Investigators say a high-speed descent led to a landing gear collapse that caused a Delta Air Lines plane to flip upside down in Toronto in February.

According to a preliminary report, the Delta Air Lines plane that landed belly-up at Toronto’s Pearson International Airport last month was descending at a high rate of speed as its landing gear collapsed,

A warning system on the Delta Air Lines flight that crashed at Pearson airport last month sent an alert indicating a high rate of descent less than three seconds before the plane touched down, according to a preliminary report.