A week after Indonesia AirAsia QZ8501 crashed into the Java Sea presumably killing all 162 people on board, search teams are expected to intensify the hunt for the still missing aircraft and its black boxes.
Typically painted orange for easy detection, the black boxes, as they are referred to, record conversations in the cockpit and preserve data on aircraft position and speed - which can be crucial in determining the cause of accidents.
With dozens of bodies and some pieces of wreckage already recovered from the Airbus 320-200, which crashed enroute from Surabaya to Singapore, air crash experts expect the main body of the plane and the aircraft recorders to be found within the week or so.
When SilkAir MI185 crashed into the Musi River near Palembang, Indonesia, in December 1997, it took nine days to find the black boxes. A decade later, when a plane belonging to the now- defunct Indonesian carrier Adam Air crashed at sea off Sulawesi Island, the recorders were recovered after three weeks.
An Indonesia-led, multi-nation search based in Pangkalan Bun, a town in southern Borneo closest to the QZ8501 search area, is currently concentrating on about 1,350 square nautical miles of the northern Java Sea.
It would have been still dark when Captain Iriyanto and his French co-pilot Remi Emmanual Plesel, along with the flight's four cabin crew and one engineer, arrived at Surabaya's Juanda Airport.
Weather charts issued before the flight showed that the plane's scheduled route at cruising level would come across "worrying" conditions, Indonesia's weather officials said in a report last Friday.
Satellite images also suggested temperatures of minus 80 deg C to minus 85 deg C, which meant there were grains of ice in the dense clouds.
It is unclear if the information was conveyed to the pilots.
At 5.30am, QZ8501 took off with 23 no-shows, including a family of 10 which missed the flight because they did not get the message from the airline informing them of a change in flight time. They had likely booked their tickets before the end of March, after which the airline brought forward the flight timing from 7.20am to 5.20am local time.
In a bizarre development, Indonesia's Transport Ministry is now saying the airline did not in fact have approval to operate the sector on Sundays, and has suspended services pending checks.
A key question is why air traffic control was unaware of this.
For the 155 passengers on board the flight that Sunday morning - all were Indonesians except for a two-year-old Singaporean girl, a Malaysian, one Briton and three South Koreans - the day had presumably started out uneventfully.
The first hint of trouble came about 45 minutes into the flight, at 6.12am local time, when the cockpit contacted air traffic control for permission to turn left to avoid a storm.
The pilots also asked for approval to climb from 32,000 feet to 38,000 feet, which was denied because there were other aircraft flying higher.
Clearance was given for QZ8501 to climb to 34,000 feet, but when this was conveyed to the cockpit, there was no response.
At 7.55am local time - an hour behind Singapore time - AirAsia declared the plane missing.
And at Changi Airport Terminal 1, where the plane had been scheduled to land at 8.30am, relatives and friends of those on board waited.