LOS ANGELES — Flying aboard a luxury helicopter with a veteran pilot at the controls, Kobe Bryant and his seven fellow passengers should have had few worries.

Their Sikorsky S-76B that would whisk them roughly 90 miles from Orange to Ventura Counties, crossing over the heart of Los Angeles, was "like the Cadillac Escalade" of choppers, recalled Kurt Deetz, a former pilot for Bryant. That model is a sleek craft with dual engines equipped with "all the bells and whistles," Deetz said.

Yet it lacked a key safety feature: a terrain awareness and warning system, TAWS, a National Transportation Safety Board official said Tuesday. The NTSB had recommended it be required on large passenger-carrying choppers after a Texas crash in 2004, but that never happened.

The remains of the retired NBA superstar, his 13-year-old daughter and the others have now been recovered. Their relatives have been notified, Los Angeles County authorities said.

Fans Mourn the loss of NBA legend Kobe Bryant outside of the Staples Center in Los Angeles.

NTSB investigators finished collecting evidence Tuesday, hauling wreckage out on helicopters in large white bags to be trucked away from the 600-foot debris field. While the cause is it yet to be determined, the thick, gray clouds that obscured much of the area Sunday are being scrutinized as a possible cause.

A body is carried from the scene of a helicopter crash that killed former NBA basketball player Kobe Bryant, his daughter and several others in Calabasas, Calif., Sunday, Jan. 26, 2020. (AP Photo/Kelvin Kuo)

"We are not just focusing on weather. We are going to take a broad look at everything around this accident," said Jennifer Homendy, the NTSB board member leading the investigation.

Key questions include:

• Was pilot Ara Zobayan flying too fast, more than 150 miles per hour, and too low in moments before the crash?

• Had he become lost?

• Did the helicopter, despite all of the safety features built into it, incur a mechanical failure?

Besides TAWS, Bryant's copter also lacked "black boxes" that could aid investigators, Homendy said. NTSB had also previously recommended flight data and cockpit recorders for helicopters, to no avail, Homendy said. Investigators, however, have radar tracking and communications with air traffic controllers.

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More: Questions emerge about why Kobe Bryant's helicopter was flying in 'very scary conditions'

From that, they know that the helicopter was flying using visual reference, tracking along the Southern California's maze of freeways beneath them at about 1,400 feet.

Near Burbank, California, about halfway through the journey, Zobayan was granted permission to fly at less than what is considered minimum visibility -- three miles with a ceiling of 1,000 feet. The copter fell below levels needed for radar tracking.

It rose to 2,300 feet then began a left descending turn before barreling into a steep mountain slope at a high rate of speed, impacting intact with such force that it left a crater and scattered wreckage over a wide area. The copter came to rest 1,085 feet above sea level, about 30 feet below the crest of the hill where it struck.

Kobe Bryant helicopter circled Glendale before deadly crash

Deetz had piloted the helicopter from 2015 to mid-2017 along with Zobayan while working with helicopter's owner, Island Express Holding. Though it was old, built in 1991, it held a special place in the fleet.

“It’s my favorite, it’s fast and reliable. It’s what I call ‘bulletproof,’” Deetz said during a telephone interview on Tuesday.

It was Bryant’s favorite, too, he said.

He had previously flown in a Sikorsky S-76A copter, an earlier version of the chopper that lacked air conditioning and other amenities. When the helicopter company got the newer model, Bryant switched.

“The difference was like comparing a Toyota Corolla with something like a Cadillac Escalade,” said Deetz. It had AC, it was quiet and big. “He really liked it, and it became his choice.”

More: Final exchange between air traffic controllers and pilot flying the Kobe Bryant helicopter

Deetz said the copter was capable of carrying 10, and was configured for a pilot and co-pilot in the cockpit, partitioned by a curtain from up to eight passengers in the back of the aircraft.

The copter typically underwent regular maintenance after every 25 hours of flight time, with other work done as needed. Island Express was “very good about maintenance,” and would have a mechanic check the aircraft if a pilot noticed potential safety problems during mandatory pre-flight checks, said Deetz.

“It’s a very reliable aircraft,” he said. “It wasn’t a maintenance hog.”

Developed to haul crews for the offshore oil and industry, the S-76 series became a favorite for executive transport. President Donald Trump's company has owned several. With twin engines that enhance safety, a Los Angeles Times analysis found it has the second-lowest rate of fatal accidents per 100,000 flight hours at 0.22. Only the Airbus H130 topped it.

During his NBA career, Bryant typically flew in the copter several times per week for Lakers games and practices, as well as family events, said Deetz. The frequency of his flights dropped after retiring from basketball.

Deetz recalled Zobayan as a good pilot and co-worker who “always had a smile on his face and was a funny guy.”

“We butted heads sometimes like people do with co-workers, but nothing serious,” said Deetz.

Zobayan lived in Huntington Beach, California, an Orange County city that cultivates its image as "Surf City." Federal Aviation Administration records show Zobayan was rated for helicopter flying both in visual and instrument conditions when he got his commercial pilot license in 2007. He was rated as a helicopter flight and ground instructor for instrument flying.

He logged 8,200 hours of flight time, including 1,256 in the S-76, Homendy said.

Zobayan found his passion and professional life’s calling from a sightseeing flight over the Grand Canyon, according to the company where he trained as a pilot.

He came to Group 3 Aviation at the Van Nuys Airport in California after that 1998 experience, company owners Peter and Claudia Lowry wrote in a Facebook posting.

He always “remained cool, calm and collected," a grieving friend, Jared Yochim, recalled in a posting on Facebook. “Ara was an incredible pilot, instructor pilot, charter pilot and truly a great man. He was not your typical egotistical helicopter pilot like most of us honestly are.” Plus, he was “always good for a laugh.”

But even good pilots can make mistakes, though it is still to early to know if Zobayan did.

Zoey Tur, a veteran news helicopter pilot with more than 10,000 hours of flying time, said pilots of corporate helicopters, often seated directly with passengers, may be hesitant to admit they are lost or headed into a dicey situation. They may fear a celebrity passenger will ask not to fly with them again or a FAA penalty.

"You have to be strong enough to tell the VIP on board 'I can't do it,'" she said. "If you get caught in weather conditions, it's maybe a little bit of a confession."

More: Kobe Bryant tragedy is latest in sports world's long, tragic history with aviation crashes

Tur believes Zobayan appears to have lost his way in the fog and was flying too fast for the conditions. Absent a mechanical issue, "this is clear pilot error," she said. Zobayan could have asked to convert from flying visually to proceeding only on instruments. Air traffic controllers could have directed the helicopter to the closest airport. He could have set down in a vacant field, even if it meant facing FAA penalties, and called limos for his passengers.

And even if he hadn't of those actions, he could have slowed as fog became a bigger issue, Tur said.

"The pilot was lost in the fog and instead of slowing down, he, for some reason, accelerated," Tur said.

The NTSB said a preliminary cause of the crash will take time. For now, those who knew Zobayan, Bryant and the other passengers can only grieve.

Deetz, who last flew Bryant in July 2017, said when he learned of the crash Sunday, including that the helicopter involved had the tail number N72EX, he said his first thought was a hope that Bryant was not on board.

“But then I found out what happened,” said Deetz. “It was surreal. I knew Ara. I knew Kobe, and I had flown his family. And now they’re gone.

Contributing: Nathan Bomey, Kristin Lam

This article originally appeared on USA TODAY: Kobe Bryant's body and others now recovered from crash site