Device detects ash cloud from the sky

Scientists have been testing new technology over Mount Etna, which they hope will help pilots detect ash cloud density.

If follows the eruption of Iceland's Eyjafjallajokull volcano in April last year, which led to the closure of most of European airspace.

Upto 100,000 flights were cancelled in the course of one week and millions of passengers were grounded.

The device will now be put through its paces on an Airbus passenger flight over the Pacific.

The BBC's Richard Lister reports.