Serial number: 401
- Year built: 1933
- Type: Fixed wing single engine
- Engine type: Reciprocating
- Airworthiness: Standard, normal
- Airworthiness date: July 29, 1977
- Certificate issued: January 9, 2007
- Expires: April 30, 2029
- Mode S code: A0216D
- Registered owner: [Antique Preservation Association Of Greenfield](https://openairdocs.org/faa-owner/ANTIQUE%20PRESERVATION%20ASSOCIATION%20OF%20GREENFIELD)
- Location: [Greenfield, IA](https://openairdocs.org/faa-place/IA/Greenfield)
- Owner type: Corporation
- Owner's area on the map: 41.2945° N, 94.4050° W: Placed by OpenAirDocs at the center of ZIP code 50849, within about 6 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=10721
- Page: https://openairdocs.org/aircraft/N10721

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 (Sioux COUPE 90-B)

None in force.

### Matched by engine (Warner SS40&50)

None in force.

## Information bulletins (advisory)

None matched.

## NTSB investigations

None matched to N10721.

## FAA accident and incident reports

None matched to N10721.

## 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) (2)

Approved for this aircraft's airframe or engine model, in force first, then newest. The registry doesn't record which STCs an aircraft has; its records do.

### Approved for the airframe (Sioux COUPE 90-B)

- [STC SA04652CH](https://openairdocs.org/stc/SA04652CH): To allow use of 100R grade aviation fuel meeting Swift Fuel, LLC specification. Swift Fuels LLC
- [STC SA01757WI](https://openairdocs.org/stc/SA01757WI): To allow the use of UL91 or UL94 (minimum) grade aviation fuel. Swift Fuels LLC

## Related

- Other Sioux COUPE 90-B aircraft: https://openairdocs.org/model/sioux-coupe-90-b/aircraft.md
- The Warner SS40&50 engine: https://openairdocs.org/engine/warner-ss40-50.md

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