An atmospheric research team from Gloucestershire has been monitoring the volcanic ash cloud which has grounded UK flights for a second day.
The team, part of the Swindon-based National Environment Research Council (NERC), took off from Gloucestershire Airport at Staverton on Thursday.
Accompanied by scientists from Oxford, it flew north to the edge of the plume, to collect speed and direction data.
A Dornier 288 plane was adapted to enable the team to take readings.
It was modified with small holes which suck in air, enabling experts to analyse its gas content.
The modifications also mean the team can closely monitor how close to the plume they are, enabling the plane to fly safely near to it.
They looked for evidence of sulphur dioxide – a characteristic gas exhaled by volcanoes which forms sulphuric acid, said Peter Purcell, head of NERC’s airborne research facilities.
“I don’t believe that anybody has really used an aircraft to sample the edge of these plumes before – it is actually very dangerous,” he said.
“If you fly into the ash and your engines stop, you crash.”
A series of canisters positioned under the plane’s wings measure particulates – shards of volcanic ash – in the atmosphere, he added.
Information gathered is expected to aid advice to the airports, as well as improving future forecasts.
The team was standing by on Friday for a second mission.
The grounding of all non-emergency flights from England’s airports – which began on Thursday morning – will remain in place until at least 0100 BST on Saturday, as the plume continues to drift across Britain.
The ash cloud resulted from an eruption in the Eyjafjallajoekull area of Iceland.
