PIGEON FORGE, Tenn. — A preliminary report on a helicopter crash that killed the pilot and four people sightseeing near the Great Smoky Mountains National Park has found indications the tail rotor may not have had power when it hit trees on the top of a ridge.

The report from the National Transportation Safety Board released Monday lists some of the initial findings of the investigation without speculating on the cause of last week’s crash.

The report found the Bell 206 had plenty of fuel and the weather was clear. The helicopter was current on inspections and had already gone on several flights that morning.

Another helicopter pilot in the area reported hearing no distress call, but an on-the-ground witness told investigators the helicopter “didn’t sound right” before the crash.