Ash cloud over Europe should ground flights

Volcanic ash from last week's Eyjafjallajökull eruption continues to spread over the European continent, grounding flights and wrecking havoc on the European transportation network. At the time of writing, the Europe-wide grounding was continuing into its third day, with the major airlines losing some $200 million each day.

Taxi and bus services have been taking advantage of their position, taking some passengers on unusually long drives. Actor John Cleese of Monty Python fame paid a cool $5,000 for a taxi from Oslo to Brussels, for one. The ash has also forced many heads of state, include President Obama and Chancellor Angela Merkel of Germany, to cancel their planned attendance of funeral services being held for Lech Kaczynski, the recently deceased president of Poland.

Volcanic ash is dangerous to air travel for two major reasons. The first and more obvious one is that it creates a serious lack of visibility for pilots. While all commercial pilots are trained in instrument-only, no-visual flight in order to penetrate clouds safely, ash can stick to an aircraft's windshield very stubbornly, preventing visual contact with a runway or landing surface upon final descent.

Secondly and more importantly, volcanic ash can clog up the cooling system in piston or jet turbine engines. Without any ventilation, the intense heat generated by aircraft engines can begin to melt the metal structures they are encased in, resulting in serious in-flight damage to an aircraft from which there may be no possibility of recovery.

European Union aviation officials have been conducting test flights in and around the volcanic ash cloud, which hovers at around 5,000 feet in altitude. Their test pilots have been able to successfully circumnavigate the ash cloud, causing the EU to begin considering an early lift of the Europe-wide ground stop. Such a lift would be a mistake.

Test pilots operating successfully in an environment largely free of air traffic is one thing. Once additional commercial air traffic is introduced, a serious problem of control is generated. Managing Europe's busiest airspace in normal conditions is challenging enough. If normal routes have to be altered dramatically to take ash avoidance into account, controlling that airspace will only get more difficult, increasing the chance of accidents.

While the problems of disrupted air service and lost revenue are serious, the European Union must not allow services to begin until conditions are safer. Europe has already seen one aviation disaster this month, the continent doesn't need to bear witness to any more. In aviation, safety is always to be considered the absolute priority. Everything else takes a back seat.

In