China’s deep-sea manned submersible Jiaolong was forced to surface ahead of schedule after suffering from engine failure in the southwestern Indian Ocean, Xinhua News Agency reported Sunday.
Jiaolong, whose name means "flood dragon" in Chinese, was collecting scientific specimens as part of a four-month expedition in the Indian Ocean when it raised an "insulation alert" as it reached the sea floor.
"When we started to collect rocks and sulfide, we heard big noise [sic] from the sub. I thought the sub might collide with some seabed rocks, but the noise was still there when I took the sub away," Fu Wentao, the sub's pilot, said in an interview with Xinhua.
Engineers from the support ship Xiangyanghong 09 assumed that the noise was due to an engine malfunction, and the chief commander of the mission, Yu Hongjun, decided to have the sub return to the surface in line with safety regulations.
The problem was later confirmed as head engine failure, and the sub was returned to the support ship at 12:35 p.m. (GMT+4:00), five hours ahead of schedule.
"It's lucky that the sub stopped the mission in time and came up as soon as possible, or it might be in danger," one of the engineers said.
Repairs of the engine are underway as of Saturday night.
Capable of diving over 7,000 meters, Jiaolong has the greatest depth range of any manned research vehicle in the world. In 2012, it reached its deepest dive of 7,062 meters in the Mariana Trench in the western Pacific Ocean.