from tape 0910 local RIVER-91 flight of 3 climbing up to 5k VFR on ZDC UHF.Then mentions KNTU.
Which ZDC UHF freq was it?
Checking LiveATC there was a RIPPER 91 that checked on with Potomac Wooly* Sector at around 0920 (controller only), VFR at 8500 mentioned airwork around Hagerstown, multiple vectors around BWI arrivals then cleared direct Hagerstown, handed off to Potomac 338.250 around 0932.
*at the time Wooly was combined with other sectors.