Authorities say a pilot is dead after the crash of a small single-seat helicopter in a remote Nevada canyon about 75 miles north of Las Vegas.

Lincoln County Sheriff Kerry Lee tells The Associated Press a friend of the pilot witnessed the crash and summoned authorities about 10:30 a.m. Thursday.

Lee says the witness reported hearing an unusual “pop” sound before the experimental-style aircraft plunged to the ground about 12 miles east of Highway 93 off Alamo Canyon Road.

The sheriff says it appeared the pilot was from St. George, Utah. His name wasn’t immediately made public.

Federal Aviation Administration spokesman Ian Gregor in Hawthorne, California, said the FAA and National Transportation Safety Board will investigate.