LONDON, Sept 6 (Reuters) - The trustees of two BAE Systems pensions schemes have appointed Goldman Sachs Asset Management to manage 23 billion pounds ($28.88 billion) in defined benefit pension scheme assets, the fund manager said on Wednesday.

The mandate for BAE Systems Pension Scheme and BAE Systems Executive Pension Scheme is the largest outsourced chief investment officer appointment in Britain to date, GSAM said in a statement.

Pension funds are looking at ways to cut costs by outsourcing parts of their business.

($1 = 0.7964 pounds) (Reporting by Carolyn Cohn; editing by Jason Neely)