The 25 new helicopters will replace the base’s 21 aging UH-1N Hueys. The additional four aircraft will allow the base to execute continuation of government operations and distinguished visitor transport mission requirements without augmenting support units.

https://www.af.mil/News/Article-Display/Article/3054990/new-mh-139-grey-wolves-will-go-to-joint-base-andrews/ DoD News