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Ash hitting a jet engine causes sand particles to melt and molten glass to form on turbine blades, stopping it dead, a BBC test has revealed.

Bang Goes The Theory presenter and scientist Jem Stansfield showed how a jet engine needs fresh air flowing through it to create thrust.

He said volcanic ash particles could bring turbine blades to a standstill, and there is only one way to get the blades moving again - turn the engine off.

Learn more from Bang Goes The Theory or watch the programme on iPlayer.

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