CALABASAS, Calif. -- The National Transportation Safety Board released devastating video Tuesday showing the aftermath of the crash that killed nine people, including NBA legend Kobe Bryant and his daughter.
Video shows investigators combing through the debris left behind in the Sunday crash. NTSB investigators are expected to stay at the site for several days as they work to learn more about the crash.
In the meantime, the pilot's last words with air traffic control illustrate a foggy scene in the sky.
Pilot Ara Zobayan said he was climbing to avoid a cloud layer, the NTSB said. But when air traffic control asked him what he planned to do, there was no response, NTSB board member Jennifer Homendy said.
Visibility was so low Sunday morning that the Los Angeles Police Department had decided to ground its helicopters that morning.
But it's still not certain what caused the helicopter to crash, killing parents, children, and one of the greatest athletes of all time.
Bryant, 41, and his daughter Gianna, 13, were heading to a basketball game in Thousand Oaks, where he was expected to coach and she was expected to play.
All eight passengers killed in the crash were children or parents. They included two of Gianna's teammates with their parents and an assistant girls basketball coach. The pilot, Zobayan, was also killed.
How the pilot got special permission to fly
Moments before the crash, the pilot received SVFR clearance -- or special visual flight rules clearance, according to audio recordings between the pilot and air traffic control.
SVFR clearance allows a pilot to fly in weather conditions worse than those allowed for regular visual flight rules.
Pilots sometimes request SVFR clearance mid-flight if weather conditions suddenly change, CNN transportation analyst Peter Goelz said. Those granted permission typically keep closer contact with air traffic control.
While SVFR clearance is "pretty normal," Goelz said, "it's not something that's often recommended."
After the pilot requested special permission to fly through the area, the helicopter circled for 12 minutes until air traffic control approved SVFR clearance, Homendy said.
When the pilot flew into the Burbank and Van Nuys airspace at 1,400 feet, he requested radar assistance to avoid traffic, Homendy said. But air traffic control said the helicopter was too low to be able to get that assistance.
Zobayan said he was going to climb higher, and air traffic controllers responded. But they never heard back. Radar data indicated the helicopter climbed 2,300 feet and began a left descending turn, Homendy said.
The last radar contact was around 9:45 a.m. Sunday. The helicopter crashed two minutes later.
Homendy said investigators will look into whether Zobayan should have been granted SVFR clearance.
Pilot had thousands of hours of flight time
Zobayan was experienced and had 8,200 hours of flight time as of July 2019, Homendy said.
He had been working with Island Express Helicopters, which owned and operated the Sikorsky S-76B.
"We are working closely with the National Transportation Safety Board to investigate the cause of the accident and we are grateful to the first responders and local authorities," Island Express said in a written statement.
NTSB investigators are looking at pilot records, weather information, ATC communications and the wreckage as part of the investigation.
The chopper is reliable, safe and capable, aviation analyst Miles O'Brien told CNN.
"It's a workhorse," O'Brien said. "It's the flying Lincoln Town Car for executives. This is what corporate helicopter aviation is built on -- on this Sikorsky."
Helicopter broke into pieces at impact
The impact of the crash broke the helicopter into pieces, creating a debris field of about 500 to 600 feet, Homendy said. The crash created a crater at about 1,085 feet above sea level, she said.
"There is (an) impact area on one of the hills and a piece of the tail is down the hill, on the left side of the hill," she said. "The fuselage is over on the other side of that hill, and then the main rotor is about 100 yards beyond that.""
Investigators initially struggled to access the site of the wreckage due to the difficult terrain, Los Angeles County Sheriff Alex Villanueva said. Eventually, authorities bulldozed the road to get to the location.
Complicating their access, mourners flooded the area to get a glimpse of the scene.
An emergency ordinance was issued, making it a misdemeanor to unlawfully access the site, Villanueva said Monday. Deputies are patrolling the rugged terrain on horseback, he said.
Three young girls were on board
Among the victims were three teenage girls on their way to the basketball game.
Alyssa Altobelli, who was Gianna's teammate, was on the helicopter with her father, Orange Coast College (OCC) baseball coach John Altobelli and her mother, Keri Altobelli.
Her father would routinely travel with her to attend her games, OCC assistant coach Ron La Ruffa said.
Payton Chester and her mother Sarah Chester were also killed in the crash, Payton's grandmother Cathy Chester wrote on Facebook.
"While the world mourns the loss of a dynamic athlete and humanitarian, I mourn the loss of two people just as important ... their impact was just as meaningful, their loss will be just as keenly felt, and our hearts are just as broken," Todd Schmidt, a former principal at the elementary school Payton once attended, wrote in a Facebook post.
Christina Mauser, an assistant girls basketball coach for a private school in Corona del Mar, California, was also killed in the crash.
"My kids and I are devastated," her husband, Matt Mauser, wrote on Facebook. "We lost our beautiful wife and mom."
Fans worldwide turn grief into aid
Now fans and companies are carrying on Bryant's legacy of philanthropy.
StubHub announced all fees on tickets sold for Friday's game between the Los Angeles Lakers and the Portland Trail Blazers in Los Angeles will be donated to the Kobe and Vanessa Bryant Family Foundation.
In Japan, a Red Cross fundraising video featuring Bryant is getting shared widely once again.
The video was produced to support victims of the 2011 earthquake and tsunami, which killed about 20,000 people and left many more homeless. "The NBA family starts with the people of Japan, the survivors of the earthquake and the Pacific tsunami," Bryant said.