SINGAPORE, Jan 16  — The first time the experts from Singapore tried to sail out, they had to turn back because the waters in the Java Sea suddenly became very choppy.

And because their port was far away from where pings from the black boxes of the doomed AirAsia jet were first detected, it took them 18 hours to reach the 144 sq km area where the flight recorders were believed to be, rendering many of them seasick.

“We knew the flight recorders had limited lifespans ... so we wanted to be as close to the search zone as soon as we could. But the choppy seas gave us a really tough job the first time round,” recounted Jamie Chen, deputy chief hydrographer at the Maritime and Port Authority (MPA).

He, along with 11 colleagues, returned home yesterday after a 12-day stint assisting French and Indonesian investigators in pinpointing the flight recorders.

The flight recorders, popularly known as black boxes, were recovered on Monday and Tuesday, more than two weeks after the AirAsia plane, with 162 people onboard, crashed into the Java Sea on Dec 28.

Chen was part of a 12-man Singapore team — comprising five other MPA specialists, four experts from the Transport Ministry’s Air Accident Investigation Bureau (AAIB) and two officers from the Civil Aviation Authority of Singapore — who set off for the search zone on New Year’s Eve.

The team operated from Indonesian vessels KN Jadayat and KN Andromeda.

The second deployment was more successful and the AAIB specialists managed to hear the pings underwater using a hydrophone, which allowed them to significantly narrow down the search area to 9 sq km, Chen said.

The MPA officers then deployed their side scan sonar and remotely-operated vehicle to verify and take pictures of the wreckage underwater, which were shared with the Indonesian naval divers.

Chen, 48, added that the naval divers aided the smooth recovery of the black boxes despite battling four-metre high waves and strong currents.

“They had limited time underwater due to bad weather conditions … they progressively searched day after day and that’s how they found the boxes,” he said.

Welcoming the team home at Changi Airport, Transport Minister Lui Tuck Yew said it was an “emotionally and physically demanding” mission and acknowledged that their Indonesian counterparts also did a sterling job.

“I also know if it was difficult for (the rescue team), how much more it would be for the family members still awaiting news of the incident and recovery of bodies.

“I send my condolences first to the next-of-kin and hope that now that the fuselage is found, we will be able to accelerate the phase of recovering and identifying the bodies,” Lui said. — TODAY