LOS ANGELES (Reuters) – The pilot of a helicopter that crashed in foothills near Los Angeles, killing basketball great Kobe Bryant, his daughter and all seven others on board, likely became disoriented in the fog, federal investigators said on Wednesday.

The National Transportation Safety Board report said pilot Ara Zobayan told air traffic controllers that his helicopter was climbing, when in fact it was descending shortly before slamming into a hillside outside the community of Calabasas on Jan. 26.

The NTSB said that pilots can become confused over an aircraft’s attitude and acceleration when they cannot see the sky or landscape around them, causing “spacial disorientation.”

“Without outside references or attention to the helicopter’s attitude display, the actual pitch and bank angles have the potential to be misperceived,” the NTSB said.

The findings came in a “public docket” released by the NTSB as it investigates the crash. The agency has not yet released its final report.