Kobe Bryant’s widow has sued the owner of the helicopter that crashed in fog and killed the former basketball superstar and their 13-year-old daughter, as she publicly mourned their deaths in an emotional public ceremony.

The wrongful death lawsuit filed by Vanessa Bryant in Los Angeles Superior Court said the pilot was careless and negligent by flying in cloudy conditions on January 26 and should have aborted the flight that killed all nine people aboard.

The lawsuit names Island Express Helicopters and also targets pilot Ara Zobayan’s representative or successor, listed only as "Doe 1" until a name can be determined.

The company has yet to respond to the lawsuit.

Fans line up to get into the Staples Center to attend a public memorial for former Los Angeles Lakers star Kobe Bryant and his daughter. Credit: AP

The lawsuit claims Mr Zobayan was negligent in eight ways, including failing to properly assess the weather, flying into conditions he was not cleared for and failing to control the helicopter.

It was filed on the morning a public memorial service for Bryant, his daughter and all the victims, including Mr Zobayan, was held to a sold-out crowd at the Staples Centre, the arena where Bryant played most of his career for the Los Angeles Lakers.

Bryant, his daughter Gianna and six of their friends were on their way to a basketball tournament at his Mamba Sports Academy when the helicopter crashed.

Mr Zobayan, Bryant’s frequent pilot, had been trying to navigate in heavy fog that limited visibility to the point that the Los Angeles police and sheriff’s departments had grounded their helicopter fleets.

Fans carry posters of Kobe Bryant near the Staples Center. Credit: AP

Under the visual flight rules Mr Zobayan was following, he was required to see where he was going.

He had been cited by the Federal Aviation Administration in May 2015 for violating those rules by flying into reduced visibility air space, the lawsuit said.

In his last transmission, he told air traffic control that he was climbing to 4,000ft to get above the clouds.

He was 100ft short of breaking through the cloud cover when the helicopter banked left and plunged into a grassy hillside, according to the National Transportation Safety Board.

The NTSB has not concluded what caused the crash in Calabasas, on the outskirts of Los Angeles County, but said there was no sign of mechanical failure. A final report is not expected for a year or so.

The scene of the crash Credit: AP

Island Express issued a statement on January 30 saying the shock of the crash had prompted it to suspend services until it was appropriate for staff and customers.

Island Express has had at least three helicopter crashes since 1985, two of them fatal, according to the NTSB’s accident database.

All involved flights to or from the company’s main destination of Santa Catalina Island, about 20 miles off the southern California coast.