A 19-year-old man playing with a remote control helicopter in Brooklyn lost control of it while trying to perform a trick, sliced off the top of his own head and died Thursday afternoon, law enforcement officials said.

The helicopter enthusiast and his father were in Calvert Vaux Park at Shore Parkway and Bay 44th Street in Gravesend. Witnesses told detectives the teen, identified as Roman Pirozek Jr., was performing a trick with the model helicopter when something went wrong, and the aircraft boomeranged and sliced the top of his head, according to law enforcement officials.

Pirozek also sheared off part of his shoulder, officials said. He was killed instantly.

"I'll never forget it," said a shocked young witness. "It was scary."

Pirozek's father, Roman Pirozek Sr., broke down in tears as he returned to his Woodhaven, Queens home Thursday night. He declined to speak to reporters.

Neighbor Ralph Maisonett said, "It is the worst nightmare, to watch your son die."

Pirozek's neighbors said he worked at Kennedy Airport and was a world-recognized flyer who choreographed routines with the model helicopters.

Just days ago, he posted on his Facebook page that it was a "great day for flying."

Pirozek was a member of the Seaview Rotary Wings, a Brooklyn-based club for model helicopter enthusiasts, of which his father is also the vice president. The two of them flew model helicopters almost every weekend, sometimes traveling to competitions.

"It was their big hobby, and it's just very tragic to see and think about it," said neighbor Ken Marchisella.

"It's just an unreal event, that someone that young, that full of life, enjoying something, is gone," said family friend Dino Spadaccini. "It's an unbelievable tragedy."

Pirozek also had a YouTube page that documented his model helicopter flights.

"Every moment he had off from work or school, he'd be at the field with his friends," Spadaccini said.

Pirozek graduated in 2012 from the High School for Construction, Engineering and Architecture in Queens, according to his Facebook page.

No permits are necessary to operate RC helicopters, but it's recommended that hobbyists take extensive lessons before flying one, according to Dennis D'Annunzio, an expert with the company Rotomotion, which specializes in making and designing such helicopters.

When the proper precautions are followed, he says accidents are rare.

"People might burn themselves on a hot muffler or nick themselves on a blade but I've never heard of anything this tragic before," he told NBC 4 New York.

MORE NEW YORK-AREA STORIES: