Kobe Bryant's helicopter pilot was most likely severely disoriented by fog seconds before slamming into a hillside in January -- that's what federal investigators are now saying.
In new documents released Wednesday ... NTSB officials say they have evidence showing Ara Zobayan thought he was ascending when the chopper was actually going downward.
In the docs, investigators claim moments before the crash ... Zobayan told air traffic control he was "climbing to four thousand," and air traffic control asked him what he intended to do once he got to that altitude.