Here's What We Know About Kobe's Last Flight

Investigators work at the scene of the helicopter crash, where former NBA star Kobe Bryant and eight others died, including his 13-year-old daughter Gianna. (David McNew/Getty Images)

UPDATE:

6:05 p.m.: This article was updated with information from the National Transportation Safety Board's Tuesday afternoon news conference.

This article was originally published at 2:15 p.m.

Federal safety investigators said Tuesday the helicopter that was carrying Kobe Bryant and eight others was in "steep descent" before it crashed, and that the helicopter lacked an onboard safety net system that investigators had previously recommended be required for all similar aircraft.

Investigators said they will issue a preliminary report on Sunday's accident in 10 days, but the final report outlining the probable cause of the crash could take up to 18 months.

Here's what we know about the flight so far:

"STEEP DESCENT"

The helicopter was 2,300 feet above sea level when it lost communication with air traffic control. It then descended rapidly, at a rate of over 2,000 feet per minute, National Transportation Safety Board member Jennifer Homendy said.

"So we know that this was a high energy impact crash," she said.

Investigators said the helicopter's impact site was about 20 to 30 feet below the top of the hill, but stressed there were also higher hills in the canyon.

TERRAIN AWARENESS WARNING SYSTEM

Homendy said there was no terrain awareness and warning system (TAWS) on the helicopter. The NTSB had recommended in 2006 that all helicopters with capacity for six or more passengers be equipped with this type of warning system. The recommendation came after a 2004 helicopter accident near Galveston, Texas.

However, the Federal Aviation Administration did not implement the recommendation, Homendy said.

After investigating a helicopter crash in the Baltic Sea in 2005, the NTSB also recommended helicopters be equipped with a cockpit voice recorder and flight data recorder. But the FAA didn't accept that recommendation, either.

There was no "black box" on board, but investigators recovered an iPad and cell phone.

FLIGHT PATTERN

The helicopter left John Wayne Airport in Orange County shortly after 9 a.m. en route to a youth basketball tournament in Thousand Oaks. It traveled up the I-5 corridor before circling around the Burbank airport several times, waiting for air traffic controllers to clear it.

Once cleared, it continued northwest through the Van Nuys airspace and then west to follow the 101 corridor, crashing into a Calabasas hillside around 9:45 a.m.

The website Flightradar24 has an interactive map showing the flight's path.

You can see the flight pattern in motion here >>

'SPECIAL VISUAL FLIGHT RULES'

The pilot, who has been identified Ara Zoboyan, was given permission to fly through Burbank and Van Nuys' airspace, under what is known as "special visual flight rules," a kind of clearance for flying in low visibility. John Cox, an aviation safety expert, told LAist special visual flight rules are requested by helicopter pilots pretty routinely because they can fly slower and closer to the ground.

Homendy from the NTSB also said it was "very common" to fly under special visual flight rules.

The LAPD had grounded its helicopters Sunday morning because of low visibility, according to spokesman Josh Rubenstein. But Homendy said that's not an indication that conditions were unsafe for other helicopters to be flying, calling it an "apples to oranges" comparison. "Different helicopter, different operations," she said.

Investigators have yet to determine how much weather was a factor in the crash. Tom Anthony, director of the USC Aviation Safety and Security Program, says pilots can get disoriented in heavy fog.

"When you're in a cloud, you can lose spatial orientation," Anthony said. "Low clouds, low ceilings and lack of visibility, mountain obscuration, are all adverse weather conditions for flight."

'FLIGHT FOLLOWING'

After the pilot left the Van Nuys airspace, he asked an air traffic controller for what's known as "flight following." This means navigation help from the control tower to help cope with the low visibility. An air traffic controller told the pilot that the helicopter was flying too low to register on the radar and therefore too low to offer flight following.

LAST COMMUNICATION

According to investigators from the National Transportation Safety Board, the pilot told air traffic controllers that he was climbing to avoid a cloud layer shortly before the helicopter crashed into a hillside in Calabasas.

The NTSB's Homendy said Zoboyan had a "good amount of experience," with over 8,200 hours of flight time. The day before the accident, he flew from John Wayne to Camarillo, but the weather was clear and he took a more direct flight path, Homendy said.

THE HELICOPTER

This Feb. 1, 2018, photo shows the Sikorsky S-76B helicopter (N72EX) at Van Nuys Airport. The helicopter's exterior was later repainted. (Matt Hartman/AP)

The helicopter was a Sikorsky 76-B, a luxury helicopter popular with VIPs but also used for search and rescue and utility missions, like transporting people to oil rigs. The NTSB has recorded 53 accidents since 1979 involving Sikorsky S-76 helicopters, 12 of them fatal. Aircraft experts say the model is considered very safe.

"It's a real workhorse of a helicopter," Peter Goelz, former managing director of the NTSB, told KPCC's AirTalk. "It has a pretty good safety record."

The helicopter was owned by a company called Island Express Holding Corp. and news outlets have reported that Bryant used the copter — and Zobayan as a pilot — on many occasions.

WHAT'S NEXT?

NTSB investigators finished their work at the crash site Tuesday and turned it over to local authorities, Homendy said. They have begun to interview air traffic controllers and other witnesses and will continue with interviews over the next few days, she said.

Whenever the NTSB issues its final report, Homendy said it could also recommend new safety measures with the goal of preventing a similar accident in the future.

Jill Replogle contributed to this report.