PERTH, Australia (AP) — A robotic submarine has finished its sixth trip to the bottom of the Indian Ocean in the hunt for wreckage from the missing Malaysia Airlines plane, six weeks after the aircraft mysteriously disappeared, the search coordination center said Saturday.
The Bluefin 21 sub has covered around 133 square kilometers (51 square miles) since it began diving into the depths earlier this week to scan the seabed with sonar. The latest data are being analyzed, and a seventh mission is already underway, it said. So far, no debris has been spotted.
The search has dragged on for more than a month off the coast of western Australia. Nothing from Flight 370 has been recovered, leaving the families of the 239 people on board bewildered and distraught.
On Friday, around three dozen Chinese relatives in Beijing held a prayer meeting for their missing spouses.
Candles burned on a table in the shape of a heart with the letters MH370 in the middle. A banner behind them read in Chinese: "Husband, wife, come home soon."
"There are different relationships touched by grief, from children, to parents, to siblings, and now we wanted spouses to have a chance to release their feelings," said Jack Song, a representative for the relatives. Many of those gathered sobbed as gentle music played and a microphone was passed around for anyone who wished to speak.
Meanwhile, on Saturday, the search continued in Australia. Up to 11 aircraft and 12 ships scanned the ocean surface for debris from the Boeing 777 that vanished en route from Kuala Lumpur, Malaysia, to Beijing on March 8.
Officials have said an oil slick found near the underwater search area is not related to the plane. The parameters of that area were determined based on signals that were believed to be coming from the jet's black boxes. The sounds were last detected April 8, about the time the batteries on the beacons from the all-important flight data and cockpit recorders would have failed.
Radar and satellite data show the plane flew far off-course for unknown reasons and would have run out of fuel in the remote section of the Indian Ocean where the search has been focused.
The underwater hunt is being complicated by the depth of the largely unexplored silt-covered sea floor. The U.S. Navy's unmanned submarine has gone beyond its recommended limit of 4,500 meters (15,000 feet), according to the U.S. 7th Fleet. That could risk the equipment, but it is being closely monitored.
The search coordination center has said the search for floating debris on the surface will continue at least into next week. On Saturday, the visual surface search was to cover an estimated 50,200 square kilometers (19,382 square miles) of sea. The U.S. alone has flown at least 35 missions, racking up 319 hours of flight time over nearly 450,000 nautical miles of ocean, according to the 7th Fleet.
Some families refuse to believe the aircraft crashed into the sea and have instead denounced the search effort as a cover-up.
"We believe the plane and our relatives are still alive. Bring them home, that's all we ask," said one of the Chinese relatives, who would only give his surname, Zhang. "The only way there could be no evidence, no debris is if the plane landed intact."
He and several other family members marched from the prayer service to a local park and held a brief sit-in on Friday.
For other waiting families, each day with no news brings more tortuous doubts as they try to go on living without knowing why their relatives didn't come home.
"We ask that they find the plane, find our loved ones, live or dead, give us something," Song said. "Until the evidence is presented, we have a right to question."
Associated Press writer Christopher Bodeen in Beijing contributed to this report.
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