The pilot of a U.S. Marine Corps reconnaissance airplane missing from Camp Pendleton since Thursday has been identified as Capt. Sergio R. Vivaldi, 29, of Port Chester, N.Y., Marine officials said Monday.
Vivaldi and observer 1st Lt. Joel H. Piehl, 31, of Bismark, N.D., have been missing since their OV-10A Bronco aircraft failed to return to the San Diego County base at 2:30 p.m. Thursday after a training mission.
As many as 28 aircraft from the Marine Corps Air Station in Tustin and Camp Pendleton have been searching for the craft in desert and mountain areas as far east as Phoenix and as far north as Las Vegas. The plane is an olive-colored, twin-engine turboprop.
Searchers spent another unsuccessful day Monday looking for the crew.
El Toro Marine base spokesman Lt. Gene C. Browne said the military is relying on civilian reports to direct the search.
"We're concentrating search efforts based on valid sightings," Browne said.
As of Monday, the Marines had received 19 calls from people who recalled seeing the plane as it flew overhead, Browne said. The sightings were concentrated in the Southern California mountain ranges, including the Big Bear, San Gorgonio and San Jacinto mountain areas.
Browne said the disappearance of a military plane for this long a time in Southern California is unprecedented for the Marines.
"We usually find them after a couple of hours," he said. "It's still a complete unknown (as to what happened)."
Piehl's sister, Linda Wolski, said Monday that he is an expert at desert survival who has trained infantry troops on what to do if lost in the desert.
"We have a lot of hope he'll be found soon," Wolski said.
Efforts to reach Vivaldi's family were unsuccessful Monday.
Civilians who may have seen the observation plane between 11:30 a.m. and 2:30 p.m. Thursday are asked to call the El Toro Marine base at (714) 726-2512.
Staff writer Jim Carlton contributed to this report.