BAE in sole control of defence software firm.
The UK company, joint contractor for the pounds 2.9bn aircraft carriers project predicted to bring thousands of jobs to Tyneside, already owns half of Aerosystems International, whose designs are used on the Eurofighter and Tornado planes, as well as ships and submarines.
Engineering group GKN is selling its 50pc stake in the venture, which employs most of its 400 staff in the UK, to focus on its core aviation business.
Software by the Yeovil-based business allows planes and ships to plan their routes and communicate with each other.
It was formed in 1985 as a joint venture between Westland helicopters and software services company Cap Scientific.
BAE Systems said it would continue to operate as normal and become part of its customer solutions and support business. A spokesman described the move as a "positive" step and said BAE aimed to grow the business in the future. It also has sites in York and Worcester.
Redditch-based GKN, which makes parts for the car and aerospace industries, said the proceeds from the sale would be used to reduce short-term debt.