The first anniversary of the disappearance of Malaysia Airlines flight MH370 will be marked on 8 March 2015. Although the Australian Transport Safety Bureau continues to lead the multinational team searching the southern Indian Ocean seabed, no trace of the missing Boeing 777 has been found.

The ATSB is in discussions with its Malaysian and Chinese search partners on how long the search should continue before being abandoned in the event that no wreckage from the aircraft is discovered. "I do reassure the families of our hope and expectation that the ongoing search will succeed,” Australian Prime Minister Tony Abbot told parliament in Canberra on 5 March. “I cannot promise that the search will go on at this intensity forever, but we will continue our very best efforts to resolve this mystery and provide some answers." This followed a statement a few days earlier by Deputy Prime Minister Warren Truss who said: "We clearly cannot keep searching forever."

The reasoning behind these statements becomes clear when the disappearance of MH370 is contrasted with another recent aircraft loss over a huge ocean. When Air France flight 447, an Airbus A330, went missing over the South Atlantic in 2009 it was following its flight planned route, and its position when communications contact was lost was fairly accurately known. Within 48h of its disappearance, search aircraft and ships found floating wreckage, confirming the loss and providing some hope that the wreck would eventually be located. From that point, however, it still took two years to find the main wreckage and the flight recorders on the seabed.

But in the case of MH370 the aircraft was not following a flight planned route. Malaysian military radar showed it departing dramatically from its planned route from Kuala Lumpur to Beijing when it almost doubled back on its track over the Gulf of Thailand, heading west over the Malaysian peninsula and turning northwest to follow the Malacca Strait. It was last seen on Malaysian military radar heading out over the Andaman Sea.

After that, MH370 is known to have flown for about another 7h without any surveillance or communication. Analysis of periodic satellite datalink “handshake” signals from the aircraft led authorities such as the ATSB to conclude that the aircraft had turned onto a southerly heading soon after going off radar, but the precise track and speed could not be deduced.

Boeing 777 captain Simon Hardy contacted Flightglobal in November last year with a mathematical calculation revealing the southbound track probably adopted by MH370, and Flightglobal published his thesis in mid-December. In the intervening three months no-one – including the ATSB – has challenged Hardy’s calculations, which make complete navigational sense when reverse-engineered back to the point at which MH370 was last seen. Hardy’s proposition for the final location of MH370 is close to, but not within, the core search area being covered by the ATSB-led team working with the Joint Agency Coordination Centre (JACC) in Canberra, Australia.

So the current situation in the search for MH370 remains that although the existing accepted theories all point in a similar direction, there are no certainties.

The JACC recently released details of oceanic search plans involving four specialist ships operating out of Fremantle in Western Australia. The JACC said that GO Phoenix is currently in the search area conducting underwater search operations; Fugro Discovery arrived in the search area on 25 February and began underwater search operations; Fugro Equator arrived the following day, and Fugro Supporter joined them in early March. At that time, the JACC said, 40% of the “priority zone” had been searched.

Eight days after MH370 went missing, Flightglobal reported: “If the aircraft went north it will be found one day. If it went south there is no guarantee it will ever be found in the vastness of the southern Indian Ocean.” That remains true.

The only concrete change in aviation procedure that has been decided as a result of the MH370 disappearance is a resolution, passed at ICAO Montreal on 6 February, to adopt a new 15min flight tracking standard for commercial aircraft. This will enable automatic dependent surveillance of aircraft in oceanic and other areas where there is no radar coverage, making them easier to find if they go missing.

Inmarsat says it will work with Qantas and Virgin Australia as well as Airservices Australia to prepare for implementation of this resolution. The operational concept for the tracking system trial will be developed using automatic dependent surveillance-contract (ADS-C) satellite technology in Australia’s oceanic regions. ADS-C provides air traffic controllers with a frequently-updated surveillance picture of their oceanic airspace beyond radar coverage.

Airservices Australia says it will be the first ANSP to test the ICAO standard using Inmarsat’s global flight-tracking ADS-C messaging service. Inmarsat says some 11,000 commercial passenger aircraft are already equipped with an Inmarsat satellite connection, representing more than 90% of the world’s long-haul commercial fleet.

Get all the latest on the MH370 search here