DAL Controller described a runway incursion event when an aircraft crossed without clearance; the reporter listing non-standard phraseology as a contributing factor.

Report 1 | Narrative: Aircraft X exited Runway 31R at Taxiway A3 and wanted to go to an FBO on the other side of the runway. I told the aircraft to make a 180 and hold short of Runway 31R on the other side. The aircraft made the 180 and started to cross the runway. I saw the aircraft cross over the hold short line and I told him not to cross the runway and turn around and exit the runway. I was told that there was no lost of separation but it was a runway incursion. Recommendation; the phraseology used by me was unclear and confusing. I should practice what I preach as a OJTI and always use standard phraseology.

If I would have done that here; the runway incursion would not have occurred.

Report 1 | Synopsis: DAL Controller described a runway incursion event when an aircraft crossed without clearance; the reporter listing non-standard phraseology as a contributing factor.