An AirAsia jetliner crashed into the Java Sea on Dec. 28, killing all 162 crew and passengers on board the flight from Surabaya, Indonesia, to Singapore. A massive international search is underway for bodies and wreckage. The efforts have been hindered by seasonal monsoon rains that on many days prevent divers and high-tech equipment from making progress. A look at what’s known about the crash and the recovery operation.

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SEARCH FOR BLACK BOXES:

This week, divers and an unmanned underwater vehicle were able to capture the first images of the wreck. The tail of the Airbus A320, partially buried in the seabed, provided a boost to searchers. Officials hope that the cockpit voice and flight data recorders are still in the aircraft’s rear, and experts plan to use a crane or a lifting balloon to hoist the wreckage from the seabed. On Friday, an official said ping-like sounds were heard about a kilometre (half mile) from the tail, but it was unclear if the signals were coming from the black boxes.

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CRASH INVESTIGATION:

It remains unclear what caused Flight 8501 to go down. The last contact the pilots had with air traffic control indicated they were entering stormy weather. They asked to climb from 32,000 feet (9,753 metres) to 38,000 feet (11,582 metres) to avoid threatening clouds, but were denied permission because of heavy air traffic above them. Four minutes later, the plane dropped off the radar. Floating bodies and pieces of debris were found about 10 kilometres (6 miles) from the last point of contact.

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STATUS OF THOSE MISSING:

So far, 48 of the 162 passengers and crew have been recovered, with four new bodies discovered Friday. A few have been found floating while strapped to their seats, but officials say many of those still missing are likely entombed in the fuselage. The bodies are sent to Surabaya for identification and handed over to their families for burial, but the process is becoming more difficult due to decomposition.

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CRASH LOCATION:

The plane went down in the Java Sea about 160 kilometres (100 miles) from Pangkalan Bun on Borneo island, the closest town. The area is being lashed by seasonal rains, causing big waves and murky runoff from rivers that have hampered divers, helicopters and equipment being used to search for the plane. Ships with sonar detectors have identified several large chunks of what is believed to be the plane’s body on the ocean floor.