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The Operational Search for MH370

Executive summary

On 8 March 2014, a Boeing 777 aircraft operated as Malaysia Airlines flight 370 (MH370) was lost during a flight from Kuala Lumpur in Malaysia to Beijing in the People’s Republic of China carrying 12 crew and 227 passengers. The search for the missing aircraft commenced on 8 March 2014 and continued for 1,046 days until 17 January 2017 when it was suspended in accordance with a decision made by a tripartite of Governments, being Malaysia, Australia and the People’s Republic of China.

The initial surface search and the subsequent underwater search for the missing 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 kilometres. A sub surface search for the aircraft’s underwater locator beacons was also conducted during the surface search.

The underwater search started with a bathymetry survey which continued as required throughout the underwater search and has mapped a total of 710,000 square kilometres of Indian Ocean seafloor, the largest ever single hydrographic survey. The high resolution sonar search covered an area in excess of 120,000 square kilometres, also the largest ever search or survey of its kind. Despite the extraordinary efforts of hundreds of people involved in the search from around the world, the aircraft has not been located.

Regardless of the cause of the loss of MH370, there were no transmissions 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 transmit the aircraft’s position after this time period. Subsequent analysis of radar and satellite communication data revealed the aircraft had actually continued to fly for a further seven hours. Its last position was positively fixed at the northern tip of Sumatra by the surveillance systems operating that night, six hours before it ended the flight in the southern Indian Ocean.

The challenge which faced those tasked with the search was to trace the whereabouts of the aircraft using only the very limited data that was available. 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 which 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 pin point its final location.

On 28 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 kilometres, and was increased in April 2015 when the Tripartite Governments (Malaysia, Australia and the People’s Republic of China) agreed to expand the search area to 120,000 square kilometres. 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 defined by expert analysis of the aircraft’s flight path and other information. If a debris field was located, the search needed to confirm the debris was MH370 by optical imaging, and then map the debris field to enable planning for a subsequent recovery operation.

Once underwater search operations commenced in October 2014, the MH370 debris field could potentially have been located at any time. A recovery operation would need to have commenced as soon as possible after the debris field was located and the Tripartite governments had agreed on the next steps. The ATSB's role was therefore to also put in place the arrangements and plans necessary for a rapid recovery operation to occur at short notice.

The underwater search applied scientific principles to defining the most probable area to be searched through modelling the aircraft’s flight path and behaviour at the end of the flight. The flight path modelling was based on unique and sophisticated analysis of the metadata associated with the periodic automated satellite communications to and from the aircraft in the final six hours of the flight. The end-of-flight behaviour of the aircraft, when MH370 was considered to have exhausted its fuel, has been analysed and simulated.

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 which was more likely to be where the aircraft ended the flight.

The understanding of where MH370 may be located is better now than it has ever been. 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 the past 12 months have identified the most likely area with increasing precision. Re-analysis of satellite imagery taken on 23 March 2014 in an area close to the 7th arc has identified a range of objects which may be MH370 debris. This analysis complements the findings of the First Principles Review and identifies an area of less than 25,000 square kilometres which has the highest likelihood of containing MH370.

The ATSB’s role coordinating the underwater search involved the procurement and management of a range of sophisticated and highly technical services. Management of the underwater search was aimed at ensuring high confidence in the acquisition and analysis of the sonar search data so that areas of the seafloor which had been searched could be eliminated. A comprehensive program was implemented to ensure the quality of the sonar coverage. A thorough sonar data review process was used to ensure areas of potential interest were identified and investigated.

During the early stages of the procurement, careful consideration was given to the methods available for conducting a large scale search of the seafloor. Water depths were known to be up to 6,000 m with unknown currents and unknown seafloor topography. Search operations would also have to be conducted in poor weather conditions and in a very remote area far from any land mass. Planning focused on selecting a safe, efficient and effective method to search the seafloor in an operation with an indeterminate timeframe.

The mapping of the seafloor in the search area revealed a challenging terrain for the underwater search which used underwater vehicles operating close to the seafloor. While the deep tow vehicles selected as the primary search method proved to be very effective, the seafloor terrain necessitated the use of a range of search methods including an autonomous underwater vehicle to complete the sonar coverage.    

