TAMPA — A helicopter attempting to make an emergency landing crashed onto a busy street on Thursday, sending one of its rotors flying into a passing vehicle, killing a passenger, authorities said.

The crash took place at about 2:21 p.m. near the intersection of S 50th Street and Palm River Road. The blue Robinson R44 helicopter suffered catastrophic engine failure, said Hillsborough Sheriff Chad Chronister at a news conference held at the crash scene.

The helicopter was attempting to make a "hard landing," the sheriff said, when it struck a telephone pole. That caused one of the rotor blades to break off, fly across the street and strike a Chevrolet Silverado pickup truck that was traveling north on S 50th Street.

The severed rotor killed a passenger, the father of the driver.

Alejandro Bou-Colon said he saw the helicopter fall from the sky. He works at Top Choice Automobile Sales at 506 S 50th St., which is right next to the crash site.

He said it looked like the helicopter was trying to land on a patch of grass. Instead, it came down fast, hit the ground and started skidding across the roadway before hitting a pole. He said debris went flying everywhere.

The Sheriff's Office did not release the names of those involved in the deadly crash.

The pickup driver was also injured and taken to Tampa General Hospital for treatment. The sheriff did not say how seriously injured he was.

The helicopter pilot was taken to a local hospital to be treated for heat exhaustion and dehydration and may also have injured in the crash.

The unidentified pilot was "highly trained," the sheriff said. Chronister said the helicopter had just been serviced, passed several tests and was deemed to be functioning properly.

The sheriff said the helicopter was on its way to Sarasota when the pilot experienced engine failure.

When asked if the pilot handled the emergency landing the best possible way, Chronister said "depends who you ask."

"I'm sure the passenger of that truck probably doesn't feel that way right now ...," the sheriff said, but noted it could have been worse: "We have one death when it could've been more."

The National Transportation Safety Board will send investigators to the site to start examining the helicopter crash, Chronister said. The Florida Highway Patrol will investigate the death of the truck passenger.

"I'm not a flight investigator by any means," the sheriff said, "but I can say thank God nobody else was injured."

Times staff writer Tony Marrero contributed to this report. Contact McKenna Oxenden at moxenden@tampabay.com. Follow @mack_oxenden.