Who's right in the great volcanic ash safety debate?

On the third full day of havoc resulting from clouds of volcanic ash from a Chilean eruption being blown into Australian and New Zealand airspace it remains Qantas versus everyone else (even the RAAF) when it comes to its insistence on grounding any flights.

The argument that Qantas is playing the safety card at the expense of tens of thousands of stranded passengers is gaining media momentum. But even if this is the case, isn’t Qantas doing the right thing?

Given its dominant share of the traffic the stance taken by Qantas and its Jetstar subsidiary is causing some anxiety for anyone following the cautious commentary from the Volcanic Ash Advisory Centre in Darwin, which is that the ash clouds, density unknown, may close in on Perth, Tasmania and New Zealand again, as well as return to Melbourne, currently clear, or Adelaide, hopefully clearing.

With newcasts full of images of new waves of boat people swarming ashore off the car ferries from Devonport it is the most excitement Port Melbourne has seen since the end of glory days of the great ocean liners and the Adelaide Steamship Companies services to Sydney and Fremantle nearly 50 years ago.

The truth is Qantas and Virgin Australia and everyone else is obeying the only defined safety rule in relation to volcanic ash concentrations, which is not to fly through them.

They don’t need any encouragement to obey that simple prohibition. The expert testimony on volcanic ash encounters is unanimously negative. At low densities volcanic ash corrodes and destroys jet engines over time from very fine particle contamination, and at high densities causes rapid catastrophic engine failures, usually to all of the engines at the same time, putting the jet in severe peril.

The Qantas answer to this is not to fly under or near the “shoals” of particles. The Virgin Australia and everyone else answer is to see and avoid, flying detours around the concentrations and under them, never through them.

This is why on Sunday night for example, no one, not even Virgin Australia, persisted with night flights into or out of Melbourne airspace. Because no-one could see with prompt certainty where any possible concentration of ash particles might have been.

The volcanic ash advisory centre had told the airlines that the cloud, density unknown, was in the vicinity. And the particles are invisible to aircraft radar. So nobody flew.

This is the crux of the operational problem, in lay language: the volcanic advisory centres of which the Australian arm is a crucial part of a global network, track volcanic plumes on a macro scale. It is like determining where rain bearing clouds are likely to be on a broad scale without being able to define where the thunderstorms or heavy showers are going to be.

They do not, over trans oceanic distances, track ash plumes on a rapidly updated micro scale with the precision that the airlines need in order to locate and avoid potentially dangerous densities of volcanic particles while doing around 800-900km/h.

Last night everyone flew through Melbourne airspace because they knew with 100% certainty thanks to the Bureau of Meteorology and the volcanic ash advisory service that the plume had moved on. Unfortunately over Adelaide.

Today it is obvious from the live interviews streaming from airport terminals that Virgin Australia is cancelling or delaying flights because of the need to extend flight times to avoid the no-go zones determined by the ash advisory intelligence and BoM observations.

It is also obvious from the RAAF VIP operations decision yesterday to fly one of its Boeing 737s from Tasmania to Canberra so that the state’s federal politicians could make it to opening of the new session of parliament that the safety risk was zero.

But is Virgin Australia wrong? Is Qantas wrong? Both are actually right, it’s just that Virgin Australia has to work harder to stay right, while all Qantas has to do is stay on the ground.