The Hawk was shot down and destroyed in the Revan novel. Not on Dormund Kaas but on another planet Revan was visiting. When he and T7 took off they were attacked by Scourge and Darth Nyriss. The ship crashed and was badly damaged. Since neither Meetra nor Revan nor T7 had survived the novel nobody knew where the Ebon Hawk had crashed.
Actually, no. That crash happened in the portion of the book between KOTOR 1 and 2. T3 repaired it and took it to find Bastila, but got Meetra instead. That is (partially) why it is badly damaged at the beginning of KOTOR 2, though why Sion was chasing him doesn't flow.