The RR Turbomeca Adour engine in the Hawk goes back to 1968. There are dozens of high-bypass lightweight turbofans developed in the last few years by several manufacturers that could have been selected to power a modern twin-engine trainer. For whatever reason, the Navy bought an old design airplane powered by a single old design engine, and did so at a horrendous budget cost. I think it was a horrible decision for which no one is being held accountable.