| Tail Number / N-Number | N521RM |
| Manufacturer | CESSNA |
| Model | 421C |
| Year Built | 1977 |
| Manufacturer's Serial Number | 421C0335 |
| Aircraft Type | Fixed wing multi engine |
| Category | Land |
| Builder Certification | Type Certificated |
| Number of Seats | 8 seats |
| Weight Class | CLASS 1 (Up to 12,499 pounds gross take off weight) |
| Engine Manufacturer | CONT MOTOR |
| Engine Model | GTSI0-520-F-K |
| Engine Type | Reciprocating |
| Number of Engines | 2 engines |
| Horsepower per Engine | 435 hp (325 kW) |
| Total Horsepower | 870 hp (649 kW) |
| Average Cruising Speed | 90 miles per hour |
| Type of Registrant | LLC |
| Owner Name | G&W AVIATION LLC |
| Street | 3341 CR 122 |
| City | PARADISE |
| State | TX |
| Zip Code | 76073 |
| Region | Southwestern |
| County | Wise County |
| Country | US |
| Fractional Ownership | No |
| Airworthiness Classification | Standard |
| Airworthiness Date | 1977-08-09 |
| Certificate Issue Date | 2021-07-21 |
| Last Action Date | 2021-07-21 |
| Expiration Date | 2028-07-31 |
| Status | Valid Registration |
| Mode S Code | 51507050 |
| Mode S Code Hex | A68E28 |