The underwater search area was located up to 2,800 km west of the coast of Western Australia and the prevailing weather conditions in this area for much of the year are challenging. Crews on the search vessels were working for months at a time in conditions which elevated the operational risks. The ATSB ensured that these risks to the safety of the search vessels and their crews were carefully managed.

At the time the underwater search was suspended in January 2017, more than 120,000 square kilometres of seafloor had been searched and eliminated with a high degree of confidence. 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 intention of this report is to document the search for MH370, in particular, the underwater search including; where the search was conducted (and why), how the search was conducted, the results of the search and the current analysis which defines an area where any future underwater search should be conducted. The report also includes a safety analysis which is focused on the search rather than on discussing the range of factors which may have led to the loss of the aircraft.

The Government of Malaysia is continuing work on their investigation of the facts and circumstances surrounding the loss of MH370 aircraft consistent with their obligations as a member State of ICAO. The Malaysian investigation is being conducted in accordance with the provisions of ICAO Annex 13, Aircraft Accident and Incident Investigation.  

The search, recovery and investigation of the loss of Air France flight AF447, in the South Atlantic Ocean in 2009, and the loss of MH370 have led to some important learnings related to locating missing aircraft on flights over deep ocean areas. Requirements and systems for tracking aircraft have been enhanced and will continue to be enhanced. Steps are being taken to advance other aircraft systems including emergency locator transponders and flight recorder locator beacons.

The ATSB acknowledges the extraordinary efforts of the hundreds of dedicated professionals from many organisations in Australia and around the world who have contributed their time and efforts unsparingly in the search for MH370.  

The reasons for the loss of MH370 cannot be established with certainty until the aircraft is found. 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 ATSB expresses our deepest sympathies to the families of the passengers and crew on board MH370. We share your profound and prolonged grief, and deeply regret that we have not been able to locate the aircraft, nor those 239 souls on board that remain missing.

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Download CSIRO Drift report Part IV
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The search for MH370 and ocean surface drift – Part IV

Executive summary

This short report re-examines the question of how effective the March-April surface search was for ‘ruling out’ segments of the 7th arc as being the location of MH370.

One might think that even if the debris field was within a particular day’s search box that the probability of detecting the debris could be small because the spacing between the search tracks was necessarily large (in order to cover the vast distances searched) compared to the detection range. This would certainly be correct if either 1) the number of debris items was small, or 2) the debris items were all close to each other.

We now know (from the number of items that have been found washed ashore) that the number of floating debris items was not small. But while we cannot prove that these were not all close to each other and therefore potentially overlooked, the chance of this happening is very low. Winds, waves and ocean turbulence disperse objects, potentially over large distances after a week at sea. The rate of spreading of the debris field increases as time passes, as stretching and shearing by ever-larger ocean eddies takes place.

In this report we show that the debris field resulting from an example crash site at 30.5°S on the 7th arc was 1) largely within the bounds of the area searched during 5 days, and 2) probably spread out across a distance spanning several of the search tracks. Consequently, there were many opportunities for debris to be detected, suggesting that the probability of all debris items being overlooked is small.

Our re-assessment of the surface search benefits from 1) the evidence that an extensive debris field was indeed there to be found, and 2) refined estimates of the surface currents, allowing us to re-assess how well the search boxes overlapped with the potential locations of the debris fields.


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Download CSIRO Drift Report III
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The search for MH370 and ocean surface drift – Part III

Executive summary

Several high-resolution surveillance satellites were tasked to obtain images of the ocean in the vicinity of the 7th arc while the surface search for missing flight MH370 was underway in March 2014. Many objects of interest were seen in several of these images from a wide range of locations at the time, but none led to any successful recoveries. Four of these images, taken just west of the 7th arc in the vicinity of the new search area proposed by ATSB in 2016, have recently been carefully re-examined (Minchin et al. 2017). Three of these images (referred to as PHR4, PHR3 and PHR1) contained 9, 2 and 1 objects, respectively, that were classified as “probably man-made” as well as 28 “possibly man-made” objects. The dimensions of these objects are comparable with some of the debris items that have washed up on African beaches and their location near the 7th arc makes them impossible to ignore. But there is no evidence to confirm that any of these objects (let alone all) are pieces of 9M-MRO (the aircraft flying as MH370).

