Chorus Aviation, of Halifax, has won a contract to do heavy maintenance of an eastern European airline. Air Baltic will fly its 12 Next Generation Bombardier Q400s to Halifax to have the work done. Jazz Technical Services will perform the maintenance. It’s a division of Jazz Aviation LP, which has long experience with the Dash-8 line of aircraft and operates dozens of examples of various generations of them across the country. Financial terms of the deal were not released.