LOS ANGELES — A 16-year-old Southern California girl attempting a solo sail around the world was feared in trouble Thursday thousands of miles from land in the frigid, heaving southern Indian Ocean after her emergency beacons began signaling and satellite phone communication was lost.

An international effort to rescue young Abby Sunderland began, but the vast distances meant long hours of waiting for her family and support team, which expressed confidence that she was alive because the beacons were deliberately turned on rather than set off automatically.

"She's got all the skills she needs to take care of what she has to take care of, she has all the equipment as well," said brother Zac, himself a veteran of a solo sail around the world at age 17.

Australian Maritime Safety Authority spokeswoman Carly Lusk said three vessels were sent from the French territory of Reunion Island and an aircraft was dispatched from Perth on a four-hour flight to Abby's location more than 2,000 miles from both Africa and Australia.

Qantas airlines said in a statement that an Airbus A330 tasked by the safety authority took off at 7:53 a.m. Friday Perth time and its crew would try to spot the sailboat.

It was not clear when the surface vessels left, but it will take a day for the nearest ship to reach the area. Reunion Island is off Madagascar, the large island along the east coast of Africa.

Support team member Jeff Casher said the two emergency beacons were continuing to broadcast and GPS location data showed they were together and drifting at 1 mph. He believed the beacons were on Abby's boat but said they could be with her on a raft.

Casher offered several scenarios: The boat might have flipped over and Abby could still be inside; the boat's mast might have been damaged; or she was injured and could not pilot the boat. He said that if the boat flipped, the hull would prevent her from calling from her satellite phone.

Conditions can quickly become perilous for any sailor exposed to the elements in that part of the world.

"We've got to get a plane out there quick," said family spokesman Christian Pinkston, adding that the teen's family in Thousand Oaks was asking for prayers for her safety.

Her brother said Abby was prepared and mentally tough. "I really wish I could see her and hope she gets through this one," he told reporters outside the family home.

Abby last communicated with her family at 4 a.m. PDT Thursday and reported 30-foot swells but was not in distress, Pinkston said.

Casher said Abby had to make repeated calls with her Iridium satellite phone because of sketchy connections. He said she had been in rough weather and had a problem with her engine, which she eventually managed to start. The team then asked her to check other things on the boat.

"She hung up to go check some things and she never did call back," he said.

An hour later, the family was notified that her emergency beacons had been activated, and there was no further communication.

Her brother said the boat was most likely not completely submerged because another beacon would be triggered at a depth of 15 feet.

Derrick Fries, a U.S. sailing instruction and safety expert, said Abby's circumstances were very unclear.

"It's hard to determine if she's rolled over, swamped, or washed overboard. She has to have a dry suit on to have any chance," he said. "To be capsized in the middle of the ocean with waves crashing relentlessly down, not just for hours, but days, I can't tell you how difficult those conditions are."

A lifelong sailor whose father is a shipwright and has a yacht management company, Abby set sail from Los Angeles County's Marina del Rey in her 40-foot boat, Wild Eyes, on Jan. 23 in an attempt to become the youngest person to sail around the world alone without stopping. Her brother briefly held the record in 2009.

Before Abby's voyage began, her brother described her as having more skill and experience than most sailors in their 20s and 30s. Her father said she had more solo sailing experience than Zac did before he started out.

"He totally thinks that I'm ready to do it, so that does help," she said at the time.

Abby soon ran into equipment problems and had to stop for repairs. She gave up the goal of setting the record in April, but continued on.

On May 15, Australian 16-year-old Jessica Watson claimed the record after completing a 23,000-mile circumnavigation in 210 days. Jessica and her family sent a private message of hope to Abby's family, spokesman Andrew Fraser said. "We are hoping she's OK and are trying to stay positive," he said.

Abby left Cape Town, South Africa, on May 21 and on Monday reached the halfway point of her voyage.

On Wednesday, she wrote in her log that it had been a rough few days with huge seas that had her boat "rolling around like crazy."

"I've been in some rough weather for awhile with winds steady at 40-45 knots with higher gusts," she wrote. "With that front passing, the conditions were lighter today. It was a nice day today with some lighter winds which gave me a chance to patch everything up. Wild Eyes was great through everything but after a day with over 50 knots at times, I had quite a bit of work to do."

Information on her website said that as of June 8 she had completed a 2,100-mile leg from South Africa to north of the Kerguelen Islands, taking a route to avoid an ice hazard area. Ahead of her lay more than 2,100 miles of ocean on a 10- to 16-day leg to a point south of Cape Leeuwin on the southwest tip of Australia.

Charlie Nobles, executive director of the American Sailing Association, said the best-case scenario would be that she had had a severe knockdown or roll by a strong wave that caused her communication equipment to go out, or the boat sustained structural damage that was preventing her from sailing.

The worst case would be if she was in the water or in her life raft.

"It's an extreme set of conditions with the winds, the force of the waves," he said.

A person lost at sea can typically survive 12 days on average without fresh water and a month without food, according to survival experts.

If the boat capsized, survival will depend on factors including water temperature, sea conditions, safety gear and whether there was something to hold on to.

Last year a Netherlands court concerned about safety blocked a 13-year-old girl's plan to sail around the world, sparking debate on the role of authorities and parents when children want to undertake risky adventures.

Such attempts have resulted in success and tragedy.

Last month, 13-year-old Jordan Romero of Big Bear, Calif., became the youngest person to scale 29,035-foot Mount Everest. But in 1996, 7-year-old Jessica Dubroff, her father and a flight instructor were killed in a crash in Cheyenne, Wyo., during her attempt to become the youngest person to fly across the country.

Online: www.soloround.blogspot.com

Associated Press writers Jacob Adelman and Nardine Saad in Thousand Oaks and Alicia Chang, Christina Hoag, Shaya Tayefe Mohajer and Sue Manning in Los Angeles contributed to this report.