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. Kelvin Kuo, AP

The final minutes of interaction between the pilot of the helicopter carrying Kobe Bryant and air traffic controllers did not indicate any cause for alarm – until the communication suddenly ceased.

That was a bad sign that within seconds turned into the worst possible outcome.

The NBA legend, his 13-year-old daughter and seven other people were killed in a Sunday morning crash outside Los Angeles that has left many questions, chief among them: Why were they flying in foggy conditions that prompted the police department to ground its helicopters?

That query quickly came to mind for Robert Ditchey, a longtime airplane pilot, aeronautical engineer and former airline executive who lives in Los Angeles. A team of investigators is looking into the reasons for the tragedy, but Ditchey said he suspected right away that weather was a factor, and the notion was reinforced when he found out the aircraft in question was a helicopter.

Show caption Hide caption This image taken from video on Monday, Jan. 27, 2020, and provided by the National Transportation Safety Board, shows part of the wreckage of a... This image taken from video on Monday, Jan. 27, 2020, and provided by the National Transportation Safety Board, shows part of the wreckage of a helicopter crash near Calabasas, Calif. The Sunday, Jan. 26 crash killed former NBA basketball player Kobe Bryant, his 13-year-old daughter, Gianna, and seven others. (James Anderson/National Transportation Safety Board via AP) ORG XMIT: NYDD306 AP

“This was totally avoidable, and on the part of some people I can go as far as to say irresponsible,’’ Ditchey said. “Here’s one of the most important people in the world who comes to a tragic end like this and you say, ‘Why? What the hell happened?’ ’’

In your inbox: Get Kobe Bryant updates. Sign up here.

Audio of the last four minutes of exchanges between pilot Ara Zobayan and air traffic controllers, which was captured by LiveATC.net and combined with flight data into a video on the YouTube channel VASAviation, provides only sparse clues.

Final exchange between air traffic controllers and pilot flying the Kobe Bryant helicopter Audio captured by LiveATC.net reveals the final exchanges between air traffic controllers and the pilot flying the Kobe Bryant helicopter that crashed. USA TODAY, Storyful

Zobayan requested and was granted permission to fly the Sikorsky S-76B helicopter under special visual flight rules, which he was licensed to do. He was an experienced pilot who had logged 8,200 flight hours by July.

As he transitioned from the air traffic controller in Burbank to the one in Van Nuys, Zobayan maintained his special VFR privileges while flying at 1,400 feet of elevation and staying close to freeways.

But when the Southern California controller took over communication and asked the pilot to identify himself, he heard nothing back.

Air traffic controller: “72EX, you’re following a 1200 code. So you’re requesting flight following?’’

Pilot: No response.

Air traffic controller: “72EX, where, say intentions.’’

Pilot: No response.

Air traffic controller: “72EX you’re still too low level for flight following at this time.’’

Pilot: No response.

In heavy fog and with no radio connection to the controller, which was likely blocked by the mountains and low altitude, the helicopter crashed into a hillside in Calabasas, near Malibu.

Ditchey said helicopters can operate in bad weather because they can fly low, just as long as they have reasonable visibility, which is defined as at least 1 mile. Even then, going at 120 mph, that gives the pilot only 30 seconds to avoid a large obstacle.

While most of Bryant’s flight appears to have gone on without major problems, Ditchey said the helicopter ran into trouble when visibility decreased in the area over the Los Angeles Zoo near Glendale.

“They’re in the fog, and you’re down hugging the ground trying to fly up the highway and barely able to see it,’’ Ditchey said. “He’s down only 100 feet or so above the ground. In that area of the San Fernando Valley you have mountains on either side of you … and the clouds have obscured them, and you don’t have that much room to maneuver.’’

Los Angeles County Sheriff Alex Villanueva said the precise conditions when the crash occurred are still under investigation, but he acknowledged there was “an issue with visibility and a low ceiling’’ on Sunday.

Kobe Bryant's helicopter spotted minutes before deadly crash Kobe Bryant's helicopter was spotted circling over Glendale, California just minutes before its fatal crash. USA TODAY, Storyful

Both his office and the Los Angeles Police Department, which has a reputation for making conservative decisions in these instances, opted to keep their helicopters on the ground.

A person who answered the phone at the LAPD’s Air Support Division and would only give his name as Chester said the pilots – who are also police officers – decide when it’s not safe enough to fly.

Ditchey said that when he was in the Navy, sometimes he would fly in zero-visibility conditions because it was a military necessity. But he questioned why anybody without such a pressing mission would hop on a helicopter in what he called “very scary conditions.’’

“The weather is not good enough for the police to fly,’’ Ditchey said. “Why should Kobe do it?’’

More on the shocking loss of Kobe Bryant

Here's more coverage from USA TODAY following Bryant's death.