The search of the missing plane has been suspended.Reuters

With just months left before the search for the missing Malaysia Airlines flight MH370 is expected to come to an end, the families of the passengers on board have reiterated their demand for the search to continue, ahead of the second anniversary of the plane's disappearance that will be marked Tuesday.

Apart from finding answers on the fate of the flight, the families have maintained that the search will also be in the interest of aviation safety to ensure such incidents are not repeated.

The disappearance of the plane remains one of the biggest aviation mysteries, with more facts remaining shrouded than what has come to light in the past two years.

Here's what we know so far:

Where is MH370?

On March 8, 2014, the Malaysia Airlines MH370 flight with 239 people on board disappeared into mystery, leaving no trace of what happened to the plane after it took off from Kuala Lumpur for Beijing. Despite an intensive multi-country search led by Australia in the last two years, small and isolated discoveries have been the only significant clues suggesting a possible plane crash in the Indian ocean.

But for the kin of the missing, such as Chennai resident KS Narendran whose wife Chandrika Sharma was among those on board, the most significant aspect of the search has been that it has not yielded any answer the bizarre event posed from the very beginning – what happened on the flight and where is the plane?

"Stray findings such as that of the flaperon and the recent object found in Mozambique give rise to speculations. But it is difficult to be optimistic about knowing what happened, especially since there has been an air of mistrust since the very beginning on what has been presented to the public," Narendran told International Business Times, India.

The Australian Transport Safety Bureau (ATSB), which is leading the search operations, has said "all the available data indicates the aircraft entered the sea close to a long but narrow arc of the southern Indian Ocean."

What have been the most significant findings in the last two years?

"The discovery of the flaperon at La Reunion is currently the only piece of debris that has been conclusively identified as coming from MH370," Daniel JT O'Malley, Communications Officer, Australian Transport Safety Bureau, told IBTimes India via email. "This discovery not only supported the understanding that the aircraft had come to rest in the Indian Ocean, but drift modelling by the CSIRO showed that ocean currents could have carried the flaperon from the current search area."

Last week, an object said to be of a Boeing 777 was found off the coast of Mozambique, further adding to speculations of MH370's probable crash in the Indian Ocean.

On Sunday, another object believed to be of the missing plane was found on the Reunion Island, where the flaperon was discovered last year. The second object was discovered by the same person who came across the flaperon on the same spot in the French Indian Ocean island last year, according to The Guardian

What is the cost of the search operation for MH370?

Australia, Malaysia and China are together funding the extensive underwater search for MH370. Australia has committed Australian $60 million to the underwater search, while China has committed Australian $20 million in assets and financial contribution, O'Malley said. Malaysia has committed assets and financial contribution to fund the balance of the cost of the underwater search, he added.

"It is expected that the underwater search may cost up to [Australian] $180 million," the ATSB official said.

When will the search end? Is the plane likely to be found?

Australia, along with Malaysia and China, said that if the search of the 120,000 square kilometres of the demarcated area, which it said is likely to be completed "around the middle of the year," does not throw up any credible information, the search area will not be expanded.

However, Australian officials have said that with all evidence pointing to the current search area, the plane is likely to be found in the remaining area in the Indian Ocean.

"It is as likely on the last day [of the search] as on the first that the aircraft would be there. We've covered nearly three-quarters of the search area, and since we haven't found the aircraft in those areas, that increases the likelihood that it's in the areas we haven't looked at yet," Martin Dolan, head of the ATSB search team for MH370, told The Guardian.

"If the aircraft is in the search area, we are confident of finding it," O'Malley told IBTimes India.

What are the demands of the passengers' kin?

With little headway made in two years in determining what happened to MH370, passengers' families are worried that the search may end in the next few months, before anything significant emerges. 

Narendran is among those calling for the search to be continued till the plane is found.

"We have urged that the search not be abandoned. The argument of funds crunch is baseless. I think that staying committed with the search for a longer period is desirable," the Indian said before he left for Kuala Lumpur to mark the anniversary with the kin of other passengers.

Other family members also raised the demand during a remembrance meet in Kuala Lumpur Sunday.

"We can get compensation, but what is more important is that we find the truth. I don't want to give up on this," Chinese national Bai Chuan Fu, whose wife was also on board the flight, told the Star Online.

Voice 370, an international network of families of those on board, started an online petition to push for the search to continue, after it issued a statement last week calling for the "search to go on."

"We, the families of flight MH 370 through our family association, Voice370, in our call to all those with responsibility for the search and investigation, to not only continue the search until it provides the answers the world and the families demand, but to diversify that search and show the world that no stone really is being left unturned in the aftermath of this unprecedented disaster," the group said in its petition.