The Australian Transport Safety Bureau (ATSB) released its report on the Australian-led search in the southern Indian Ocean for the missing Malaysia Airlines flight MH370.
The report, The Operational Search for MH370, records the search for MH370 and Australia’s work on the underwater search, including the ways in which the search area was identified and how the search was conducted.
On March 8, 2014, a Boeing 777 aircraft operating as Malaysia Airlines flight 370 (MH370) was lost during service from Kuala Lumpur, Malaysia to Beijing in the People’s Republic of China, carrying 12 crew and 227 passengers.
Despite the efforts of hundreds of people involved in the search, the aircraft has not been located.
"It is almost inconceivable and certainly societally unacceptable in the modern aviation era with 10 million passengers boarding commercial aircraft every day, for a large commercial aircraft to be missing and for the world not to know with certainty what became of the aircraft and those on board," the report says.
The search for the missing aircraft continued for 1,046 days until Jan. 17, 2017, when it was suspended in accordance with a decision made by Malaysia, Australia and the People’s Republic of China.
The report says that the initial surface search and subsequent underwater search for the aircraft have been the largest searches of their type in aviation history. The 52 days of the surface search involving aircraft and surface vessels covered an area of several million square kilometers. A subsurface search for the aircraft’s underwater locator beacons was also conducted during the surface search.
The report says that the underwater search started with a bathymetry survey that mapped a total of 710,000 square kilometers of Indian Ocean seafloor, the largest ever single hydrographic survey. The high resolution sonar search covered an area in excess of 120,000 square kilometers, also the largest ever search or survey of its kind.
No transmissions were received from the aircraft after the first 38 minutes of the flight. Systems designed to automatically transmit the aircraft’s position, including the transponder and the aircraft communications addressing and reporting system, failed to report the aircraft’s position after this time period.
Later analysis of radar and satellite communication data revealed the aircraft had continued to fly for a further seven hours. Its last positively-fixed position was at the northern tip of Sumatra by surveillance systems operating that night, six hours before it ended the flight in the southern Indian Ocean.
The challenge that faced those tasked with the search was to trace the whereabouts of the aircraft using only the limited data that was available, the report says. This data consisted of aircraft performance information and satellite communication metadata initially, and then later during the underwater search, long-term drift studies to trace the origin of MH370 debris that had been adrift for more than a year, and in some cases, more than two years. The types of data, and the scientific methods used for its analysis, were never intended to be used to track an aircraft or pinpoint its final location.
In April 2014, the surface search for MH370 coordinated by the Australian Maritime Safety Authority (AMSA) was concluded and the Australian Transport Safety Bureau (ATSB) assumed responsibility for conducting the underwater search for the aircraft.
The underwater search area was initially defined at 60,000 square kilometers, and was increased in April 2015 when Malaysia, Australia and the People’s Republic of China agreed to expand the search area to 120,000 square kilometers. The primary objective of the underwater search was to establish whether or not the debris field of the missing aircraft was in the area of seafloor that was defined by expert analysis of the aircraft’s flight path and other information.
In 2015 and 2016 debris from MH370 was found on the shores of Indian Ocean islands and the east African coastline. The debris yielded significant new insights into how and where the aircraft ended its flight. It was established from the debris that the aircraft was not configured for a ditching at the end-of-flight. By studying the drift of the debris and combining these results with the analysis of the satellite communication data and the results of the surface and underwater searches, a specific area of the Indian Ocean was identified that was more likely to be where the aircraft had crashed and sunk.
Understanding of where MH370 may be located is better now than it has ever been, the report says. The underwater search has eliminated most of the high probability areas yielded by reconstructing the aircraft’s flight path and the debris drift studies conducted in recent months have identified the most likely area with increasing precision.
Re-analysis of satellite imagery taken on March 23, 2014, in an area close to the 7th arc has identified a range of objects that may be MH370 debris. This analysis complements the findings of the First Principles Review and identifies an area of less than 25,000 square kilometers that has the "highest likelihood" of containing MH370.
At the time the underwater search was suspended in January 2017, more than 120,000 square kilometers of seafloor had been searched and eliminated with a "high degree of confidence," the report says. In all, 661 "areas of interest" were identified in the sonar imagery of the seafloor. Of these areas, 82 with the most promise were investigated and eliminated as being related to MH370. Four shipwrecks were identified in the area searched.
The reasons for the loss of MH370 cannot be established with certainty until the aircraft is found, the report says.