The pilot's actions have been in focus in the investigation into the crash of the Sikorsky S-76B helicopter outside Los Angeles into hilly terrain.
Pilot Ara Zobayan told air traffic controllers that his chopper was climbing out of heavy clouds when in fact it was descending immediately before slamming into a hillside near the town of Calabasas, the NTSB said in June.
The board said pilots can become confused about an aircraft's attitude and acceleration when they cannot see the sky or landscape around them, causing "spatial 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 in June. Zobayan was killed in the crash.
An NTSB board member told reporters in the days after the Jan. 26 crash that clouds and fog causing limited visibility in the foothills north of Los Angeles would likely be a key focus of the investigation.
The board said previously an examination of the helicopter's engines and rotors found no evidence of "catastrophic mechanical failure" that could explain why the airship would have plunged into the terrain.Bryant, 41, an 18-time National Basketball Association all-star with the Los Angeles Lakers, was traveling with his 13-year-old daughter, Gianna, two other girls and several friends to a youth basketball tournament at the time of the crash, which prompted an outpouring of shock and grief from sports fans worldwide.