LOUISVILLE, Ky. (WDRB) -- We now know the cause of a helicopter crash last week near Pigeon Forge, Tenn., that killed five tourists.

An NTSB report says the helicopter likely suffered some mechanical damage before hitting a set of trees on a ridge in the Smoky Mountains.

The reports cites a witness nearby who reported seeing the helicopter flying unusually low, stating it "didn't sound right."

The witness said it sounded as if the helicopter "lost the rotor sound" after which he heard the engine go silent, "as if the pilot cut the power."

Another nearby witness reported hearing the impact and then seeing the crash site engulfed in flames.

The accident occurred on a tourist helicopter. All five occupants, including the pilot, died.

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