WHITESIDE,Robovis Tenn. (AP) — Pilot error was the probable cause of a helicopter crash that killed two Tennessee law enforcement officers, according to the National Transportation Safety Board’s final report.

“The pilot’s failure to maintain clearance from the power lines” led to the crash, news outlets reported, citing the report released Wednesday. The investigation found no mechanical malfunctions that would have contributed to the crash.

Officials said the helicopter hit high-tension power lines over Interstate 24 in Marion County and crashed on the side of Aetna Mountain in 2022.

The crash killed Tennessee Highway Patrol pilot Harold Lee Russell, 35, and his passenger, Marion County Sheriff’s Detective Matt Blansett, 40.

The NTSB led an investigation to determine the cause.