To completely reject the possibility that any of these objects are pieces of 9M-MRO is difficult to defend. Consequently, we have addressed the obvious question raised by this new piece of uncertain, but plausibly-relevant evidence:

If at least some objects in the images are pieces of 9M-MRO, from where did they drift in the weeks between the disappearance of the aircraft and image capture?

This question is, perhaps surprisingly, potentially more difficult to answer than the ones we addressed in the two reports preceding this one. This is because it requires a very detailed knowledge of the surface currents out in the middle of the ocean where almost no in-situ observations have ever been made. However, thanks to the combined data sets from several types of Earth-observation satellites, coupled with the computational power of Australia’s most powerful super-computer and more than a decade of Government investment in operational ocean modelling, we think we have succeeded.

Taking drift model uncertainty into account, we have found that the objects identified in most of the images can be associated with a single location within the previously-identified region suggested by other lines of evidence. Furthermore, we think it is possible to identify a most-likely location of the aircraft, with unprecedented precision and certainty. This location is 35.6°S, 92.8°E. Other nearby (within about 50km essentially parallel to the 7th arc) locations east of the 7th arc are also certainly possible, as are (with lower likelihood) a range of locations on the western side of the 7th arc, near 34.7°S 92.6°E and 35.3°S 91.8°E. While we cannot be totally sure which of these locations in the southern half of the 2016-proposed search area is most likely, we do have a high degree of confidence that an impact in the southern half of the 2016-proposed search area, near 35°S, is more consistent with detection of debris in the images than is an impact in the northern half.


Download CSIRO Drift Report III
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Download Geoscience Australia satellite imagery analyses report
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Summary of imagery analyses for non-natural objects in support of the search for Flight MH370

Results from the analysis of imagery from the PLEIADES 1A satellite undertaken by Geoscience Australia

Geoscience Australia (GA) was asked to assist the Australian Transport Safety Authority (ATSB) in the analysis of a set of four Airbus PLEIADES 1A images. GA received these images for analysis on the 23rd March 2017.

The data was acquired over the Indian Ocean on the 23rd March 2014. The analysis performed by GA was to determine whether the images included objects that were potentially man-made in origin. GA analyses included semi-automatic workflows and a number of potential objects were identified.

The overall location of the study area is shown in Figure 1, and a detailed overview of the four scenes with associated detected objects is shown in Figure 2. Figure 3 details the relationship between the PLEIADES data and other MH370 search-related activities.

The appendix to the report presents a data summary for each of the images. This includes a browse image of each scene, including the object locations, a cross plot of the representative spectral radiances observed in the image, a table of the object locations plus size metrics and an indicative label as to the object’s origin. The detected objects are shown in true colour and in a false colour derived from Principle Components Analysis (PCA) to help distinguish objects from their surroundings.


Download Geoscience Australia satellite imagery analyses report
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Download CSIRO Drift report 2
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The search for MH370 and ocean surface drift

Executive summary - Report II

This report explores the possibility that an improved ability to simulate the path taken by the flaperon across the Indian Ocean might yield an improved estimate of the location of the remains of the aircraft on the sea floor.

Our earlier field testing of replicas of the flaperon was unable to confirm numerical predictions by the Direction Generale de L’Armement (DGA) that the flaperon drifted left of the wind. Field testing of a genuine Boeing 777 flaperon cut down to match photographs of 9M-MRO’s flaperon has now largely confirmed the DGA predictions, at least with respect to drift angle. The impact of this information on simulated trajectories across the Indian Ocean is that the July 2015 arrival time at La Reunion is now very easy to explain.

This new information does not change our earlier estimate of the most probable location of the aircraft. It does, however, increase our confidence in that estimate, so we are now even more confident that the aircraft is within the new search area identified and recommended in the MH370 First Principles Review (ATSB 2016).

