US federal safety officials blamed the helicopter crash that killed basketball star Kobe Bryant and eight others last year on the pilot's decision to fly into thick clouds where he became disorientated.
The National Transportation Safety Board (NTSB) said poor visibility probably led pilot Ara Zobayan to become so disoriented in thick fog north of Los Angeles that he could not perceive up from down.
The five board members also said Mr Zobayan, who also died in the crash, ignored his training and violated federal regulations during the 40-minute flight.
The agency announced its findings during a four-hour hearing aimed at pinpointing probable causes of the tragedy – which led to widespread public mourning for the retired basketball star, launched several lawsuits and prompted state and federal legislation.
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, when the Sikorsky S-76 helicopter encountered thick fog in the San Fernando Valley on January 26th, 2020.
There was no sign of mechanical failure and the crash was believed to be an accident.
Investigators said they believed Mr 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 agency criticised Mr Zobayan's decision to fly into the clouds, saying Federal Aviation Administration standards require that pilots are able to see where they are going under what is called visual flight rules.
Board members, in a unanimous vote, also cited the self-induced pressure Mr Zobayan likely felt to finish the flight for his star client, whom he flew often, instead of landing at a nearby local airport when the weather became worse than he had expected.
Mr Zobayan also failed to file a back-up flight plan before departing.
"The closer you get to the destination, the more you think just maybe you can pull this off," NTSB vice-chairman Bruce Landsberg said.
The agency also faulted Island Express Helicopters Inc, which operated the aircraft, for inadequate review and oversight of safety matters.
Just before the crash, Mr Zobayan told flight controllers he was climbing in the helicopter and had nearly broken through the clouds.
But NTSB investigators said that the helicopter was in fact banking and beginning to descend quickly, investigators said.
The aircraft 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.
The impact caused a crater and scattered debris over an area the size of an American football field. The victims died immediately.
There were 184 aircraft crashes between 2010-2019 involving spatial disorientation, including 20 fatal helicopter crashes, the NTSB said.
NTSB member Michael Graham said Mr Zobayan ignored his training and added that that as long as helicopter pilots continue flying into clouds without relying on instruments, which requires a high level of training, "a certain percentage aren't going to come out alive".
“What part of cloud, when you’re on a visual flight rules programme, do pilots not understand?” Mr Landsberg added.
The helicopter did not have so-called “black box” recording devices, which were not required.
The NTSB is an independent federal agency that investigates transportation-related crashes but has no enforcement powers.
The others killed in the crash 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 team-mates. – AP