The doomed helicopter carrying coal magnate Chris Cline, his daughter and five others was in the air for only a minute before it spun out of control and crashed in the Bahamas, killing everyone on board, federal authorities said Wednesday.

A witness saw the ill-fated chopper lift off July 4 from Cline’s private Big Grand Cay island, climb between 40 to 50 feet and then spin left three to four times, according to a preliminary report by the National Transportation Safety Board.

The witness heard a “whoosh whoosh whoosh” sound and lost sight of the helicopter — and then heard it crash into the water.

Local reports have said the helicopter left in the middle of the night to take Cline’s 22-year-old daughter Kameron to a hospital in Fort Lauderdale after she got sick. The NTSB report said two people had fallen ill, but doesn’t name them.

The 17-seat August AW139 aircraft arrived to the island from Palm Beach International Airport between 1:30 and 1:45 a.m. and remained on the landing pad with the engines running, while the passengers boarded.

After about a minute in the air, the aircraft dropped and slammed into the water some 1.2 miles away from where it had taken off, the report said.

Relatives called authorities at 2:53 p.m. after realizing the helicopter never made it to Fort Lauderdale.

Local residents in the Bahamas found the chopper upside down in water 16-feet deep sometime between 4 and 5 p.m., the report said. It’s rotor blades were separated.

In addition to the billionaire and his daughter, the crash killed three of her friends, Brittney Layne Searson, 21, Jillian Nicole Clark, 22, and Delaney Lee Wykle, 22.

They had all been on the island to celebrate the Republican donor’s 61st birthday.

Pilot Geoffrey Lee Painter, 52, and copilot David Jude, 56, also died.

The preliminary report did not uncover the cause of the crash.

The full investigation into the crash could take up to two years, a NTBS spokesman said earlier this month.