Image copyright Reuters Image caption Distress calls from ships are already relayed free of charge over Inmarsat's global network

UK satellite operator Inmarsat is to offer a free, basic tracking service to all the world's passenger airliners.

The offer follows the case of Malaysia Airlines flight MH370, which disappeared without trace on 8 March.

It was very brief electronic "pings" from Inmarsat equipment on the lost plane that prompted investigators to look for wreckage in the Indian Ocean.

Inmarsat says the free service it is offering would carry definitive positional information.

It would see a plane determine its location using GPS and then transmit that data - together with a heading, speed and altitude - over Inmarsat's global network of satellites every 15 minutes.

"Our equipment is on 90% of the world's wide-body jets already. This is an immediate fix for the industry at no cost to the industry," Inmarsat senior vice-president Chris McLaughlin told BBC News.

Cost is one of the reasons often cited for the reluctance of airlines to routinely use satellite tracking.

The London-based company announced its offer ahead of a conference on aircraft tracking being hosted by the International Civil Aviation Organization (ICAO) in Montreal, Canada, on Monday.

Both ICAO and the International Air Transport Association (IATA), the trade association for the world's airlines, are currently considering how best to respond to the loss of MH370.

Many observers were incredulous that a Boeing 777 could simply vanish, that its identification systems could be deliberately disabled in the cockpit, and that once the aircraft flew beyond the range of radar it was essentially invisible.

Investigators' only clue to MH370's possible whereabouts was a series of hourly electronic "handshakes" made between Inmarsat equipment onboard the plane and ground stations that were automatically checking to see if a satellite connection was still open.

Experts had to use frequency analysis techniques on these pings to derive some approximate positional information.

This is far from ideal, so Inmarsat proposes that, at bare minimum, all passenger jets regularly transmit definitive data over its network.

The satellite operator would carry the cost, anticipated to be about $3m a year.

It already does something similar in the maritime sector. All distress calls from ships are relayed over its network free of charge.

The company would hope to recoup costs as airlines moved to take up some of its premium services. "But we would keep that basic tracking service free of charge," said Mr McLaughlin.

A number of organisations have put forward proposals in recent weeks to try to prevent a repeat of a MH370-type mystery.

Just last Tuesday, the European Aviation Safety Agency called for the power systems on "black box" flight recorders to be made to work underwater for at least 90 days, not the current 30 days.

This would have given search teams more time to pinpoint transmissions on the Indian Ocean floor.

The agency also said the minimum recording duration of the cockpit voice recorder should be increased to 20 hours from the two hours currently demanded.

The fear is that the MH370 voice recorder, even if it is recovered, will have overwritten key information several times.

Search teams continue to scour the Indian Ocean for any sign of the missing Malaysia Airlines jet.

The Australian defence vessel Ocean Shield, which carries a sophisticated underwater robot, has re-joined the hunt after several days of relief and resupply in the port city of Rockingham, Western Australia.

The official leading the hunt for the missing airliner says a full search of the suspected crash area could take up to a year.

Image copyright Getty Images Image caption The Ocean Shield left port this weekend to resume the search

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos