OCEANSIDE–A pilot was killed and his passenger seriously injured when their single-engine small plane crashed into a hillside in Oceanside.

Approximately around 7:14 a.m., Oceanside police dispatchers received a call from an individual who reportedly saw the plane wreckage on the hillside, located off eastbound State Route 76 and east of Canyon Drive, according to Oceanside police spokesman Tom Bussey.

When police and fire department personnel arrived, they found the crash site. There were two male occupants in the aircraft. The pilot was deceased and the passenger sustained major injuries. Firefighters removed the passenger from the plane and airlifted him to Scripps La Jolla.

The passenger told rescuers the crash occurred approximately 5 hours earlier. The exact cause of the crash is unknown.

Highway 76 Eastbound from Canyon Drive to Bennet Road was closed until the aircraft was removed.

A number of agencies responded to the incident including Oceanside Fire Department, Vista Fire Department, Camp Pendleton Fire/Rescue, FAA and NTSB.

The crash is under investigation.