KUALA LUMPUR - The search for missing Malaysia Airlines Flight MH370 is now focused on the southern Indian Ocean in an area covering 460,000sq nautical miles.
Acting Transport Minister Datuk Seri Hishammuddin Hussein confirmed that the search in the northern corridor had been called off following conclusive evidence that the aircraft had ended in the southern Indian Ocean.
"We are now working to further narrow down the search area, using the four methods I mentioned previously: gathering information from satellite surveillance, analysis of surveillance radar data, increasing air and surface assets, and increasing the number of technical and subject matter experts," he told the daily press conference here yesterday.
He said the search for the aircraft's black box will be intensified with the American Towed Pinger Locator - an instrument that can help locate the black box - expected to arrive in Perth today. The instrument will be fitted on Australian ship Ocean Shield.
On the assets deployed, Hishammuddin said two South Korean aircraft, six Chinese ships and the HMAS Success were in the search area.
Prime Minister Datuk Seri Najib Tun Razak announced on Monday that new analysis of satellite data by Inmarsat and the UK Air Accidents Investigation Branch concluded that MH370 had ended in the southern Indian Ocean.
Hishammuddin said Inmarsat recently developed an innovative technique which considers the velocity of the aircraft relative to the satellite.
"Depending on this relative movement, the frequency received and transmitted will differ from its normal value in much the same way that the sound of a passing car changes as it approaches and passes by. This is called the Doppler Effect.
"The Inmarsat technique analyses the difference between the frequency that the ground station expects to receive and one that is actually measured.
This difference is the result of the Doppler Effect and is known as the Burst Frequency Offset.
"The Burst Frequency Offset changes depending on the location of the aircraft on an arc of possible positions, its direction of travel, and its speed," Hishammuddin said.
To ensure the theory was accurate, he said, Inmarsat had checked its predictions using information from six other Boeing 777 aircraft flying on the same day in various directions. "The theory had been proven accurate."
"The analysis showed poor correlation with the northern corridor, but good correlation with the southern corridor, and depending on the ground speed of the aircraft, it was then possible to estimate positions at 0011 UTC, at which the last complete handshake took place.
"There is evidence of a partial handshake between the aircraft and groundstation at 0019 UTC. At this time this transmission is not understood and is subject to further ongoing work.
"No response was received from the aircraft at 0115 UTC, when the groundearth station sent the next log on/log off message.
"Therefore, sometime between 0011 UTC and 0115 UTC the aircraft was no longer able to communicate with the ground station."
He said the final position of the aircraft needed to be determined by an international working group comprising agencies with expertise in satellite communications and aircraft performance.