FRA is my Home airport. UA uses gates in C and A still. There is a ton of changes going on at FRA. All LH USA flights depart from the upper A gates. (but at times they use a C gate) If you are a RCC member there is a LH Biz lounge that you will get access to. If you are *G you can use the Senator lounge. The C gates are getting a face lift, and this is why some UA flights depart from A. This has been going on for some time now..