| Tail Number / N-Number | N231NU |
| Manufacturer | MOONEY AIRCRAFT CORP. |
| Model | M20K |
| Year Built | 1980 |
| Manufacturer's Serial Number | 25-0331 |
| Aircraft Type | Fixed wing single engine |
| Category | Land |
| Builder Certification | Type Certificated |
| Number of Seats | 4 seats |
| Weight Class | CLASS 1 (Up to 12,499 pounds gross take off weight) |
| Engine Manufacturer | CONT MOTOR |
| Engine Model | TSIO-360 SER |
| Engine Type | Reciprocating |
| Number of Engines | 1 engine |
| Horsepower | 225 hp (168 kW) |
| Type of Registrant | Individual |
| Owner Name | MCMILLAN KEITH A |
| Street | 3413 N CRAMER ST |
| City | MILWAUKEE |
| State | WI |
| Zip Code | 53211-2816 |
| Region | Great Lakes |
| County | Milwaukee County |
| Country | US |
| Fractional Ownership | No |
| Airworthiness Classification | Standard |
| Airworthiness Date | 1980-02-21 |
| Certificate Issue Date | 2012-12-06 |
| Last Action Date | 2021-07-23 |
| Expiration Date | 2028-12-31 |
| Status | Valid Registration |
| Mode S Code | 50406566 |
| Mode S Code Hex | A20D76 |