Search planes found no sign of the missing Malaysia Airlines aircraft in an area where satellite images had shown debris.
The Malaysian prime minister on Monday cited analysis by British satellite company Inmarsat and the UK's Air Accidents Investigation Branch (AAIB) as the source of information that allowed authorities to narrow down the location of Malaysia Airlines flight MH370's possible crash site to a corridor a couple of hundred miles wide.
The analysis follows fresh examination of eight satellite "pings" sent by the aircraft between 1.11am and 8.11am Malaysian local time on Saturday March 8, when it vanished from radar screens.
Prime Minister Najib Razak said: "Based on their new analysis, Inmarsat and the AAIB have concluded that MH370 flew along the southern corridor, and that its last position was in the middle of the Indian Ocean, west of Perth.
"This is a remote location, far from any possible landing sites. It is therefore with deep sadness and regret that I must inform you that, according to this new data, flight MH370 ended in the southern Indian Ocean."
He added that they had used a "type of analysis never before used in an investigation of this sort".
The new method "gives the approximate direction of travel, plus or minus about 100 miles, to a track line," Inmarsat ​senior vice-president for external affairs Chris McLaughlin told Sky News. "Unfortunately this is a 1990s satellite over the Indian Ocean that is not GPS equipped. All we believe we can do is to say that we believe it is in this general location, but we cannot give you the final few feet and inches where it landed. It's not that sort of system."
No compulsory direction and distance reporting
McLaughlin told CNN that there was no further analysis possible of the data. "Sadly this is the limit. There's no global decision even after the Air France loss [in June 2009, where it took two years to recover the plane from the sea] to make direction and distance reporting compulsory. Ships have to log in every six hours; with aircraft travelling at 500 knots they would have to log in every 15 minutes. That could be done tomorrow, but the mandate is not there globally."
Since the plane disappeared more than two weeks ago, many of the daily searches across vast tracts of the Indian Ocean for the missing aircraft have relied on Inmarsat information collated halfway across the world from a company that sits on London's Silicon Roundabout, near the Old Street tube station.
Using the data from just eight satellite "pings" after the plane's other onboard Aircraft Communications Addressing and Reporting System​ (ACARS) automatic tracking system went off at 1.07am, the team at Inmarsat was initially able to calculate that it had either headed north towards the Asian land mass or south, towards the emptiest stretches of the India Ocean.
Inmarsat said it had done new calculations yesterday on the limited data which it received from the plane to come to its conclusion. McLaughlin told CNN that it was a "groundbreaking but traditional" piece of mathematics which was then checked by others in the space industry.
The company's system of satellites provide voice contact with air traffic control when planes are out of range of radar, which only covers about 10% of the Earth's surface, and beyond the reach of standard radio over oceans. It offers automatic reporting of positions via the plane's transponders. It is possible to send route instructions directly to the cockpit over a form of text message relayed through the satellite.
Inmarsat was set up in 1979 by the International Maritime Organisation to help ships keep in touch with the shore or call for emergency assistance no matter where they were, and has provided key satellite data about the last movements of flight MH370. Even as the plane went off Malaysian air traffic control's radar on March 8, Inmarsat's satellites were "pinging" the aircraft. A team at the company began working on the possible directions that the plane could have gone in, based on the responses it got. One pointed north; the other, south.
Inmarsat made technical adviser
But it took three days for that data to be passed on officially to the Malaysian authorities; apparently to prevent similar delays in future, three days later Inmarsat was officially made "technical adviser" to the AAIB in its investigation into MH370's disappearance.
Inmarsat's control room in London, like some of its other 60 locations around the world, looks like a miniature version of Nasa: a huge screen displaying the positions of its 11 geostationary satellites and dozens of monitors used to control and correct their positions. A press on a key can cause the puff of a rocket on a communications satellite 22 236 miles away and nudge its orbit a few inches this way or that.
More prosaically, Inmarsat's systems enable passengers to make calls from their seats and connect to the internet via wi-fi while flying thousands of feet in the air.
If the plane has its own "picocell", essentially a tiny mobile phone tower set up inside the plane, then that can be linked to the satellite communications system and enable passengers to use their cellphones to make calls routed through the satellite.
After its creation, Inmarsat's maritime role expanded rapidly to providing connectivity for airlines, the media, oil and gas companies, mining and construction in remote areas, and governments.
Privatised at the end of the 1990s, it was floated on the stock market in 2004 and now focuses on providing services to four main areas: maritime, enterprise (focused on businesses including aviation), civil and military work for the US government, and civil and military work for other governments. The US is the largest of its government clients, generating up to a fifth of its revenues of around £1-billion annually. The firm employs about 1 600 staff. – © Guardian News and Media 2014