Investigators: Rotor came off before helicopter hit building near Salt Lake City, killing 2

SALT LAKE CITY – Safety inspectors say mechanics had worked on the main rotor of a helicopter and were taking it for a test flight when the rotor came off and the chopper crashed into a building near Salt Lake City.

The National Transportation Safety Board has released a brief preliminary report about the crash that killed two men Dec. 2.

The agency says the helicopter was registered to Native Range Capture Services in Elko, Nevada. The company captures wildlife so researchers can tag or transport the animals.

Inspectors say witnesses heard popping sounds before seeing the aircraft’s main rotor and the tail assembly come off. The helicopter then tumbled and hit a building in an industrial area of North Salt Lake.

The chopper’s owner says the mechanics were trying to check the rotor blades’ track and balance.