Northrop Grumman has opted to design a brand new aircraft for the US Air Force’s T-X trainer programme rather than a modified version of the BAE Systems Hawk it had planned to pitch.

Northrop has delegated the design work to Scaled Composites subsidiary, which is responsible for revolutionary aerospace innovations like the SpaceShipOne commercial space ship. Development of the new aircraft is apparently well along. Northrop says it will fly by the end of 2015.

“The Hawk is a tremendous airplane,” says Northrop spokesman Bryce McDevitt. “However we decided as a team to offer a new design as the US Air Force continued to mature their requirements.”

“The aircraft has been purpose designed for the Air Force” using advanced design and prototyping techniques, he says.

In July, Northrop took lead in offering an advanced version of BAE’s Hawk 128/T2 flown by the UK Royal Air Force. Rolls-Royce and L-3 Link Simulation and training also were on board for that effort. Those relationships are not necessarily severed as a result of Northop’s unilateral move, McDevitt says. Discussions are ongoing as to whether BAE will provide the training system for the Scaled Composites-designed aircraft. L-3 will supply the ground-based training system.

“We are currently in discussion with BAE about putting their training system onto our aircraft,” McDevitt says. “BAE remains a strategic partner, as does L-3.”

T-X will replace the Northrop T-38C Talon, which the air force says will be insufficient to train pilots for fifth-generation aircraft like the Lockheed F-22 Raptor and F-35 Lightning II. The T-38 entered service in 1961 and the airframes average 45 years old, the air force says.

The air force laid out a funding schedule for the advanced trainer replacement programme in its 2016 budget submission to Congress. The spending plan sets aside $11.4 million in fiscal 2016, then rises to $12 million in FY2017, $107 million in FY2018, $262 million in 2019 and $275 million in 2020.

A request for proposals is expected by the end of FY2016 with a milestone B engineering and manufacturing development contract award by fiscal 2018, according to air force budget documents.

The air force plans to buy up to 350 T-X trainers. Northrop’s move widens the already crowded field of contenders by at least one, depending on whether BAE decides to go it alone with Hawk.

General Dynamics and Alenia Aermacchi are promoting a ‘T-100’ version of the latter’s M-346, while Lockheed Martin is offering the T-50 developed jointly with Korea Aerospace Industries. Boeing and Saab are teamed on an all-new trainer design.