An unmarked utility wire that was not shown on a navigation chart caused a DEA helicopter to crash last July in Breathitt County, according to the National Transportation Safety Board (NTSB).
The helicopter clipped the wire before crashing in the Evanston community.
The pilot and a state trooper on board the chopper were injured in the crash.
The two were on a DEA mission to spot illegal marijuana patches.
The NTSB report said after the helicopter clipped the wire, the pilot tried an emergency descent, but had limited control.
The helicopter hit the ground and caught fire.
The wire stretched between two ridges and once served a coal mine that is now closed, according to the NTSB.
The helicopter was equipped with blades designed to cut wires, but it hit the wire at the level of the main rotor head, above the top cutter, as it flew an estimated 500-feet above the valley floor, according to the NTSB report.