A high concentration of ash ingested by a jet engine can become molten and cause engine failure, which is why planes are not allowed to fly through the cloud.

高浓度的火山灰一旦被吸入喷气发动机就会融化，并且造成引擎故障，因此喷气式飞机是不允许在火山灰云层中穿行的。

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The flight ban was imposed because in the high temperatures of an engine turbine, ash can turn to molten glass and cripple the engine.

禁航是因为涡轮发动机产生高温，火山灰会熔化玻璃和削弱发动机。

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Besides lava flows, etna produces an almost constant, rhythmic discharge of steam, ash and molten rock.

除了熔岩流，埃特纳也几乎稳定、有节奏地喷发蒸汽、火山灰和熔融的岩石。

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Ash had clogged the engines, which only restarted when enough of the molten ash solidified and broke off.

BBC: When volcanic ash stopped a Jumbo at 37,000ft