Federal investigators say the pilot of a small plane thought he had enough room to pass another plane low and to the left when they collided fatally over San Francisco Bay last month.
In a preliminary report, the NTSB says the pilot of the vintage Hawker Sea Fury heard a thump and realized he had collided with the Cessna.
He had been in radio contact with the Cessna's pilot indicating he wanted to pass.
The pilot of the Cessna died.
He has been identified as 33-year-old David Everett Plumb, of Rocklin, California.