The mystery of how Malaysia Airlines Flight MH370 flew into oblivion, and the challenge of finding new ways to track aircraft, will hang over the annual conference of airlines that opens Sunday in Doha.
The loss of the Malaysia Airlines plane, with 239 people on board, was a shock to the airline industry, and clouds the event in Doha just as it also celebrates 100 years of commercial aviation.
Aircraft being produced today for the next expected boom in traffic are scarcely comparable to the biplanes which carried mail or seaplanes which later assured many long-distance routes before the age of electronic navigation.
The main purpose of this 70th annual meeting, organised by the International Air Transport Association (IATA), is to enable its 240 members accounting for 84.0 percent of global air traffic to talk about business prospects for the sector.
But the three-day get-together will open under the shadow of the Boeing 777 airliner which took off from Kuala Lumpur on March 8 bound for Beijing, but disappeared leaving behind a trail of despair for relatives of the passengers and crew, muddle over what had happened, and mystery over where it had gone.
Various theories emerged about how and why the plane may have veered widely off course, and searches switched direction accordingly, but no debris has been found in the southern Indian Ocean where the aircraft is now believed to have looped far off course.
The drama also revealed to astonished public opinion that in an age of sophisticated civil and military radar scanning and of GPS satellite location and monitoring systems, an airliner can fly into apparent blind spots, leaving little or no trace.
This has led to calls for all airliners to be equipped at modest cost with extra emitters.
When IATA held its last annual meeting in Cape Town, South Africa, in 2013 one of the matters raised was poor air transport safety in Africa.
- Tracking by the minute -
This year the conference will focus on how to improve the tracking of aircraft using various technologies to monitor their movements or to ensure the transmission of flight data. It is likely to encourage various international initiatives on this.
The International Civil Aviation Organization has just formed a working group which by September is to come up with ways of tracking aircraft.
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At the European Aviation Safety Agency, executive director Patrick Ky said: "This meeting of IATA is particularly important in the context of the disappearance of Flight MH370."
He said: "We are mobilised to ensure that such a tragic event doesn't happen again."
At Air France, the director responsible for operations, Alain Bassil, said: "The disappearance of Flight MH370 is a landmark for airline companies as a whole ... The annual meeting of IATA is an opportunity to advance in the procedures for looking for an aircraft and providing emergency help in the event of an accident."
The French airline, the operator of an Airbus 330 airliner which plunged into the Atlantic Ocean on June 1, 2009, was slightly ahead on the issue, he said.
The company had extended the life of signals from the so-called black boxes of data carried on aircraft to 90 days to allow more time for investigators to locate a wreck.
It has also equipped its planes to automatically report their positions more frequently than most other airlines.
"Our airliners transmit their positions every ten minutes," he said, while the average at other airlines is 20 minutes.
"We have developed software so that the plane can report its position automatically, every minute, if it veers from its flight path or otherwise behaves in a way which does not correspond to that part of the flight path, such as a premature descent to a back-up airport."
IATA will also make its forecasts for profits by the sector this year.
In March, it adjusted its outlook down to $18.7 billion (13.7 billion euros) from $19.7 billion forecast previously, because of a rise in the price of fuel.
The place chosen for the meeting, in the Middle East where air traffic is booming, is also symbolic. This week a new airport was opened in Doha.
Last year, traffic in the region showed the biggest increase anywhere, expanding by 11.4 percent compared with an average figure of 5.2 percent.
In just over a decade, airlines in the Middle East have increased their share of world traffic from 4.0 percent to 9.0 percent. And traffic in the region is expected to grow at an average rate of 7.1 percent a year in the next 20 years compared with 4.7 percent for the sector globally.