| Tail Number / N-Number | N4521 |
| Manufacturer | AUTEL ROBOTICS |
| Model | EVO II PRO |
| Manufacturer's Serial Number | HV5920322100 |
| Aircraft Type | Rotorcraft |
| Category | Land |
| Builder Certification | Not Type Certificated |
| Number of Seats | 0 seats |
| Weight Class | CLASS 4 (UAV up to 55 pounds gross take off weight) |
| Number of Engines | 4 engines |
| Type of Registrant | Government |
| Owner Name | U S DEPARTMENT OF ENERGY |
| Street | C/O OAK RIDGE NATIONAL LABORATORY PO BOX 2008 MS-6144 |
| City | OAK RIDGE |
| State | TN |
| Zip Code | 37831-6144 |
| Region | Central |
| County | Anderson County |
| Country | US |
| Fractional Ownership | No |
| Certificate Issue Date | 2021-09-21 |
| Last Action Date | 2021-09-21 |
| Expiration Date | 2028-09-30 |
| Status | Valid Registration |
| Mode S Code | 51276005 |
| Mode S Code Hex | A57C05 |
Deregistered Aircraft 1 of 1. This aircraft was previously assigned the N-number N4521.
| Tail Number / N-Number | N4521 |
| Manufacturer | WACO |
| Model | 10 |
| Manufacturer's Serial Number | G-1390 |
| Aircraft Type | Fixed wing single engine |
| Category | Land |
| Builder Certification | Type Certificated |
| Number of Seats | 3 seats |
| Weight Class | CLASS 1 (Up to 12,499 pounds gross take off weight) |
| Number of Engines | 1 engine |
| Average Cruising Speed | 111 miles per hour |
| Type of Registrant | Individual |
| Owner Name | RICHARD WARREN SEARS |
| Street | GEN DEL |
| City | GRAYS LAKE |
| State | IL |
| Zip Code | 60021 |
| Region | Great Lakes |
| County | Anderson County |
| Last Status | Valid Registration |
| Cancellation Date | 1931-01-06 |