| Tail Number / N-Number | N557HR |
| Manufacturer | JOHNSTON PHILIP |
| Model | HARMON ROCKET II |
| Year Built | 2005 |
| Manufacturer's Serial Number | 34 |
| 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) |
| Engine Manufacturer | LYCOMING |
| Engine Model | IO-540 SER |
| Engine Type | Reciprocating |
| Number of Engines | 1 engine |
| Horsepower | 300 hp (224 kW) |
| Kit Manufacturer | HARMON ROCKET LLC |
| Kit Model | HARMON ROCKET II |
| Type of Registrant | Individual |
| Owner Name | JOHNSTON PHILIP R |
| Street | 30197 FRONTERA DEL SUR |
| City | HIGHLAND |
| State | CA |
| Zip Code | 92346-5936 |
| Region | Western-Pacific |
| County | San Bernardino County |
| Country | US |
| Fractional Ownership | No |
| Airworthiness Classification | Experimental |
| Airworthiness Date | 2005-05-06 |
| Certificate Issue Date | 2005-04-29 |
| Last Action Date | 2023-01-14 |
| Expiration Date | 2030-03-31 |
| Status | Valid Registration |
| Mode S Code | 51615053 |
| Mode S Code Hex | A71A2B |