The Seventh Arc
Information and analysis of satellite data and drift modelling identified an area set out in the map and labelled as the 7th arc. At the time MH370 reached this arc, the aircraft is considered to have exhausted its fuel and to have been descending. As a result, the aircraft is unlikely to be more than 27.5 NM (51 km) to the west or 25 NM (46 km) to the east of the arc.
Based on all the independent analysis of satellite communications and aircraft performance, the total extent of the 7th arc reaches from latitude 20 degrees S to 40 degrees S.
Before the underwater search for MH370 could begin, it was necessary to accurately map the seafloor to ensure that the search is undertaken safely and effectively. Bathymetric survey vessels spent months at sea, scanning the seafloor with multibeam sonar to gather detailed, high-resolution data. The data has revealed many seabed features for the first time.
In addition to locating the aircraft, the underwater search aimed to map the MH370 debris field in order to identify and prioritise the recovery of specific aircraft components, including flight recorders, which will assist with the Malaysian investigation. The ATSB utilised the data from the bathymetric survey work to prepare the initial plan for the underwater search, to be followed and referred to by all parties involved. The plan includes search timings, methods, procedures, safety precautions and the initial search areas for the various vessels.
Additional maps showing previous search area, the progress of the bathymetric survey and detail of the undersea terrain are available in the gallery at our Images web page.