Malaysia Airlines Flight 370

=== Southern Indian Ocean ===
[[File:MH370 SIO search.png|thumb|upright=2<!-- large enough to be at least somewhat readable; in line with MOS:IMAGESYNTAX -->|The shifting search zones for Flight 370 in the Southern Indian Ocean. The inset shows the path taken by the vessel ADV ''Ocean Shield'' operating a towed pinger locator, acoustic detections, and the sonar search. The underwater phase (both the wide area search and priority area) is shown in pink.|alt=A bathymetric map of the southeastern Indian Ocean and western Australia, with the locations of search zones, sonobouy drops, and calculated flight paths. An inset in the upper left shows the path of the ADV Ocean Shield which towed a Towed Pinger Locator and where it detected acoustic signals; the same inset also shows the seafloor sonar search performed in April–May 2014.]]
The emphasis of the search was shifted to the southern Indian Ocean west of Australia and within Australia's aeronautical and maritime Search and Rescue regions that extend to [[75th meridian east|75°E longitude]].<ref>{{cite web|title=Arrangements in Australia|url=https://www.amsa.gov.au/search-and-rescue/sar-in-australia/arrangements-in-australia/|website=Australian Maritime Safety Authority|access-date=12 November 2014|url-status=dead|archive-url=https://web.archive.org/web/20150224204938/http://www.amsa.gov.au/search-and-rescue/sar-in-australia/arrangements-in-australia/|archive-date=24 February 2015}}</ref><ref>{{cite web|title=National Search and Rescue Manual – June 2014 edition|url=http://natsar.amsa.gov.au/documents/NATSAR-Manual/Australian%20National%20SAR%20Manual%20June%202014%20FINAL.pdf|website=Australia Maritime Safety Authority|access-date=12 November 2014|page=231|archive-url=https://web.archive.org/web/20150412041944/http://natsar.amsa.gov.au/documents/NATSAR-Manual/Australian%20National%20SAR%20Manual%20June%202014%20FINAL.pdf|archive-date=12 April 2015|url-status=dead}}</ref> Accordingly, on 17&nbsp;March, Australia agreed to manage the search in the southern locus from [[Sumatra]] to the southern Indian Ocean.<ref name="20140317canberratimes"/><ref name="20140317thestar"/>

==== Initial search ====
From 18 to 27 March 2014, the search effort focused on a {{convert|315000|sqkm|abbr=on}} area about {{convert|2600|km|nmi mi|abbr=on}} southwest of Perth.<ref name="Search map 19 March"/> The search area, which Australian prime minister [[Tony Abbott]] called "as close to nowhere as it's possible to be", is renowned for its [[Roaring Forties|strong winds]], inhospitable climate, hostile seas, and deep ocean floors.<ref name="AutoVQ-17"/><ref name="Search map 18 March"/> Satellite imagery of the region was analysed;<ref>{{cite web|url=https://thewest.com.au/news/australia/perth-remote-sensing-firm-on-mh370-mission-ng-ya-368670|title=Perth remote sensing firm on MH370 mission|date=3 April 2014|website=The West Australian|access-date=10 December 2019|archive-date=7 December 2019|archive-url=https://web.archive.org/web/20191207035233/https://thewest.com.au/news/australia/perth-remote-sensing-firm-on-mh370-mission-ng-ya-368670|url-status=live}}</ref> several objects of interest and two possible debris fields were identified on images made between 16 and 26&nbsp;March. None of these possible objects were found by aircraft or ships.<ref name="BBC-satellite debris">{{cite news|title=Flight MH370: Images of ocean debris|url=https://www.bbc.com/news/world-asia-26662641|access-date=10 November 2014|publisher=BBC News|date=28 March 2014|archive-date=21 March 2015|archive-url=https://web.archive.org/web/20150321143007/http://www.bbc.com/news/world-asia-26662641|url-status=live}}</ref>

Revised estimates of the radar track and the aircraft's remaining fuel led to a move of the search {{convert|1100|km|nmi mi|abbr=on}} northeast of the previous area on 28&nbsp;March,<ref name="BBC_2014-03-28_b"/><ref name="NST(28 March)"/><ref name="CNN(28 March)"/> which was followed by another shift on 4 April.