The proposed new search area has been determined by combining many lines of evidence, the strongest being that the descent began close to the SatCom 7th arc. The following evidence from drift modelling helps indicate where along the 7th arc the aircraft impacted the sea surface:

  • The July 2015 arrival date of the flaperon at La Reunion island is consistent with impact occurring between latitudes 40°S and 30.5°S.
  • Arrival off Africa of other debris exclusively after December 2015 favours impact latitudes south of 32°S, as does the failure of the 40-day aerial search off Western Australia to find any floating debris.
  • Absence of debris findings on Australian shores is only consistent with a few impact latitudes – the region near 35°S is the only one that is also consistent with other factors.

The new search area, near 35°S, comprises thin strips either side of the previously-searched strip close to the 7th arc. If the aircraft is not found there, then the rest of the search area is still likely to contain the plane. The available evidence suggests that all other regions are unlikely.

Download CSIRO Drift report 2
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Download Final Report
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This report documents the proceedings and outcomes of the First Principles Review meeting on the search for missing Malaysia Airlines flight MH370 held in Canberra from 2 to 4 November 2016. Participants consisted of experts in data processing, satellite communications, accident investigation, aircraft performance, flight operations, sonar data, acoustic data and oceanography. The purpose of the meeting was to reassess and validate existing evidence and to identify any new analysis that may assist in identifying the location of the missing aircraft.

Throughout the search, the ATSB has issued several reports updating the definition of the search area based on analysis progressively refined, or when new information has come to light. This document complements those reports and provides a summary of the detailed analysis of the satellite data combined with new evidence derived from the modelling of the drift of debris from the aircraft.

The experts attending the meeting considered:

  • The results of the search to date.
  • Satellite communication metadata and its analysis including methodology, assumptions, limitations, the probability distributions of possible flight paths, and validation results.
  • Results from simulations and the aircraft manufacturer’s analysis of aircraft performance.
  • The width of the search area based on what is known about the end of the flight.
  • Hydro-acoustic analysis potentially relevant to the search.
  • Failure analysis of recovered debris.
  • Drift analysis of aircraft debris.  

For background information, please refer to the previous ATSB publications available online at www.atsb.gov.au/mh370

The updated independent analysis of the satellite data and the drift analysis consistently identified the most likely impact location of MH370 as being close to the 7th arc[1] (within ~25 NM) and bounded by latitudes of approximately 33°S to 36°S.

There is a high degree of confidence that the previously identified underwater area searched to date does not contain the missing aircraft. Given the elimination of this area, the experts identified an area of approximately 25,000 km² as the area with the highest probability of containing the wreckage of the aircraft. The experts concluded that, if this area were to be searched, prospective areas for locating the aircraft wreckage, based on all the analysis to date, would be exhausted.


[1]     The 7th arc is an arc of possible aircraft positions, equidistant from Inmarsat’s Indian Ocean Region satellite, where the accident aircraft made the final series of satellite communications transmissions. It is the key datum in the search for MH370 and its derivation is described in previous ATSB search area definition reports.  

Download Final Report
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The First Principles Review

Satellite data

Width of the search area

Drift analysis

Residual Probability Map


Download CSIRO Drift Report 1
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The search for MH370 and ocean surface drift

Executive summary - Report 1

This report details the results of a comprehensive attempt to use drift modelling to inform efforts to locate the missing Malaysia Airlines flight MH370 (registered 9M-MRO). It differs from earlier attempts to do this in several important ways, which, along with other developments, have enabled it to come up with a location of the aircraft that is much more precise than we thought was possible.

We have concluded that the northern third (from 36°S to 33°S or perhaps 32°S) of the initial search area uniquely remains prospective. This northern area was partially searched (close to the 7th arc) in the latter half of 2014 and early 2015. Locations outside the searched area, but still within a likely distance from the arc, remain unsearched. The region near 35°S is particularly prospective because there is strong evidence (from Earth-observation satellite data) that this is where, at the time of the accident and for weeks after, the debris field would have been carried north-west for about 500km, away from where the March-April 2014 surface search was conducted and away from the shores of Western Australia (WA). The scenario of a final location near 35°S is the one that is most consistent with:

  • the absence of debris findings on the WA coastline
  • the absence of debris findings during the aerial and surface search
  • the July 2015 arrival time of the flaperon at La Reunion
  • the December 2015 and onwards (only) arrival times of debris in the western Indian Ocean.

