Space engineers compared the satellite handshake “pings” from missing jet MH370 with other tracked commercial flights to determine it had crashed into the middle of the Indian Ocean.
Malaysian Prime Minister Najiv Razak on Monday revealed that analysis “never before used in an investigation of this sort” had shown the Malaysian airliner had crashed into the southern Indian Ocean.
That analysis was undertaken by mobile communications company Inmarsat, which provides satellite data for Malaysia Airlines.
Even though the plane’s transponder and ACARS system were turned off, the company’s box on the Boeing 777 – equivalent to a mobile phone handset – stayed on and was polled every hour by Inmarsat’s satellite.
The British company initially looked at the amount of time these handshake pings took to travel from the plane to its satellite 22,000 miles above the equator to determine the aircraft was moving along either a north or south corridor.
It passed on that discovery on March 11.
But space scientists continued to refine the model looking at the so-called doppler effect.
That’s the way radio waves contract and expand as they are going to and from the satellite.
“They’ve tested it off against a number of other aircraft known flights and come to the conclusion that only the southern route was possible,” Inmarsat senior vice president Chris McLaughlin told Sky News on Monday.
“We refined that with the signals we got from other (777) aircraft and that then gives you a very, very good fit.
“Previous aircraft provided a pattern and that pattern to the south is virtually what we got in our suggested estimates.
“So the fit is very, very strong.”
Mr McLaughlin said the company was relying on a 1990s satellite over the Indian Ocean that wasn’t GPS equipped.
But scientists could work out the approximate direction of travel “plus or minus 100 miles to a track line”.
“All we can do is to say we believe it is in this general location.
“We can not give you the final few feet and inches of where it landed. It’s just not that sort of system.”
While the company was able to work out where the last ping was sent from, the aircraft likely still had some fuel remaining.
But it would have run out before the next automated handshake.
Inmarsat has been appointed a technical advisor to the UK Air Accident Investigation Branch.
It passed on the new analysis after it was peer-reviewed by other experts in the UK space industry and compared with Boeing.
Mr McLaughlin said systems that kept track of a plane’s precise location should be mandated world-wide “and it could be delivered tomorrow”.