SURABAYA, Indonesia (AP) -- With no sign of the missing AirAsia jetliner, dozens of ships and planes on Tuesday joined a widening international effort now covering huge swaths of Indonesian sea and land. A device that can detect underwater signals from the aircraft's black boxes was also on its way, more than two days after Flight 8501 vanished from radar.
The United States announced it was sending the USS Sampson destroyer, joining at least 30 ships, 15 aircraft and seven helicopters in the search for the jet carrying 162 people, said Indonesia's Search and Rescue Agency chief Henry Bambang Soelistyo.
A Chinese frigate was also on the way, while Singapore said it was sending two underwater beacon detectors to try to detect pings from the plane's all-important cockpit voice and flight data recorders. Malaysia, Australia and Thailand also are involved in the search.
The plane vanished Sunday halfway into what should have been a two-hour hop from Surabaya, Indonesia, to Singapore. Officials saw little reason to believe the flight met anything but a grim fate.
Based on the plane's last known coordinates, the aircraft probably crashed into the water and "is at the bottom of the sea," Soelistyo said Monday.
It is believed to have crashed into Indonesia's Java Sea, a busy shipping lane where water on average is only 45 meters (150 feet) deep, but broad aerial surveys so far have turned up no firm evidence of the missing Airbus A320-200.
On Monday, searchers made various sightings they thought might be related to the plane, but by Tuesday all had been dismissed.
Soelistyo said an Indonesian navy ship reached the spot where a military craft reported two oil patches in the Java Sea east of Belitung island. It was not jet fuel, or even oil, but coral.
"They were just shadows of two wide shapes of coral clusters that when seen from the air looked like oil spills," he said.
The search has expanded to include not only the sea but nearby land. As the sun rose Tuesday over Pangkalan Bun on the western part of Kalimantan, two Indonesian helicopters flew over the island looking for any sign of wreckage. Two other copters were hundreds of kilometers east over the smaller islands of Bangka and Belitung.
"Until now, we have not yet found any signal or indication of the plane's whereabouts," Soelistyo told The Associated Press, adding that fishermen from Belitung island were also helping.
The AirAsia pilots had been worried about the weather on Sunday and had sought permission to climb above threatening clouds, but were denied due to heavy air traffic. Minutes later, the jet was gone from the radar without issuing a distress signal.
Pilots rely on sophisticated weather-radar systems that include a dashboard display of storms and clouds, as well as reports from other crews, to steer around dangerous weather, and it's unlikely that alone would cause the plane to crash.
"A lot more information is available to pilots in the cockpit about weather" than ever, said Deborah Hersman, former chairman of the U.S. National Transportation Safety Board. But the technology has limits and sometimes information about storms "can be a little bit stale."
The suspected crash caps an astonishingly tragic year for air travel in Southeast Asia, and Malaysia in particular. Malaysia-based AirAsia's loss comes on top of the mystery surround Malaysia Airlines Flight 370 in March with 239 people aboard, and the downing of Malaysia Airlines Flight 17 in July over Ukraine, which killed all 298 passengers and crew.
Nearly all the passengers and crew are Indonesians, who are frequent visitors to Singapore, particularly on holidays.
Ruth Natalia Puspitasari, who would have turned 26 on Monday, was among them. Her father, Suyanto, sat with his wife, who was puffy-eyed and coughing, near the family crisis center at Surabaya's airport.
"I don't want to experience the same thing with what happened with Malaysia Airlines," he said as his wife wept. "It could be a long suffering."
Few believe this search will be as perplexing as the ongoing one for Flight 370, which remains a mystery. Authorities suspect the plane was deliberately diverted by someone on board and ultimately lost in a remote area of the Indian Ocean that's thousands of feet deep. Flight 8501 vanished over a heavily traveled sea that is relatively shallow, with no sign of foul play.
The captain, Iryanto, who like many Indonesians uses a single name, had more than 20,000 flying hours, AirAsia said.
People who knew Iryanto recalled that he was an experienced military pilot, flying F-16 fighters before shifting to commercial aviation. His French co-pilot, Remi Plesel, had been in Indonesia three years and loved to fly, his sister, Renee, told France's RTL radio.
"He told me that things were going well, that he'd had a good Christmas. He was happy. The rains were starting," she said. "The weather was bad."
McDowell reported from Jakarta. Associated Press writers Ali Kotarumalos, Niniek Karmini and Margie Mason in Jakarta, Chris Brummitt in Singapore, Joan Lowy in Austin, Texas, Scott Mayerowitz in New York, David Koenig in Dallas and Lori Hinnant in Paris contributed to this report.