<ref name="JACC_2014-04-04_mr006">{{cite web|title=Search and recovery continues for Malaysian flight MH370 (4 April 2014 am)|url=http://www.jacc.gov.au/media/releases/2014/april/mr006.aspx|publisher=[[Joint Agency Coordination Centre]]|date=4 April 2014|access-date=6 May 2014|archive-date=5 May 2014|archive-url=https://web.archive.org/web/20140505071902/http://www.jacc.gov.au/media/releases/2014/april/mr006.aspx|url-status=live}}</ref><ref name="Search map 4 April">{{cite web|url=https://s3-ap-southeast-2.amazonaws.com/asset.amsa.gov.au/MH370+Day+18/Charts/2014_04_04_cumulative_search_handout.pdf|title=Incident 2014/1475 – search for Malaysia Airlines flight MH370 – area searched (4 April)|publisher=Australian Maritime Safety Authority|date=4 April 2014|access-date=12 April 2015|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304035159/https://s3-ap-southeast-2.amazonaws.com/asset.amsa.gov.au/MH370+Day+18/Charts/2014_04_04_cumulative_search_handout.pdf|url-status=live}}</ref> Between 2 and 17 April, an effort was made to detect the [[underwater locator beacon]]s (ULBs, informally known as "pingers") attached to the aircraft's [[flight recorder]]s, because the beacons' batteries were expected to expire around 7 April.<ref name="BBC_2014-03-31_a">{{cite news|last=Donnison|first=Jon|title=Malaysia flight MH370: No time limit on search, says Tony Abbott|url=https://www.bbc.co.uk/news/world-asia-26814929|work=BBC News|date=31 March 2014|access-date=8 May 2014|archive-date=3 April 2014|archive-url=https://web.archive.org/web/20140403095926/http://www.bbc.co.uk/news/world-asia-26814929|url-status=live}}</ref><ref name="British submarine">{{cite web |url=http://news.sky.com/story/1235477/royal-navy-submarine-joins-mh370-search |title=Royal Navy Submarine Joins MH370 Search |date=2 April 2014 |access-date=12 April 2015 |publisher=Sky News |archive-date=7 July 2015 |archive-url=https://web.archive.org/web/20150707163000/http://news.sky.com/story/1235477/royal-navy-submarine-joins-mh370-search |url-status=live }}</ref> Australian naval cutter [[ABFC Ocean Shield|ADV ''Ocean Shield'']], equipped with a [[towed pinger locator]] (TPL), joined China's ''[[Haixun 01]]'', equipped with a hand-held hydrophone, and the Royal Navy's [[HMS Echo (H87)|HMS ''Echo'']], equipped with a hull-mounted hydrophone, in the search.<ref name=ATSB />{{Rp|11–12}}<ref name="ATSB Final Report AE-2014-054"/>{{rp|36}}<ref name="BBC_2014-03-31_a"/><ref name=20140404IBT>{{cite web | url=http://www.ibtimes.com/malaysia-airlines-flight-mh370-towed-pinger-locators-deployed-underwater-hunt-black-1567381?ft=74gk7 | title=Malaysia Airlines Flight MH370: Towed Pinger Locators Deployed, Underwater Hunt For Black Box Launched With Hopes Of A Breakthrough | website=International Business Times | date=4 April 2014 | access-date=23 March 2018 | first1=Suman | last1=Varandani | archive-date=24 March 2018 | archive-url=https://web.archive.org/web/20180324041402/http://www.ibtimes.com/malaysia-airlines-flight-mh370-towed-pinger-locators-deployed-underwater-hunt-black-1567381?ft=74gk7 | url-status=live }}</ref><ref name="JACC_2014-04-04_mr007">{{cite web|title=Pinger locator equipment commences operation (4 April 2014)|url=http://www.jacc.gov.au/media/releases/2014/april/mr007.aspx|publisher=[[Joint Agency Coordination Centre]]|date=4 April 2014|access-date=6 May 2014|archive-date=31 May 2014|archive-url=https://web.archive.org/web/20140531173951/http://www.jacc.gov.au/media/releases/2014/april/mr007.aspx|url-status=live}}</ref> Operators considered the effort to have little chance of success<ref name="wday95224">{{cite web|url=http://www.wday.com/event/article/id/95224/group/News/ |title=Only days left before Malaysia airlines flight 370's black box dies |publisher=WDAY |date=30 March 2014 |archive-url=https://web.archive.org/web/20140407072117/http://www.wday.com/event/article/id/95224/group/News/ |archive-date=7 April 2014 |url-status=dead |access-date=13 July 2014 }}</ref> given the vast search area and the fact that a TPL can only search up to {{convert|50|mi2|order=flip|km2|abbr=on}} per day.<ref name="wday95224"/>

Between 4 and 8&nbsp;April, several acoustic detections were made that were close to the frequency and rhythm of the sound emitted by the flight recorders' ULBs; [[Search for Malaysia Airlines Flight 370#Underwater locator beacons|analysis of the acoustic detections]] determined that, although unlikely, the detections could have come from a damaged ULB.<ref name=ATSB />{{Rp|13}} A sonar search of the seafloor near the detections was carried out between 14&nbsp;April and 28&nbsp;May but yielded no sign of Flight 370.<ref name=ATSB />{{Rp|14}} In a March 2015 report, it was revealed that the battery of the ULB attached to Flight 370's flight data recorder may have expired in December 2012 and thus may not have been as capable of sending signals as would an unexpired battery.