Facing pressure to fly two sick people to the mainland, billionaire coal tycoon Christopher Cline’s helicopter pilots took off from his Bahamas home illegally and within seconds became disoriented before slamming into the sea, investigators concluded.

Cline, founder of St. Louis-based coal miner Foresight Energy LP, his daughter Kameron and five others died on July 4, 2019, after less than 90 seconds of chaos-plagued flight, the U.S. National Transportation Safety Board said.

It is the second time in recent months that NTSB investigators cited almost identical factors in the fatal crash of a copter carrying a high-profile passenger. Basketball legend Kobe Bryant’s helicopter went down near Los Angeles in 2020 under similar circumstances after his pilot continued the flight despite deteriorating weather, most likely due to “self-induced pressure,” the NTSB said.

The lead pilot, described by NTSB as a “friend and confidant” of Cline’s, tilted the nose of the helicopter down almost immediately after lifting off, apparently sensing he was climbing when he was actually falling, the NTSB said in its final report. Investigators concluded he was suffering a well-known phenomenon known as “somatogravic illusion,” which was also cited in the Bryant crash.

The crash occurred even though a copilot on the flight correctly diagnosed the problem. About nine seconds before impact, copilot Geoff Painter said, “this is exactly what happened” in a 2014 crash on a similar Agusta AW139 model in the U.K., according to a recording of the cockpit recovered after the crash.

Pilot David Jude didn’t respond, “likely due to his continued confusion about the helicopter’s position in space and his misunderstanding of the information on the helicopter’s flight instruments,” the NTSB said.

Flying without being able to see the horizon can be difficult in helicopters. Cline’s aircraft took off at 1:52 a.m. on a moonless night. Once it left the Big Grand Cay heliport, there would have been no lights or visual references, the NTSB said in the report dated May 27.

Cline had asked for the flight to transport ill passengers to a hospital in Florida, the NTSB said. They were identified as Kameron and her friend, according to news reports.

Jude had difficulty controlling the helicopter almost as soon as he took off, and the two pilots were confused and didn’t communicate well. At one point, he announced they were at 300 feet (91 meters) altitude when they were actually only 78 feet above the water.

“We’re not,” Painter responded.

“That’s what it says over here,” Jude said.

Bahama’s aviation law prohibits such nighttime flights in which pilots don’t use autopilots, according to the NTSB report.

This article was provided by Bloomberg News.