How did the AAIB assist in locating MH370?
The following statement has just been released today by the Prime Minister of Malaysia, in relation to the AAIB:

This evening I was briefed by representatives from the UK Air Accidents Investigation Branch (AAIB). They informed me that Inmarsat, the UK company that provided the satellite data which indicated the northern and southern corridors, has been performing further calculations on the data. Using a type of analysis never before used in an investigation of this sort, they have been able to shed more light on MH370's flight path.
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.
We will be holding a press conference tomorrow with further details. In the meantime, we wanted to inform you of this new development at the earliest opportunity. We share this information out of a commitment to openness and respect for the families, two principles which have guided this investigation.
Malaysia Airlines have already spoken to the families of the passengers and crew to inform them of this development. For them, the past few weeks have been heartbreaking; I know this news must be harder still. I urge the media to respect their privacy, and to allow them the space they need at this difficult time.

It's not a &quot;new technology&quot; per se, but a new form of analysis. You might have heard recently that the aircraft responded to hourly &quot;pings&quot; from a satellite:

British satellite company Inmarsat immediately began doing calculations based on a series of hourly &quot;pings,&quot; as the plane and one of the company's satellites tried to communicate with each other.
Triangulating those pings seems to have given Inmarsat a pretty good idea of where the plane went, along one of two routes, to the north and to the south.


Here is some further information:

About three hours after Flight MH370 went missing, Inmarsat, a British-based satellite company, began tracking the Boeing 777 through an on-board data system called Aero Classic. Every hour, Inmarsat's satellites would try to communicate with the aircraft, pinging it with a computerized question asking, in effect, &quot;Are you there?&quot;
For several hours, Flight MH370 responded &quot;Yes, I am,&quot; notifying engineers on the ground with a so-called handshake that the plane was still powered up.
Using that series of pings, Inmarsat engineers and other analysts were able to piece together two broad, arcing regions where the plane could have been located when it last communicated with the satellite.
&quot;Our engineers looked at the time between the handshakes, and they realized that the object wasn't stationary under a satellite but moving away from it,&quot; Christopher McLaughlin, senior vice president of Inmarsat, said Thursday. &quot;Over time, the engineers here recognized that there were a number of data points and that it had flown for several hours. We didn’t know if it was on the northern or southern corridor.&quot;

More information on how Inmarsat determined MH370 flew along the Southern corridor specifically, will likely be released tomorrow at the press conference (as mentioned in Najib Razak's statement), which I gather is the information you're looking for.