The missing Malaysia Airlines plane is not in the Indian Ocean search zone where acoustic “pings” were detected, search co-ordinators have confirmed.

“The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgment, the area can now be discounted as the final resting place of MH370,” the Joint Agency Co-ordination Centre said on Thursday.

JACC announced on April 7 that a pinger locator towed from the Australian navy vessel Ocean Shield had picked up two acoustic signals, with one held for more than two hours.

At the time, it described the signals as consistent with flight data or cockpit voice recorders, the most promising lead yet and likely from a man-made source.

Two days later, two more signals were detected, holding for about five and seven minutes.

Earlier today the Navy’s deputy director of ocean engineering Michael Dean told CNN there was now broad agreement that the four acoustic transmissions came from some other man-made source unrelated to the jet that disappeared on March 8 carrying 239 people.

He said if the ping-emitting beacons had come from the plane’s onboard data or voice recorders they would have been found by now.

“Our best theory at this point is that (the pings were) likely some sound produced by the ship … or within the electronics of the towed pinger locator,” Dean said.

“Always your fear any time you put electronic equipment in the water is that if any water gets in and grounds or shorts something out, that you could start producing sound,” Dean added.

JACC has also confirmed the end of the Bluefin-21 mission, with the underwater drone detecting no signs of aircraft debris since it began scanning the sea floor off the West Australian coast on April 14.