Two small planes that collided over Corona last week, killing five people, did not try to avoid one another before the crash, federal investigators said in a preliminary report Thursday.

The National Transportation Safety Board report cited a witness who saw both aircraft cruising toward each other for at least five seconds before the collision, but noticed neither pilot tried to maneuver out of harm's way.

That scenario could mean that the pilots of the Cessna 150 and Cessna 172 didn't see each other.

"There is no evidence to indicate that this was anything but an accident," said NTSB investigator William Pollack.

The report did not place blame on either pilot in the Jan. 20 crash.

Two people in each plane were killed, along with a fifth person who was struck by aircraft parts that fell through the roof of an auto dealership about 40 miles southeast of Los Angeles.

The collision occurred about a mile south of Corona Municipal Airport, which doesn't have a manned control tower. The report said the Cessna 150 was headed east on approach to the airport and the Cessna 172 was traveling north at the time of the collision.

Without the aid of air traffic controllers, pilots are supposed to use visual flight rules when there are clear conditions. Pilots are responsible for their own safety, making sure they steer clear from aircraft and other potential hazards.

The investigation will take several more months, with a final report expected sometime by the end of the year, Pollack said.