Vulcano ash: First official report by DLR (german counterpart of NASA) released.

A successful Falcon measurement flight was performed on 19 April 2010 for probing plumes over Germany from the Iceland Eyjafjallajökull volcano eruption. Layers of volcanic ash were detected by Lidar and probed in-situ with aerosol instruments. Under suitable viewing conditions, the ash layer was visible as a brownish layer to the observer. The horizontal and vertical distributions of the volcano layers were variable. In the plume layers particles larger than 3μm were detected at concentrations, not present in the free troposphere during unpolluted conditions. The concentrations of large particles measured in the volcano layers are comparable to concentrations measured typically in Saharan dust plumes but smaller compared to particle concentrations in the polluted boundary layer. An estimation of the particle mass concentration in the volcanic ash plume probed as part of a vertical profile over Leipzig at about 4 km altitude yield 60 μg/m3. After the flight the Falcon was inspected. So far no damages were observed including engines (after boroscopy) and windows. Further engine inspection is ongoing. Silver foils attached to under-wing stations showed no visible impact from volcanic ash.

Volcanic ash cloud: Pilots warn against 'rash' decisions to allow flights

European airline pilots warn governments about engine failures caused by ash amid pressure to get flights moving again

Pilots warn against ‘rash’ decisions to allow flights through the volcanic ash cloud amid pressure to get flights started again. Photograph: Gonzalo Fuentes/Reuters

European airline pilots warned governments and safety regulators today against making "rash" decisions to allow planes to fly through volcanic ash clouds amid growing pressure from airlines across Europe to create "safe flying corridors" to get flights moving again.

The pilots' intervention came as air traffic controllers dashed hopes that flights would resume from London Heathrow, Gatwick and Stansted this evening by announcing that most UK airspace would remain closed until 1am tomorrow. Airlines said the restrictions, which meant only a few flights took off from airports in Scotland and northern England, were an over-reaction.

BA announced tonight it was cancelling all flights until midday tomorrow.

The UK's air safety watchdog, the Civil Aviation Authority, is holding meetings with national air traffic controllers, airline executives and Lord Adonis, the transport secretary, to discuss flying through zones with small amounts of ash. But the European Cockpit Association, told the Guardian today that any attempts to establish "safe flying corridors" through airspace where ash was present should not be rushed.

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