(Bloomberg) -- Searchers trying to locate the cockpit voice recorder of the Lion Air jet that crashed into the Java Sea off Indonesia face a new challenge as an electronic signal from the device fades.

“The ping sound is getting hard to detect and is disappearing,” according to Haryo Satmiko, deputy chief of Indonesia’s National Transportation Safety Committee. A new underwater locator with better sensitivity to detect the ping from the so-called black box is ready for deployment to help the search.

If that fails, the safety committee will deploy a ship with mud-suction ability to try to recover the voice recorder.

“We suspect the cockpit voice recorder is covered by mud because the flight data recorder, when it was found, was about a half meter deep buried in the mud,” Satmiko said by text message Saturday.

The recovery of the voice recorder would help investigators piece together the final moments before flight JT610 dove into the sea with 189 people on board on Oct. 29. Preliminary findings based on information from the data recorder, which has been recovered, indicated a technical snag related to faulty airspeed reading.

That prompted Boeing Co., the maker of the plane, to alert operators of the 737 Max aircraft worldwide that the airflow sensor can provide false readings in certain circumstances.

Indonesia’s domestic airline market has boomed in recent years to become the fifth-largest in the world. Local air traffic more than tripled between 2005 and 2017 to 97 million people, according to the CAPA Center for Aviation, and is dominated by flag carrier PT Garuda Indonesia and Lion Air Group.

Local carriers have struggled with safety issues, partly as a result of the pace of that expansion, as well as issues intrinsic to a region of mountainous terrain, equatorial thunderstorms and often underdeveloped aviation infrastructure.

To contact the reporter on this story: Rieka Rahadiana in Jakarta at rrahadiana@bloomberg.net

To contact the editors responsible for this story: Niluksi Koswanage at nkoswanage@bloomberg.net, John McCluskey, Subramaniam Sharma

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