The Cessna 525 CitationJet CJ1 N102PT was parked in a hangar at Augusta State Airport, ME (AUG) in the morning, at the pilot’s request. However, the airline that used the hangar needed to house a plane. Since they had priority, the Citation was taken out of the hangar about 16:30 and moved back to the ramp area. While the airplane was on the ramp, the weather condition had turned from light snow to freezing rain. The pilot and her passenger arrived at the airport about 17:15. About 1730, the airplane’s engines were started and the airplane was observed taxing. The FBO representative heard the pilot’s announcements over the radio in the FBO. He also noticed the airplane was not on the taxiway, but on the grass area on the south side of the asphalt taxiway. At that time the ground was covered with snow and ice. The FBO representative noted the pilot did not activate the airport’s taxi and runways lights via the common airport frequency radio channel. It was observed that the airplane taxied through a ditch, which was covered with ice and snow. The airplane’s engines were heard at a high rate of power about this time. It was later discovered that the airplane’s left main tire broke through the ice and became stuck in the ditch. The airplane continued on the grass area after the high engine power was heard. The FBO representative heard the pilot announce the wrong runway (runway 35) that she was planning to depart from. The FBO representative turned on the runway and taxi lights after hearing the incorrect runway announcement. The pilot later announced a change of departure from runway 35 to runway 17, while the airplane was observed back taxing on runway 26 onto taxiway “C”. About 17:45 the airplane took off from runway 17. After takeoff, the pilot contacted the Air Traffic Controller (ATC) and reported that she was at 1,000 feet, climbing to 10,000 feet. About one minute later, the pilot declared an emergency and stated, “We’ve got an attitude indicator failure”. About seven seconds later, the pilot announced over the frequency they were not certain which way they were turning. Radar contact was lost shortly after that. PROBABLE CAUSE: “The pilot’s spatial disorientation and subsequent failure to maintain airplane control.”