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.