After the baffling disappearance in March of Flight MH370, critics accused the aviation industry of "dithering" over equipping jets with real-time tracking systems. Now, with another passenger plane lost, the call for action is becoming more insistent.

Tracking aircraft by satellite and live-streaming of black box data were cited as top priorities by industry insiders after the disappearance of Malaysia Airlines Flight 370 with 239 people on board. Its fate remains a mystery despite a long underwater search west of Australia.

Members of the International Civil Aviation Organization (ICAO) -- the UN's aviation body -- agreed in the aftermath of the incident to mandate real-time tracking.

But they did not set a timeline as airlines mulled the additional costs involved. Many carriers have been losing money for years.

Now, with the apparent loss of AirAsia Flight QZ8501 on Sunday off Indonesia, the calls for immediate changes have returned with vehemence.

The Airbus A320-200 carrying 162 people lost contact en route from Indonesia's second-largest city Surabaya to Singapore. An aerial search crew on Tuesday spotted apparent debris in the Java Sea.

Experts say while real-time tracking technology would not have prevented loss of life in the two incidents, it would have significantly streamlined search efforts.

Real-time tracking "won't save lives but recovering wreckage and the black boxes in a timely manner could lead to safety and operational changes that will save lives in the future", said Scott Hamilton, managing director of US aerospace consultancy Leeham Co.

- 'Tombstone mentality' -

In a scathing commentary, Hamilton accused the ICAO of "dithering since MH370 about mandating real-time tracking".

"Aviation regulators are infamous for their 'tombstone' mentality -- not requiring safety changes until people die," he wrote.

Some in the aviation industry complain about the high costs of adopting satellite-based technology, but critics such as Hamilton point out that airlines are simultaneously investing millions to offer passengers satellite-based broadband services.

US-based aviation consultant Robert Mann said airlines are "dodging action now" in the hope that a "future satellite-based (tracking) solution will be faster, better and cheaper in the late 2020s".

"I do not see the airline industry adopting real-time flight following unless mandated to do so," Mann told AFP, adding that in the maritime industry, satellite tracking has been required since 1988.

The ICAO says there are off-the-shelf real-time tracking solutions costing under $100,000 per plane. British satellite operator Inmarsat has offered a basic tracking service to all of the world's passenger airlines for free.

But some industry insiders say the focus should not solely be on the state-of-the-art tracking technology.

As was the case in the MH370 incident, authorities involved in the search for Flight QZ8501 did not immediately pick up signals from the aircraft's emergency locator transmitter -- mandatory in the industry for decades -- when the plane went missing.

"Even with MH370 the beacon did not go off. Why aren't we getting the beacon in large-scale incidents?" said Jakarta-based aviation consultant Gerry Soejatman.

"I am not saying it is a faulty system. The beacon (ELT) is the best thing we have at the moment. But we have to work on improving it," he said.

And some observers say criticism over the aviation industry's perceived inaction over tracking should be grounded in reality.

"Even if there had been consensus about real-time tracking after MH370, it was always going to take quite a long time to make the changes. Certainly not within one year," Terence Fan, an aviation expert at the Singapore Management University, told AFP.

Andrew Herdman, director-general of the Association of Asia Pacific Airlines, said ICAO efforts for an industry-wide adoption of real-time tracking "remain steady".

"Short- to medium-term efforts to enhance global tracking are ongoing. This also includes data-streaming black boxes," he said.

"At this moment, we really should be focusing on the search effort, and we should be cautious about linking the incident to the ongoing debate on flight tracking," he added.