CNN  — 

The helicopter that crashed over the weekend in California killing nine people, including NBA legend Kobe Bryant, dropped more than 2,000 feet a minute and was in one piece until impact into a hillside, a National Transportation Safety Board member said Tuesday.

The helicopter was at 2,300 feet in the air when it lost communication Sunday morning with air traffic control, the NTSB said. The pilot said he was climbing to a higher altitude to avoid a cloud layer. That last contact was around 9:45 a.m. Sunday. The first 911 call came in two minutes later, Los Angeles County Sheriff Alex Villanueva said.

Parts of the helicopter were found scattered at the crash site, which stretched 500 to 600 feet, the NTSB said.

As the NTSB wrapped up their recovery operations Tuesday at the crash site, investigators are working to determine the cause of the crash. NTSB board member Jennifer Homendy said the helicopter did not have a terrain awareness and warning system, which provides the pilot with information about the terrain.

She said the NTSB has recommended that similar helicopters be equipped with the safety feature following a fatal crash in Galveston, Texas that killed 10 people in 2004. The Federal Aviation Administration failed to implement the recommendation, Homendy said.

She said the helicopter missed clearing a mountain by 20 to 30 feet.

“The descent rate for the helicopter was over 2,000 feet a minute, so we know that this was a high energy impact crash,” Homendy said.

She added: “This is a pretty steep descent at high speed. So it wouldn’t be a normal landing speed.”

According to Homendy, “preliminary information is that the helicopter was in one piece when it impacted the terrain.”

As investigators scour for clues, 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, Homendy said Monday. But when air traffic control asked him what he planned to do, there was no response.

Visibility was so low Sunday morning that the Los Angeles Police Department had decided to ground its helicopters that morning.

A photo from the Los Angeles County Sheriff's Department shows foggy conditions at the site of the crash Sunday.

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.

The other six passengers included two of Gianna’s teammates with their parents and an assistant girls basketball coach. The pilot, Zobayan, was also killed.

The LA County Department of Medical Examiner-Coroner announced Tuesday that four of the nine bodies recovered, including Kobe Bryant, were officially identified through the use of fingerprints. Investigators are still working on identifying the five remaining bodies.

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.

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. She said he had 1,250 hours of flight time on the S-76 helicopter.

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 an earlier 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