Federal investigators are looking at human error as the cause of last week's deadly collision of two small planes over Sharonville.
The National Safety Transportation Board released its preliminary report Saturday.
Investigators say both aircraft were mechanically sound and the weather was good.
So they are focusing on possible miscommunication between the pilots.
David Woeste, Edward Hitchens and Niels Harpsoe died in the accident.
The full investigation by the NTSB of the collision could take more than a year.
