MH370 search areas planning map
Malaysia Airlines Flight MH370 underwater search areas planning map. Australian Transport Safety Bureau

The underwater search for missing Malaysia Airlines Flight MH370 will move about 500 miles farther south in the Indian Ocean making the area the focus of the next phase of the long-running search, authorities said Wednesday. The Australian Transport Safety Bureau, or ATSB, also published an updated flight path analysis to explain the move.

The search for the Boeing 777, which disappeared on March 8 with 239 people on board, resumed after a four-month break and is expected to take another year. The Fugro Discovery search vessel will scan the ocean floor in the new search area beginning Oct. 11, while the Fugro Equator, another search vessel, will be mobilized after a bathymetric map of the ocean floor is completed at the end of this month, ATSB announced.

“Recent refinement to the analysis has given greater certainty about when the aircraft turned,” the ATSB said, in a statement. “The underwater search should be prioritized further south.”

According to the ATSB's updated analysis, it is now believed that the missing jetliner is within the seventh arc, which is the extreme southern limit of the search zone, calculated based on estimates of the maximum range cruise, or MRC, of the jetliner. The ATSB said that a thorough analysis indicated that the aircraft "may be located within relatively close proximity to the arc,” although it could be farther south than initially thought.

"The simulator activities involved fuel exhaustion of the right engine followed by flameout of the left engine with no control inputs," ATSB said, in an update on the flight path analysis.

"This scenario resulted in the aircraft entering a descending spiralling low bank angle left turn and the aircraft entering the water in a relatively short distance after the last engine flameout."

On Monday, GO Phoenix -- a vessel contracted by the Malaysian government -- commenced the underwater search operation at the seventh arc.

“The vessel is expected to continue operations for around 12 days before sailing to Fremantle to be resupplied,” the Joint Agency Coordination Centre said, in a statement.

ATSB also said that the conditions in the search area, which lies in a remote part of the southern Indian Ocean known for rough weather, are expected to be good for the next four days. Malaysia and Australia are jointly funding the current phase of the search operation, which has entered its seventh month with no concrete clues about the whereabouts of the plane.