In 1981 the US Navy selected a modified version of the BAe Hawk trainer as the aircraft component of its T45 Training System. In May 1986 an engineering development contract was awarded to McDonnell Douglas (now Boeing), as the US prime contractor, with BAE Systems (formerly BAe) the principal subcontractor. Two versions were proposed: a wet T-45A outfitted for carrier borne operation and a dry T-45B restricted to land-based training and dummy carrier landing practice; the latter version was dropped.
The T-45 is based on the airframe of the basic Hawk Mk 60, but features a new forward fuselage deepened to house a new twin-wheel nose gear, redesigned main gear units, a taller fin and tailplane of increased span, a single ventral fin, fuselage side-mounted airbrakes, an arrester hook and small fins ahead of and below the tailplanes. The T-45 also has full-span leading-edge slats plus US Navy standard cockpit instrumentation and radios.
The three prototypes T-45s were delivered to the US Navy in October 1990. The first production T-45A made its maiden flight on 16 December 1991 and initial carrier qualifications began in the same month.
Plans to re-engine the T-45 with an American-built powerplant have been mooted; the Allied-Signal F124 turbofan was flight-tested in September 1997, without the modification proceeding further. Incorporated from the 84th production machine, the T-45C upgrade adds a much improved digital glass Cockpit 21 with two multi-function displays; this is being retrofitted to earlier aircraft. The original total of 268 T-45s was later trimmed to 197 Goshawks. Since the introduction of the T-45, the training task is being accomplished with 25 per cent fewer flying hours using 42 per cent fewer aircraft and 46 per cent fewer personnel.