A 19-year-old has died after the remote control helicopter he was controlling sliced off the top of his head in Brooklyn.
Roman Pirozek Jr suffered fatal injuries after the model helicopter spun out of control and came crashing to the ground while he was performing a trick.
The two feet blades then sliced off the top of his head and cut his throat in front of horrified onlookers, including his father.
Paramedics attempted to save his life, but he was pronounced dead at the scene.
Pirozek was reportedly an avid enthusiast of model helicopters. A YouTube account believed to have belonged to the 19-year-old shows him performing a series of elaborate stunts with a model helicopter.
Police said he was a graduate of the High School for Construction Trades, Engineering and Architecture in Queens, New York.
Tributes have been paid to Pirozek on his YouTube account. One user named Torry wrote: "The kid was a good pilot, so sorry to lose someone so talented due to any type of accident. All of his friends and family should be proud of him and his accomplishments.
A second person, Kerrie, added: "Rest in peace. Glad you were able to enjoy something you loved doing on your last day. Thoughts and prayers to your family."
A spokesman for the organisation that governs model aeronautics in the US said accidents involving model helicopters are very rare.
Richard Hanson, public relations director for the Academy of Model Aeronautics (AMA) - of which Pirzek was a member - recommend that pilots never come within 25 feet (7.6m) of a model aircraft in flight.