Volcanic ash: you can’t avoid if you can’t detect it

If you’re wondering what all the fuss is about with the “ashpocalypse” still shutting down most air travel in Europe, particularly in the light of several airlines trumpeting successful ‘test flights’ through the European skies, this is the only quote you really need to read:

Guy Gratton, head of Cranfield University’s facility for airborne atmospheric measurement, took a flight with fellow researchers to gather data.

Speaking as an aeronautical engineer, I would not want to be putting an airliner up there at the moment, said Gratton.

There is a lot of fairly nasty stuff there that we were running away from, knowing what we did. We have standard airline instruments on the aeroplane, we have got a storm scope and we have got a weather radar and they were looking straight through it.

Neither of those were seeing any of this stuff. It was only our specialist cloud physics instruments that were able to see the particles.

Jet engines do not react well with volcanic ash, but this would not be so much of a concern if commercial airliners could detect when they were flying into areas with dangerously high concentrations and divert around them, much as they do with storm systems. But the ash is too fine to be picked up on radar, meaning that normally equipped planes are effectively flying blind, reliant on external satellite and model data to steer a safe path. Do these data sources have the reliability, the resolution, and more importantly, the timeliness, to provide the pilots warning that they are flying into danger? A pilot’s first indication that something was wrong could well be when an engine shuts down.
Hopefully someone is seriously exploring solutions to this detection problem (can that specialised cloud physics instrumentation be deployed more widely, I wonder?), which is in the long term the only way to minimise disruption if Icelandic volcanism continues. In the meantime, it’s interesting that many people seem to be chafing more at the disruption brought on by a natural hazard with a clear and well-defined associated risk, than they do at restrictions in the name of protecting us from the much smaller chances of an undefined terrorist attack.