Officials who reassessed evidence from the disappearance of Malaysia Airlines flight MH370 have designated an additional 25,000km² search area north of the area so far investigated.
A re-examination of satellite communications data and drift analysis based on aircraft debris found along the African littoral have suggested “a remaining area of high probability between latitudes 32.5°S and 36°S along the seventh arc,” says the Australian Transport Safety Bureau (ATSB).
The “seventh arc” is where the aircraft, a Boeing 777-200ER registered 9M-MRO, transmitted its final satellite communication on 8 March 2014.
The ATSB report is based on the outcome of a ‘first principles review’ held from 2-4 November in Canberra. Participants in the review included government officials and experts from industry.
“There is a high degree of confidence that the previously identified underwater area searched to date does not contain the missing aircraft,” says the ATSB.
“Given the elimination of this area, the experts identified an area of approximately 25,000km² 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 the analysis to date, would be exhausted.”
The underwater search has resulted in hundreds of contacts, but only two ‘high interest’ contacts. Closer examination of these found a timber shipwreck and a rock field. Overall, 74 sonar contacts were investigated, but all were eliminated as having any relationship to MH370.
In determining the additional search area, the review team reconsidered the lateral aircraft autopilot control modes the aircraft may have been flying in.
Initially, satellite data suggested the aircraft was in ‘constant true track’ or ‘lateral navigation’ (LNAV). These modes would have favoured the southern end of the search area, but since these areas have been searched without finding the aircraft, other control modes indicating that the aircraft is in the northern portion of the search zone are now favoured.
“During the first principles review meeting, flight crew with extensive experience on the aircraft type indicated that the aircraft is usually flown in the LNAV or CMH (constant magnetic heading) lateral control modes. This information, combined with the results from the areas already searched, increase the likelihood in the northern section of the probability map.”
In addition, drift analysis of aircraft debris that washed up on the western edge of the Indian ocean also points to a more northern search area. Overlaying this with satellite communications data helped determine the possible new search area.
The announcement comes as the existing search is down to one ship, the Fugro Equator, which is expected to conclude its efforts in early 2017. In all, about 120,000km² has been searched.
MH370 disappeared while operating the Kuala Lumpur-Beijing flight, with all 239 people aboard the aircraft lost.
Apart from scattered debris washed up on the east coast of Africa, no physical trace of the aircraft has been located.