The pilot of the small plane that crashed into Beijing's tallest skyscraper last week had long suffered from anxiety and even discussed "ending his life" in his diaries, investigators said on Thursday.
The two-seat plane crashed into the over 100-floor headquarters building of the state-owned conglomerate CITIC Group on June 26, prompting the immediate evacuation of a large number of people working there.
The pilot was killed and 13 others injured in the incident. None of the injured is in a life-threatening condition, according to an official statement.
The pilot, identified only by his surname Liu, was a 66-year-old Beijing resident, according to the investigation released by the Chaoyang district government of Beijing on Thursday. The pilot was a divorcee and a freelance worker who lived alone.
He obtained a sport pilot licence in 2021 and a private pilot licence in 2024.
He took off in an Aurora SA60L, a single-engine two-seat light sport aircraft, from a general aviation airport in the eastern district of Pinggu located in Beijing's outskirts, in the afternoon.
"Liu first carried out an accompanied flight before taking off alone. During the solo flight, he left the designated operating area and lost contact with the airport before the aircraft hit the skyscraper," the statement said.
He had long-term insomnia and anxiety, and his diary contained repeated references to ending his life, it added.
The incident sparked security concerns as the building was located in the city's busy business district, not far from the Great Hall of People and Zhongnanhai, the well-protected residential compound housing top leaders of China.
All posts and photos about the crash were quickly removed from Chinese social media by the censors.
Flying any light sport aircraft in Beijing requires stringent approval from both the Civil Aviation Administration of China and the People's Liberation Army Air Force.
Last month, Beijing enacted sweeping regulations on its airspace, effectively banning casual recreational flying and consumer drones. All outdoor flights require prior government and air traffic approval.
"The incident was determined to be a case of endangering public safety caused by personal reasons," the district government said, the Hong Kong-based South China Morning Post reported.
However, the statement by the district government did not explain how the aircraft was able to travel from Pinggu district into one of the most sensitive and densely populated areas of the Chinese capital, the Post report said.
Just as it did a day after the crash, the district did not name the building in its statement on Thursday, referring to it as a skyscraper near the East Third Ring Road.
At 528 metres (1,732 feet), Citic Tower, also known as China Zun, is the tallest in the capital. The collision triggered an evacuation and sent debris falling onto streets and green spaces around the landmark building.
Flight schools across China said this week they had been told to suspend training and undergo safety inspections following the incident.