Ash Wednesday

The decision to reopen Europe’s airspace does not mean its closure was a mistake

From Times online April 22, 2010

[Translate the first following five passages into Chinese]

Let us be clear. The simplest way to demonstrate the exact risks to air travel posed by volcanic ash emitted by Eyjafjallajökull would have been to allow airliners to merrily fly in it until one or more of them fell abruptly from the sky. From the moment that aviation authorities opted not to pursue this course, the cry of “overreaction” was inevitable.

Clearly, the past seven days of clear skies have been extremely damaging for the airline business. As carriers began to resume their schedules yesterday, the International Air Transport Association estimated a cost to the industry of $1.7 billion. Add to that the business cost of employees stranded and meetings cancelled, along with the more human costs of ruined holidays, schooldays lost and families separated, and the urge to find somebody to blame becomes more than understandable. And yet, it is misguided.

“Six days into the crisis,” thundered Theresa Villiers, the Shadow Transport Secretary, yesterday, “we’re suddenly told that there are actually levels of ash which are compatible with safe flying.” She went on to question why the Government had not been aware of this before the crisis occurred. This is not a fair question. Much of the Government’s handling of this crisis has been suspect, most notably the Prime Minister’s farcical promises of fleets of buses and evacuations by the Royal Navy. But the risks posed by ash were never hypothetical. The cases of two Boeing 747s that suffered engine failure over ash from an Indonesian volcano in 1982 have been well reported.

Since the advent of radar and satellite imagery, however, this has not been a European problem. Worldwide, indeed, no event of this sort has ever approached the scale of Eyjafjallajökull. This meant that aircraft were not equipped to detect ash, most pilots had not flown in it, and most air traffic controllers had not navigated it. From the ground, indeed, it is close to invisible. Models to predict its movements are vague, and instruments to calculate its density are rare.

Much is now known about the ash cloud that was not known six days ago. Its composition is known to be basalt, rather than the more damaging andesite. Test flights have shown that aeroplanes can pass through less dense areas of cloud. These may have called existing guidelines into question, but those guidelines did exist. On the basis of what was known, any other course would have been foolhardy.

When scientific probabilities collide with the political need for certainties, the results are always clumsy. Lord Adonis, the Transport Secretary, displayed admirable candour when he told Jeremy Paxman, on Tuesday night: “I probably know as little about the technical side of this as you do, Jeremy”. In his words, though, was a worrying undertone of distancing — the suggestion that such decisions need not even be explained by politicians, because they rest in the hands of unaccountable experts.

That our politicians — and perhaps, our media — are often so visibly out of their depth on scientific matters is a failure in the responsibilities of scrutiny held by both. Today, even so, the correct response is to be glad that our skies are open again, and welcome home those who have been kept away. Most of all, though, we must remember that “health and safety gone mad!” is only an easy thing to cry when all are healthy and safe.