<ref>{{cite news |url=https://phys.org/news/2015-03-mh370-underwater-beacon-battery-expired.html |title=MH370 report: Underwater locator beacon battery had expired |work=phys.org |last=Ng |first=Eileen |date=8 March 2015 |access-date=7 July 2017 |archive-date=14 October 2017 |archive-url=https://web.archive.org/web/20171014234441/https://phys.org/news/2015-03-mh370-underwater-beacon-battery-expired.html |url-status=live }}</ref><ref>{{cite web |first=Samantha |last=Hawley |title=Malaysia Airlines MH370: Report finds battery powering locator beacon on black box expired in 2012, no red flags raised over crew or aircraft |date=8 March 2015 |access-date=8 March 2015 |website=Australian Broadcasting Corp. |url=http://www.abc.net.au/news/2015-03-08/mh370-report-says-black-box-locator-beacon-expired/6289462 |archive-date=8 March 2015 |archive-url=https://web.archive.org/web/20150308132611/http://www.abc.net.au/news/2015-03-08/mh370-report-says-black-box-locator-beacon-expired/6289462 |url-status=live }}</ref>

==== Underwater search ====
{{commons and category|Search for Malaysia Airlines Flight 370|Category:Search for Malaysia Airlines Flight 370}}
In late June 2014, details of the next phase of the search were announced;<ref>{{cite news|last1=Smyth|first1=Jamie|title=Search for Malaysia Airlines flight MH370 to resume in new area|url=http://www.ft.com/cms/s/0/912130e8-fd06-11e3-8ca9-00144feab7de.html#axzz3JS0bpHI4|access-date=18 November 2014|work=Financial Times|date=26 June 2014|archive-date=31 August 2014|archive-url=https://web.archive.org/web/20140831224222/http://www.ft.com/cms/s/0/912130e8-fd06-11e3-8ca9-00144feab7de.html#axzz3JS0bpHI4|url-status=live}}</ref> officials have called this phase the "underwater search" despite the previous seafloor sonar survey.<ref name=JACC-search>{{cite web|title=Search for MH370|url=http://www.jacc.gov.au/search/index.aspx|website=jacc.gov.au|publisher=Joint Agency Coordination Centre|access-date=14 December 2014|archive-date=20 June 2015|archive-url=https://web.archive.org/web/20150620180213/http://www.jacc.gov.au/search/index.aspx|url-status=live}}</ref> Continued refinement of the analysis of Flight 370's satellite communications identified a "wide area search" along the "7th arc"{{efn|name="7th arc"}} where Flight 370 was located when it last communicated with the satellite. The priority search area was in the southern extent of the wide area search.<ref name="Operational search update 8 Oct">{{cite web|title=MH370 Operational Search Update|url=http://www.jacc.gov.au/families/operational_reports/opsearch-update-20141008.aspx|website=Joint Agency Coordination Centre|access-date=12 November 2014|date=8 October 2014|archive-date=8 December 2014|archive-url=https://web.archive.org/web/20141208064243/http://www.jacc.gov.au/families/operational_reports/opsearch-update-20141008.aspx|url-status=live}}</ref> Some of the equipment used for the underwater search is most effective when towed {{convert|650|ft|order=flip|abbr=on}} above the seafloor at the end of a {{convert|6|mi|abbr=on|order=flip}} cable.<ref name="NYT-bathymetric survey">{{cite news|last1=Innis|first1=Michelle|title=Rugged Seabed Seen in New Maps Further Complicates Search for Malaysia Airlines Jet|url=https://www.nytimes.com/2014/10/07/world/asia/search-resumes-for-missing-malaysian-airliner.html|access-date=18 November 2014|work=The New York Times|date=6 October 2014|archive-date=27 October 2014|archive-url=https://web.archive.org/web/20141027123923/http://www.nytimes.com/2014/10/07/world/asia/search-resumes-for-missing-malaysian-airliner.html|url-status=live}}</ref> Available [[Bathymetry|bathymetric]] data for this region was of poor resolution, thus necessitating a bathymetric survey of the search area before the underwater phase began.<ref name="Operational search update 5 Nov">{{cite web|title=MH370 Operational Search Update|url=http://www.jacc.gov.au/families/operational_reports/opsearch-update-20141105.aspx|website=Joint Agency Coordination Centre|date=5 November 2014|access-date=5 December 2014|archive-date=11 March 2018|archive-url=http://webarchive.nla.gov.au/gov/20180311050517/http://www.jacc.gov.au/families/operational_reports/opsearch-update-20141105.aspx|url-status=live}}</ref> Commencing in May, the survey charted around {{convert|208000|sqkm|abbr=on}} of seafloor until 17&nbsp;December 2014, when it was suspended so that the ship conducting the survey could be mobilised in the underwater search.<ref name="JACC search update 7 Jan">{{cite web|title=MH370 Operational Search Update|date=7 January 2015|url=http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150107.aspx|website=Joint Agency Coordination Centre|access-date=8 January 2015|archive-date=10 January 2015|archive-url=https://web.archive.org/web/20150110070806/http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150107.aspx|url-status=live}}</ref>

