| Tail Number / N-Number | N51UD |
| Manufacturer | TEXTRON AVIATION INC |
| Model | 172S |
| Year Built | 2017 |
| Manufacturer's Serial Number | 172S12088 |
| 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 | LYCOMING |
| Engine Model | IO-360-L2A |
| Engine Type | Reciprocating |
| Number of Engines | 1 engine |
| Horsepower | 180 hp (134 kW) |
| Type of Registrant | LLC |
| Owner Name | ALF IX LLC |
| Street | C/O RESIDCO 70 W MADISON ST STE 2200 |
| City | CHICAGO |
| State | IL |
| Zip Code | 60602-4383 |
| Region | Great Lakes |
| County | Cook County |
| Country | US |
| Fractional Ownership | No |
| Airworthiness Classification | Standard |
| Airworthiness Date | 2017-10-30 |
| Certificate Issue Date | 2022-11-03 |
| Last Action Date | 2022-11-03 |
| Expiration Date | 2029-11-30 |
| Status | Valid Registration |
| Mode S Code | 51460334 |
| Mode S Code Hex | A660DC |
Deregistered Aircraft 1 of 1. This aircraft was previously assigned the N-number N51UD.
| Tail Number / N-Number | N51UD |
| Manufacturer | RICHARDSON ROGER |
| Model | MUSTANG |
| Manufacturer's Serial Number | 001 |
| Aircraft Type | Fixed wing single engine |
| Category | Land |
| Builder Certification | Not Type Certificated |
| Number of Seats | 2 seats |
| Weight Class | CLASS 1 (Up to 12,499 pounds gross take off weight) |
| Number of Engines | 1 engine |
| Type of Registrant | Individual |
| Owner Name | RICHARDSON ROGER D |
| Street | 3015 DAMASCUS CHURCH RD |
| City | CHAPEL HILL |
| State | NC |
| Zip Code | 27516-8052 |
| County | Cook County |
| Country | US |
| Certificate Issue Date | 1998-03-07 |
| Last Action Date | 1998-03-07 |
| Last Status | Valid Registration |
| Cancellation Date | 1999-03-02 |