Preliminary data indicates that the Ukraine International Airlines’ passenger airplane that crashed in Tehran (Iran) on January 8 was returning to the airport from which it took off after encountering a technical problem. The Iranian Civil Aviation Organization announced this in a statement, Ukrainian News Agency reports. "The plane's trajectory indicates that the plane was initially heading westward, turning right due to a technical problem, and it was on its way back to the airport at the time of the crash," the statement said. Ali Abedzadeh, the head of Iran’s Civil Aviation Organization, said that the airplane’s flight recorders (black boxes) have been found and they have been handed over to accident investigators. According to him, both the Flight Data Recorder (FDR) and the cockpit voice recorder (CVR) were found with impact and fire damage, the memory units are available but show physical damage. Abedzadeh said that the preliminary accident investigation report stated that airplane climbed to 8,000 feet (about 2,439 meters) at 06:18 local time, when it disappeared from radar and later crashed. According to the statement, the pilot received no radio messages about unusual circumstances. According to eyewitness reports (people on the ground and the high-altitude flight crew who observed and reported the incident), the aircraft caught fire, crashed to the ground, and exploded. According to the statement, the accident site documentation shows that the airplane's first impact with the ground was in an amusement park area. In addition, Abedzadeh stated that the accident investigation team, in accordance with the standards set forth in annex 13 of the Chicago Convention, has invited all states recognized as interested parties by this document to send their representatives to participate in the crash investigation process and designate their own special teams. According to him, initial notification has been sent to Ukraine as the country of registration of the aircraft, the United States as the manufacturer, Sweden and Canada as the applicant countries whose nationals were in the aircraft. As Ukrainian News Agency earlier reported, a UIA passenger airplane crashed in Iran on January 8. All the passenger airplane’s passengers and crewmembers, including 11 Ukrainians, were killed. The Ukrainian National Security and Defense Council has set up an operational headquarters in connection with the plane crash.