Illusion blamed for crash reports

Police say an optical illusion was to blame for mysterious reports of a plane crashing off Darwin.

Authorities began looking for the plane on Sunday night and continued the search today but no trace of the aircraft could be found.

The mystery was solved by mid-morning when police went to the site of the witness reports.

The appearance of homes in the distance bore a striking similarity to a light plane very low to the ground.

"Even the search and rescue coordinator said it bears a striking resemblance to an aircraft," a Northern Territory police spokesman said.

"At a certain point on a coastal road, two structures meld together. That, together with the poor visibility last night, and cars on the road causing the light to flicker made it appear there was a plane."

The alarm was raised on Sunday by a woman standing on a jetty at Nightcliff.

She said she saw a small plane, similar to a Cessna, go down near the mangroves and other witnesses soon phoned in with similar reports.

The search, co-ordinated by the Australian Maritime Safety Authority, involved the CareFlight helicopter.

- AAP