The plane that crashed last month in Cumberland County, killing a father and son, was making “unusual” sounds, according to a preliminary report from the National Transportation Safety Board.

The report says the plane was flying just three to four feet above the ground when it "aggressively" pulled up in an effort to clear some power lines. It then crashed.

Kristofer Noone, 24, and John Noone, 67, were identified as the victims. State police said that the single-engine plane crashed on Parvin Mill Road in Upper Deerfield Township.

The FAA says that the plane was a Champion Aeronca 7AC.