The uncertainty of this finding has been greatly reduced from what was possible earlier by:

  • measuring the wind-driven drift rate of replica aircraft parts alongside oceanographic drifters (whose travel times across the Indian Ocean are well known), and
  • using a new ocean model that is informed by very accurate satellite measurements of small perturbations of sea level, yielding estimates of surface currents that have been validated using the global archive of oceanographic drifters.

Are other regions also prospective?

If the flaperon had remained the only piece of debris found we would have to say ‘perhaps’, but now many debris items have been found, we can conclude that regions north of 32°S and south of 39°S are both less likely. Drift modelling suggests that debris items originating north of 32°S would probably have been detected by the surface search, and that items would have probably arrived in Africa before December 2015. Regions south of 39°S are not prospective either, because debris from those regions would more likely have turned up on Australian coastlines than west Indian Ocean ones.

Download CSIRO Drift Report 1
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Download search and debris update
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MH370 – Search and debris examination update

Published: 2 November 2016

Amended: 2 December 2016 - Correction to Figure 11 caption text under image to remove inconsistency with report text on Page 17.

Executive summary

This report provides an update to the MH370 search area definition described in previous ATSB reports. It comprises further analysis of satellite data, additional end of flight simulations, a summary of the analysis of the right outboard wing flap, and preliminary results from the enhanced debris drift modelling.

For background information, please refer to the ATSB publications available online at www.atsb.gov.au/mh370:

  • Definition of underwater search areas, 18 August 2014
  • Flight Path Analysis Update, 8 October 2014
  • Definition of Underwater Search Area Update, 3 December 2015.

The Australian Defence Science and Technology (DST) Group[1] conducted a comprehensive analysis of the Inmarsat satellite communications (SATCOM) data and a model of aircraft dynamics. The output of the DST Group analysis was a probability density function (PDF) defining the probable location of the aircraft’s crossing of the 7th arc.

Details of this analysis and the validation experiments are available in the open source published book here: http://link.springer.com/book/.

Additional analysis of the burst frequency offsets associated with the final satellite communications to and from the aircraft is consistent with the aircraft being in a high and increasing rate of descent at that time. Additionally, the wing flap debris analysis reduced the likelihood of end-of-flight scenarios involving flap deployment.

Preliminary results of the CSIRO’s drift analysis indicated it was unlikely that debris originated from south of the current search area. The northernmost simulated regions were also found to be less likely. Drift analysis work is ongoing and is expected to refine these results.


  1. Formerly the Defence Science and Technology Organisation (DSTO)
Download search and debris update
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7th arc burst frequency offset (BFO) analysis

End of flight simulations

Drift modelling update

Debris summary and analysis



These debris examination reports are released with the concurrence of the Malaysian ICAO Annex 13 Safety Investigation Team for MH370.

Debris Report 1 (19 April 2016)

Debris Report 2 (12 May 2016)

Debris Report 3 (15 September 2016)

Debris Report 4 (22 September 2016)

Debris Report 5 (7 October 2016)


At 1722 Coordinated Universal Time on 7 March 2014, Boeing 777-200ER aircraft, registered 9M-MRO and operating as Malaysia Airlines Flight MH370, disappeared from air traffic control radar and a search was commenced by Malaysian authorities. The aircraft had taken off from Kuala Lumpur, Malaysia on a scheduled passenger service to Beijing, China with 227 passengers and 12 crew on board.

Under Annex 13 to the Convention on International Civil Aviation Aircraft Accident and Incident Investigation (Annex 13) Malaysia, as the country of registration, has investigative responsibility for the accident.

On 31 March 2014, the Malaysian Government accepted the Government of Australia’s offer to take the lead in the search and recovery operation in the southern Indian Ocean in support of the Malaysian accident investigation. This assistance and expertise will be provided through the accredited representative mechanism of Annex 13.

In accordance with paragraphs 5.23 and 5.24 of Annex 13, on 1 April 2014, the Australian Transport Safety Bureau (ATSB) appointed an accredited representative and a number of advisors to the accredited representative (ATSB investigators). These investigators’ work will be undertaken as part of an External Investigation under the provisions of the Australian Transport Safety Investigation Act 2003.

