From personal experience, I know that you can in do this. I will say that the unit has to want you very badly, and it takes a minimum of six months to get it through all the wickets. Your unit will have to continually advocate for you throughout the six months to get your paperwork through each of the offices along the way. They have to convince every office along the way of why they need you instead of a non-retired guy. They can't even start the application process until you are actually retired. There are a couple of guys in my unit that are doing this, and are actively flying. They are a real bargain, because they are working for very little money. They lose retired pay on the days they work, so they are essentially working for about half pay. To tell you the truth, I'm amazed that they even bother with it.