Last Updated May 6, 2010 6:39 AM EDT
I wrote earlier that, bluntly, "I support the regulators." After talking to Willie, I've changed my mind.
My original basis for supporting the regulators is that this was a unique event with an unknown outcome and it's better to be safe than sorry. Now that I know more, it seems clear that the European regulators simply overreacted.
All airlines rely on someone for their weather information. British Airways works with a company called WSI, which kept BA updated throughout. What did they find? The model that the London Volcanic Ash Advisory Center (VAAC) used was incredibly conservative. WSI actually never predicted an ash problem over London. But when the UK's NATS air traffic control decided to shut down the airspace, those at Eurocontrol on the continent followed quickly and just shut it down as well.
The next six days were full of airlines arguing that it was safe based on their weather models and actual flight testing while the regulators refused to budge. Interestingly, Willie mentioned that when the airspace over Scotland briefly opened, WSI's models actually showed that there was a possibility of ash in the area, more than they saw in London at any time.
Someone asked Willie if other systems were seeing the same thing as the WSI model and he said yes. The London VAAC was the most conservative by far and it wasn't entirely accurate. Moreover, Willie says that NATS has no authority to actually shut down the airspace like that. It's up to the airlines to decide if it's safe to fly or not, just as it is when there are thunderstorms in an area. The airlines are well-equipped to make these decisions.
I brought up the issue of the military aircraft that were found with ash damage. Wasn't that a problem? Willie emphatically responded that it was a completely different issue. That isn't a safety issue but rather an economic one. The safety issue is whether or not the engines quit turning in flight, but there wasn't enough ash for that to happen. The economic issue is whether ash builds up in the engines and lowers their lifespan.
With the amount of ash in the air, that may have happened on a very limited basis over a long period of time, but they would have caught any problems with their regular inspections. If any ash starting building up, they would have caught it on the ground. So at that point, they could decide if it's worth running the flights and paying for the reduced lifespan or grounding the planes. Again, it wasn't a safety issue.
As you can see, he made some very compelling points; compelling enough for me to change my mind.