The governments of Malaysia, China, and Australia made a joint commitment to thoroughly search {{convert|120000|sqkm|abbr=on}} of seafloor.<ref name="Operational search update 09 December 2015">{{cite web|title=MH370 Operational Search Update|url=http://jacc.gov.au/families/operational_reports/opsearch-update-20151209.aspx|website=JACC|access-date=9 December 2015|date=9 December 2015|archive-date=10 December 2015|archive-url=https://web.archive.org/web/20151210213135/http://jacc.gov.au/families/operational_reports/opsearch-update-20151209.aspx|url-status=live}}</ref> This phase of the search, which began on 6&nbsp;October 2014,<ref name="Operational search update 8 Oct" /> used three vessels equipped with towed deep-water vehicles that use side-scan sonar, multi-beam echo sounders, and video cameras to locate and identify aircraft debris.<ref name="WSJ-5th phase begins">{{cite news|last=Stewart|first=Robb M|title=Malaysia Airlines Flight 370 Search Reboots|url=https://online.wsj.com/articles/malaysia-airlines-flight-370-search-reboots-1412578236|access-date=8 October 2014|work=The Wall Street Journal|date=6 October 2014|archive-date=9 October 2014|archive-url=https://web.archive.org/web/20141009010007/http://online.wsj.com/articles/malaysia-airlines-flight-370-search-reboots-1412578236|url-status=live}}</ref> A fourth vessel participated in the search between January and May 2015, using an [[autonomous underwater vehicle|AUV]] to search areas that could not be effectively searched using equipment on the other vessels.<ref name="14 Jan 2015 Search update">{{cite web|title=MH370 Operational Search Update|url=http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150114.aspx|website=JACC|access-date=2 February 2015|date=14 January 2015|quote=Fugro Supporter is expected to arrive in the search area and commence search activities in late January. Fugro Supporter has been equipped with a Kongsberg HUGIN 4500 autonomous underwater vehicle (AUV). The AUV will be used to scan those portions of the search area that cannot be searched effectively by the equipment on the other search vessels.|archive-date=19 January 2015|archive-url=https://web.archive.org/web/20150119230517/http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150114.aspx|url-status=live}}</ref><ref name="JACC search update 28 Jan 2015">{{cite web|title=MH370 Operational Search Update|date=28 January 2015|url=http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150128.aspx|website=JACC|access-date=1 February 2015|archive-date=30 January 2015|archive-url=https://web.archive.org/web/20150130023357/http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150128.aspx|url-status=live}}</ref><ref name="13 May 2015 search update">{{cite web|title=MH370 Operational Search Update|url=http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150513.aspx|website=JACC|access-date=2 June 2015|date=13 May 2015|archive-date=17 May 2015|archive-url=https://web.archive.org/web/20150517124216/http://www.jacc.gov.au/families/operational_reports/opsearch-update-20150513.aspx|url-status=live}}</ref> Following the discovery of the flaperon on Réunion, the [[Australian Transport Safety Bureau]] (ATSB) reviewed its drift calculations for debris from the aircraft and, according to the JACC, was satisfied that the search area was still the most likely crash site.<ref name="Operational search update 5 August 2015" /> Reverse drift modelling of the debris, to determine its origin after 16 months, also supported the underwater search area, although this method is very imprecise over long periods.<ref name="Operational search update 5 August 2015" /> On 17&nbsp;January 2017, the three countries jointly announced the suspension of the search for Flight 370.<ref name="Search suspended"/><ref name="MH370 Joint Communique">{{cite web|title=MH370 Joint Communique|url=http://jacc.gov.au/media/communiques/2017/com005.aspx|website=JACC|date=17 January 2017|access-date=20 January 2017|archive-date=17 January 2017|archive-url=https://web.archive.org/web/20170117171757/http://jacc.gov.au/media/communiques/2017/com005.aspx|url-status=live}}</ref>