HALF MOON BAY -- Authorities believe the human remains found Tuesday in incinerated plane wreckage may belong to a pilot missing since taking off from Half Moon Bay Airport.

But the damage to the plane and remains discovered on a bluff about a mile north of Pillar Point Harbor and less than a mile west of the airport is so severe neither could immediately be identified, said San Mateo County Sheriff's Lt. Larry Schumaker.

Authorities have been looking for the missing Aeropro CZ A240 single engine plane registered to Andrew Hayden, 75, of Punta Gorda, Fl., since Monday. It took off from the airport around 5:50 a.m. en route to Tucson, Ariz.

When the plane didn't arrive, the pilot's wife reported him missing. Attempts to reach the Hayden family were unsuccessful Tuesday.

A San Mateo County park ranger discovered the wreckage around 11:35 a.m. while hunting for the vanished plane. County and FAA investigators were still working at the scene Tuesday night.

The craft came to rest among short brush in a broad dip on a coastal bluff and appeared to be headed east, in the direction of the airport. It was about 300 yards from the ocean.

There was little left of the plane except for a bare metal skeleton and what appeared to be an orange and white tail wing. The Aeropro CZ A240 has an aluminum frame that is covered by a polyfiber fabric.

The Coast Guard launched both a sea and air search for the missing plane but found nothing.

Staff writer Eric Kurhi contributed to this report. Contact Joshua Melvin at 650-348-4335. Follow him at Twitter.com/melvinreport.