A shocking aviation incident occurred in China when a small aircraft flew into Beijing’s tallest skyscraper on Friday, sending debris raining down onto crowds of people below.

In footage of the incident circulating online, the building, the CITIC Tower, appeared to sustain minimal damage, with a small section of its glass curtain wall shattered. But the aircraft itself was all but obliterated, with chunks of it hurtling through the air, almost in slow motion.

In one video, the camera operator flees to avoid getting hit. It’s unclear how many pedestrians were injured by the debris, if any. One employee who worked at the CITIC Tower told the New York Times that he saw at least one woman with a head injury being taken away in an ambulance. The fate and identity of the pilot are also unknown.

Whether this was an accident or intentional has yet to be established. But it’s an especially shocking event to happen in China, which has some of the most tightly regulated airspace in the world. In its largest cities — and its capital Beijing especially — not even drones can be flown without first being registered with the government and then getting preapproval for a flight. 

Details so far are scant. According to the NYT’s reporting, the aircraft appeared to be a lightweight model with only two seats registered to the airline Shuangyue General Aviation. Data from the flight tracking website FlightRader indicates it took off from an airfield in Pinggu, an eastern Beijing district, before circling and then flying west. 

“This aircraft is normally used for pilot training east of Beijing,” Ian Petchenik, a spokesman for FlightRadar, told the NYT. He added this was “out of character” with those types of flights, adding: “I don’t think we can rule anything out at this point.”

The crash occurred around 6 pm local time. By late evening police had cordoned off the entire block, the Financial Times reports, with multiple police vehicles and firetrucks.

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