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· ‘Good night’ – Last words of MH370

The search for Malaysia Airlines Flight 370 has rekindled a debate over the iconic “black box” flight recorder and whether it’s time for aircraft to start live-streaming in-flight data in real time.

Civil aviation industry sources agree the technology exists for commercial airliners to immediately relay via satellite vital technical information otherwise compiled by a flight data recorder in the course of a flight.

But it’s another question whether airlines, forever struggling to keep down costs in a highly competitive business, want to front up the money involved – or even if it’s truly worth the expense.

Former Russian president Boris Yeltsin and a black box from a Korean plane shot down by Soviet jets.

“There are no technical barriers … and the cost barriers can be addressed,” said Peter Goelz, a former managing director of the National Transportation Safety Board (NTSB), the US government agency that investigates major aviation accidents.

“But the reality is that air carriers don’t want to do anything unless they’re ordered to do it,” he told AFP.

Commercial airliners typically carry two black boxes, which in fact are bright orange. One monitors cockpit conversations, the other records a vast array of technical data from airspeed to engine performance.

Whenever a crash occurs, investigators scramble to recover both devices – and if the tragedy happens on terra firma, they typically find them in short order.

At sea, however, it’s another story.

By then investigators already had a vague clue what might have happened thanks to the doomed flight’s Aircraft Communications Addressing and Reporting System (ACARS), a digital datalink for brief text messages.

It puts out limited information about location and airspeed – but nothing compared with the several thousand parameters that a black box can monitor during the course of a flight.

Malaysia Airlines has said all its aircraft are ACARS-equipped, but it has so far declined to release whatever data it got from Flight 370.

Twelve years ago, US avionics manufacturer L-3 estimated it would cost $US300 million ($A333.63 million) a year for a global airline to transmit flight data in real time, Bloomberg Businessweek magazine reported.

The main hurdle is getting airlines to invest in such systems. Goelz said the onus is on governments to make them mandatory, as in the case of mid-air collision avoidance systems and smoke detectors in cargo holds.

Families reject cash offer

Relatives of Chinese passengers on board missing Malaysia Airlines flight MH370 have declined to accept money from the airline as distrust and frustration at the carrier mounts.

The airline said on Tuesday it had offered “financial assistance” of 31,000 yuan ($A5500) to the family of each missing traveller.

Grieving relatives have rejected money from Malaysia Airlines. Photo: AAP

But a relative of one of the passengers, from east China’s Shandong province, said: “We’re not really interested in the money.”

“It is all about the people – the people on the plane. We just want them back,” she said at the Beijing hotel where relatives and friends of many of the 153 Chinese passengers – more than two-thirds of those on board MH370 – were waiting anxiously for news.

Ignatius Ong, leader of the Malaysia Airlines (MAS) response team in China, confirmed that the offer had not been taken up.

But he denied the relatives had rejected it, saying they had asked the airline to “review” the terms of the acceptance form.

“There are certain items where there will be a difference of opinion,” he added. “These are very difficult times and we also appreciate that at this time a lot of people are frustrated.”

Relatives have endured days of anxious waiting under an intense media spotlight and some appeared to begin to accept that their loved ones may not have survived.

“We are mentally prepared for the worst,” said one woman surnamed Cao, who said that her husband’s brother had been on board as part of a group accompanying Chinese artists to an exhibition in Malaysia.

AFP