A year after the helicopter crash that killed basketball superstar Kobe Bryant, his youngest daughter and nine other people, NTSB published their findings.
The pilot of the helicopter had probably become disorientated amid fog, US safety investigators have said.
The helicopter smashed into a hillside near Calabasas, California, on 26 January 2020.
Pilot Ara Zobayan was among the dead.
Investigators also said Zobayan may have felt “self-induced pressure” to complete the flight for Bryant.
In its official finding, the NTSB said the main cause of the crash was most likely the pilot’s decision to keep flying in inclement conditions, “which resulted in the pilot’s spatial disorientation and loss of control”.
During the flight, Zobayan told air traffic controllers the helicopter was climbing out of heavy cloud when it was actually descending.
“This manoeuvre is consistent with the pilot experiencing spatial disorientation in limited visibility conditions,” said NTSB chairman Robert Sumwalt.
“We are talking about spatial disorientation where literally the pilot may not know which way is up or down, whether he or she is leaning left or right.”
The NTSB added that “inadequate review and oversight” of safety management processes by the helicopter charter company, Island Express, may have also contributed to the crash.
However, the board did not find that the Sikorsky S-76B had experienced any mechanical problems. The helicopter was not required to have “black box” recorders, which capture flight data and voices in the cockpit, and was not carrying any.
Zobayan violated federal rules and went against his own flight training by flying into thick clouds, safety officials said.