VIDEO: MH370 Towfish Trials

The search for missing Malaysian Airline has now covered over 22,000 square kilometres of the seafloor, which is around 36 per cent of the priority search area.

Assuming no other significant delays with vessels, equipment or from the weather, the current underwater search area may be largely completed around May 2015.

According to ATSB, following bad weather associated with two tropical cyclones in the area, conditions prevented the safe launch/retrieval of search equipment between 1 and 5 February. The vessels evaded the storms and resumed search operations in the following days.

Latest ship movement reports by ATSB say that GO Phoenix arrived in the search area and recommenced search operations on February 10.

Fugro Equator suspended underwater search operations on February 11 in order to travel to Fremantle for a scheduled port visit. The vessel is anticipated to arrive in port around February 17.

Fugro Discovery suspended underwater search operations around February 12 in order to travel to Fremantle for a scheduled port visit. The vessel is anticipated to arrive in port around February 18.

Fugro Supporter is scheduled to suspend underwater search operations around February 14 in order to travel to Fremantle for a scheduled port visit. The vessel is anticipated to arrive in port around February 20.

Equipment used in the underwater search

The underwater search is being carried out using two different types of subsea vehicles.

GO Phoenix, Fugro Discovery and Fugro Equator are equipped with towed vehicles (towfish) equipped with synthetic aperture sonar, side scan sonar and multi-beam echo sounders. The vehicles are towed behind the vessel on very long cables (up to 10 kilometres) at an altitude between 100 and 150 metres above the sea floor. The length of tow cable deployed is used to control the altitude of the towfish. The sonar instruments on the towfish collect data which is relayed in real time to the vessels where it is processed and analysed to determine if there is any evidence of debris on the seafloor associated with MH370.

Footage of ‘Dragon Prince’, the EdgeTech DT-1 towfish that is being used on Fugro Discovery to search the seafloor for MH370. In this film, Dragon Prince is launched for the first time by Fugro crewmembers as they test its capabilities.

Fugro Supporter is equipped with a Kongsberg HUGIN 4500 autonomous underwater vehicle (AUV). AUVs are self-propelled underwater vehicles which are very manoeuvrable. They can turn, ascend and descend rapidly to maintain a constant altitude above the seafloor in areas of challenging bottom topography. For this reason the HUGIN 4500 on Fugro Supporter is being used to search areas which are difficult or inefficient for the towed systems to search.

The HUGIN 4500 AUV is equipped with instruments identical to the towfish on Fugro Discovery and Fugro Equator. The AUV is launched from the vessel, dives to the correct altitude above the seafloor and then spends up to 24 hours gathering sonar data in a pre-programmed search pattern. When the mission is complete, the AUV surfaces and is recovered by the vessel, where the data is downloaded and the batteries changed, ready for the next mission.

Source: ATSB, video/photo by ABIS Chris Beerens, RAN