The Malaysian Ministry of Transport is responsible for and will administer the release of all investigation reports into this accident. Information on the investigation is available from the following websites:

Any enquiries in respect of the ongoing investigation should, in the first instance, be directed to:

Malaysian Annex 13 Safety Investigation Team

Email: MH370SafetyInvestigation@mot.gov.my

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MH370 - Definition of Underwater Search Areas

Released: 3 December 2015


This report provides an update to the MH370 search area definition, described in previous ATSB reports. For background information, please see the ATSB publications MH370 - Definition of underwater search areas, 18 August 2014 and Flight Path Analysis Update, 8 October 2014 under the tabs on this web page.

Analysis of available data has been ongoing since the search for MH370 commenced. Initial results assisted the search and rescue mission, and later refinements have formed the basis for the underwater search areas.

The Australian Defence Science and Technology (DST) Group conducted a comprehensive analysis of the available data. The analysis used models of the Inmarsat satellite communications (SATCOM) data and a model of aircraft dynamics. Recorded meteorological data (wind and air temperature) were also modelled in the analysis. The SATCOM model was calibrated using SATCOM data and flight data from B777 flights including previous flights of the accident aircraft.

Validation experiments were conducted to ensure that predictions aligned with actual flight data. The output of the DST Group analysis was a probability density function (PDF) defining the probable location of the aircraft’s crossing of the 6th arc. These results were then extrapolated to the 7th arc. The analysis indicated that the majority of solutions only contained one significant turn after the last recorded radar data. DST Group have written a book called Bayesian methods in the search for MH370 detailing the entire analysis.

Performance analysis by Boeing produced a series of achievable ranges, with time intervals, for different cruise altitudes. It was noted that maintaining a constant altitude of FL350 or higher gave range values that closely matched the region on the arc corresponding to the DST Group analysis results. The DST Group and Boeing results were obtained independently and it is significant that they were in general agreement.

In contrast to the series of data points that were recorded from the SATCOM system, only the following indirect information was available to assist the ATSB in determining the end-of-flight scenario and therefore determine a search area width:

  • probable aircraft systems status
  • simulator results
  • review of previous accidents
  • glide distance.

The original ATSB underwater search area definition report published in August 2014 identified a width of 20 NM behind the arc and 30 NM forward of the arc as the priority search area width. This primary priority width has been adjusted to make it symmetrical about the arc (20 NM on both sides). The ATSB has also defined and prioritised additional search area widths.

The probability distribution of the location of the aircraft is shown in Figure 1.

Figure 1: Probability distribution of the location of MH370 Probability distribution of the location of MH370: Figure 1 is a graphical representation of the results from the DST Group analysis combined with the ATSB end-of-flight scenario. The colours in the area represent the different location probabilities as follows:  Low probability - Highest probability The yellow and pink lines are the 6th and 7th arcs respectively. The green line outlines the main area of interest representing approximately 90% of the PDF.

Ongoing work:

Any further evidence that becomes available, and may be relevant to refining the search area,will be considered.


Download report released 3 Dec 2015
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Download updated report of the flight pather analysis
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Released: 8 October 2014

Recent refinement to the analysis has given greater certainty about when the aircraft turned south into the Indian Ocean and has produced a better understanding of the parameters within which the satellite ground station was operating during the last flight of MH370. The latest analyses indicates that the underwater search should be prioritised further south within the wide search area for the next phase of the search. The ATSB has published MH370 – Flight path analysis update to supplement the previously released report MH370 – Definition of Underwater Search Areas, which describes the continuing work.

The schedule is the responsibility of the investigating state.

Download updated report of the flight pather analysis
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Download report MH370 - Definition of Underwater Search Areas
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MH370 - Definition of Underwater Search Areas


On 8 March 2014, flight MH370, a Boeing 777-200ER registered 9M-MRO, lost contact with Air Traffic Control during a transition of airspace between Malaysia and Vietnam. An analysis of radar data and subsequent satellite communication (SATCOM) system signalling messages placed the aircraft in the Australian search and rescue zone on an arc in the southern part of the Indian Ocean. This arc was considered to be the location where the aircraft’s fuel was exhausted.

