Patria said it installed new avionics and cockpit display systems on the twin-seat trainer that Finland originally purchased from Switzerland in 2007 to supplement the air force's fleet of Hawk MK51/51As.
Five of the upgraded aircraft will be delivered to the air force this year and eight next year. In all, Patria is modernizing 18 of the planes under a contract signed in 2009.
The Hawk MK 66 was built by British Aerospace, the predecessor of BAE Systems. The plane is nearly 39 feet in length and has a wing span of 39.75 feet. Its maximum level of speed is 645 mph.
Patria said the upgrade design is based on modernization of the MK 51s, which the company performed earlier.
The MK 66 will be used by the Finnish air force's training wing in Kauhava.
Patria assembled the bulk of the Finnish air force's Hawk Mk 51s and has been maintaining and servicing Hawks since 1980, when the air force inducted the aircraft into service.