The investigation into the doomed Bahamas helicopter trip that killed billionaire tycoon Chris Cline could take years, according to a report.

It could take up to two years before authorities determine what sent the 15-passenger aircraft plunging into the waters off Grand Cay island around 2 a.m. July 4, the Sun Sentinel reported.

“We look to investigate the facts surrounding the accident. We look at three areas: human, the machine and the environment,” National Transportation Safety Board spokesman Eric Weiss said.

The wreckage has been recovered and moved to an unknown but secure site where US officials will take over the investigation.

“It’s in a secure location, protected from the weather, so nothing gets blown away or rusted. It’s evidence,” Weiss told the newspaper. “We don’t say where the evidence is.”

Flight and data recorders were also shipped from the Bahamas to the agency’s offices in Washington for analysis.

Authorities said they plan to release a preliminary report in two weeks on the crash, which killed all seven people on board.

The chopper was heading to a hospital in Fort Lauderdale for a medical emergency when it crashed shortly after taking off, officials said.

Among the victims was the coal magnate’s 22-year-old daughter, Kameron Cline; pilot Geoffrey Lee Painter, 52; and pal David Jude, 56.

They were killed alongside Kameron’s friends, Brittney Layne Searson, 21, Jillian Nicole Clark, 22, and Delaney Lee Wykle, 22.

With Post wires