A surface search of probable impact areas along this arc, coordinated by the Australian Maritime Safety Authority, was carried out from 18 March – 28 April 2014. This search effort was undertaken by an international fleet of aircraft and ships with the search areas over this time progressing generally from an initial southwest location along the arc in a north-easterly direction. The location of the search areas was guided by continuing and innovative analysis by a Joint Investigation Team of the flight and satellite-communications data. This analysis was supplemented by other information provided to ATSB during this period. This included possible underwater locator beacon and hydrophone acoustic detections.

No debris associated with 9M-MRO was identified either from the surface search, acoustic search or from the ocean floor search in the vicinity of the acoustic detections. The ocean floor search was completed on 28 May 2014.

Refinements to the analysis of both the flight and satellite data have been continuous since the loss of MH370. The analysis has been undertaken by an international team of specialists from the UK, US and Australia working both independently and collaboratively. Other information regarding the performance and operation of the aircraft has also been taken into consideration in the analysis.

Using current analyses, the team has been able to reach a consensus in identifying a priority underwater search area for the next phase of the search.

The priority area of approximately 60,000 km2 extends along the arc for 650 km in a northeast direction from Broken Ridge. The width of the priority search area is 93 km. This area was the subject of the surface search from Day 21-26.

Work is continuing with refinements in the analysis of the satellite communications data. Small frequency variations can significantly affect the derived flight path. This ongoing work may result in changes to the prioritisation and locale of search activity.


Updated: 18 August 2014

Since the public release of the report MH370 – Definition of Underwater Search Areas on 26 June 2014, the ATSB has received a number of queries about some of the technical details contained in the report. The queries have been made directly to the ATSB or through the Chief Commissioner’s blog, InFocus, on the ATSB website. 

As a result of the queries, the ATSB is today releasing an updated version of the report to clarify a number of technical aspects. The changes to the report are detailed in the Addendum on the inside cover.


Updated: 8 October 2014

Recent refinement to the analysis has given greater certainty about when the aircraft turned south into the Indian Ocean and has produced a better understanding of the parameters within which the satellite ground station was operating during the last flight of MH370. The latest analyses indicates that the underwater search should be prioritised further south within the wide search area for the next phase of the search. The ATSB has published MH370 – Flight path analysis update to supplement the previously released report MH370 – Definition of Underwater Search Areas, which describes the continuing work.


Download report MH370 - Definition of Underwater Search Areas
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Safety issues

AE-2014-054-SI-01 - AE-2014-054-SI-02 -  

Search and rescue information

There is relatively limited public and official information available about the process and outcomes of some searches. It is not an explicit part of the ICAO Annex 13 guidelines for inclusion in an accident investigation report. Similarly there is no Annex 12 requirement to publish or analyse search information. This limits the ability for researchers to determine the factors that help or hinder a search.

Safety issue details
Issue number:AE-2014-054-SI-01
Who it affects:International Civil Aviation Organization
Status:Safety action pending


Aircraft tracking

While there has been significant enhancements in the tracking of commercial aircraft in recent years there are some limitations to the improvements. The ICAO mandated 15-minute position tracking interval for existing aircraft may not reduce a potential search area enough to ensure that survivors and wreckage are located within a reasonable timeframe.

Safety issue details
Issue number:AE-2014-054-SI-02
Who it affects:Aircraft operators, aircraft manufacturers, and aircraft equipment manufacturers
Status:Safety action pending

General details
Date: 07 March 2014 Investigation status: Active 
Time: 1722 UTC  
Location   (show map):Southern Indian Ocean Investigation type: External Investigation 
State: International Occurrence type: Missing aircraft 
Release date: 03 October 2017 Occurrence class: Technical 
Report status: Pending Occurrence category: Technical Analysis 
 Highest injury level: Fatal 
Aircraft details
Aircraft model: 777-200ER  
Aircraft registration: 9M-MRO  
Operator: Malaysia Airlines  
Type of operation: Air Transport High Capacity 
Sector: Jet 
Departure point:Kuala Lumpur, Malaysia
Destination:Beijing, China
Related: MH370
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