The January 2020 plane crash that killed NBA star Kobe Bryant, his daughter, and seven other passengers was caused by “spatial disorientation” by the pilot who was “legally prohibited” that day from flying into clouds, the U.S. National Transportation Safety Board said Tuesday.

In a press conference announcing the long-awaited conclusion of its investigation into the Jan. 26 crash, NTSB Chairman Robert Sumwalt revealed that pilot Ara Zobayan was “flying under visual flight orders or VFR which legally prohibited him from penetrating the clouds” but he continued onwards. To gain better visibility, Zobayan is believed to have piloted the helicopter to climb sharply upwards and most likely became disoriented while flying through the clouds. Sumwalt said Zobayan told air traffic controllers his helicopter was climbing out of heavy clouds—when in fact it was descending.

The Sikorsky S-76B helicopter eventually slammed into a hillside near Calabasas, killing the pilot and the nine passengers who were traveling to a youth basketball tournament.