LOS ANGELES — Federal safety officials on Tuesday blamed the helicopter crash that killed Kobe Bryant and eight others on board last year on the pilot's poor decision to fly into clouds where he became disoriented and plunged into a Southern California hillside.

The National Transportation Safety Board said the crash happened amid thick fog in the hills of the San Fernando Valley north of Los Angeles. The poor visibility probably led pilot Ara Zobayan to become disoriented and misperceive the angles at which he was descending and banking, the agency said.

Investigators said they believed Zobayan experienced a spatial disorientation known as "the leans," which occurs in the inner ear and causes pilots to believe they are flying aircraft straight and level when they are in fact banking.

The NTSB's long-awaited findings come after the Jan. 26, 2020 crash unleashed worldwide grief for the retired basketball star, launched several lawsuits and prompted state and federal legislation about crash site photos and safety devices.

The board members also criticized Island Express Helicopters Inc., which operated the aircraft, for inadequate review and oversight of safety issues.

Bryant, his 13-year-old daughter, Gianna, and six other passengers were flying from Orange County to a youth basketball tournament at his Mamba Sports Academy in Ventura County. 

The others killed were: Orange Coast College baseball coach John Altobelli; his wife, Keri, and their daughter Alyssa; Christina Mauser, who helped Bryant coach his daughter's basketball team; and Sarah Chester and her daughter Payton. Alyssa and Payton were Gianna's teammates.

Zobayan, an experienced pilot who often flew Bryant, had climbed sharply and nearly succeeded breaking through the fog and clouds when the helicopter made an abrupt left turn and plunged into grassy, oak studded hills in the city of Calabasas.

When it hit the ground, the Sikorsky S-76B helicopter was flying at about 184 mph (296 kph) and descending at a rate of more than 4000 feet (1,219 meters) per minute. 

Investigators believe Zobayan experienced a spatial disorientation known as "the leans," which occurs in the inner ear and causes pilots to believe they are flying the aircraft straight and level but are in fact banking.

The impact caused a crater and scattered debris over an area the size of a football field. The victims died immediately, according to autopsy reports.