Saturday, April 17, 2010

Iceland: Not Just Ice

I wasn't going to say anything about the volcanic activity in Iceland shutting down aviation across northern Europe, because I didn't think I'd have anything to add to the news coverage. But then CTV had a piece on it, including an interview with a former airline pilot in which they asked him why volcanic ash was such a threat to airplanes. His answer was that it forms very large clouds that don't show up on radar. That's true, but he never got to the nitty gritty of why, the literal nitty gritty, or at least gritty. Volcanic ash does not vanish to powdery nothing on your fingertips like wood ash: it consists of very hard, sharp particles of well-tempered glass. It flames out jet engines as its volume disrupts the airflow, damages the first stage from the inside by etching and abrading the perfectly machined moving parts, and then the glass can melt again inside the combustion stage of the engine and then re-congeal. Where it doesn't melt, it can mix with atmospheric moisture into a concrete-like slurry. The ash cloud also opacifies windscreens and inundates all moving parts, effectively sandblasting them.

Then the reporter set him up perfectly by asking, "Are you saying at an enormous 747 with four big engines could fly into ash and have all four engines snuff out?" By naming that specific type I suspect that the reporter had done some research and wanted the reveal of this flight or this one to be made by an actual airline pilot.

But instead of saying, "It has happened," the pilot said "it would never happen in practice," and went on to describe the satellite imagery and communications that steer aircraft free of ash clouds. I'm sure he knew about the BA flight, and was acting on the side of not panicking people and giving modern information. Technically the ash only shut down three engines on flight 9, as one of the engines had already been shut down as a precaution. That was in what saved them, because the engine that had not been running during the ash encounter was able to restart.

Oh and here's a brilliant piece of ignorance from a commenter on a CNN article. (Sorry I don't have the link, someone forwarded the text to me).

The ash cloud has stopped fights because of the danger of it stopping the aircraft engines? Another blatant lie. How were those aerial photos and videos taken? Those aircraft were far closer to the ash plume than commercial craft would fly. Why didn't their engines stop?

Perhaps the airlines sold this little falsehood because the real problem is that the ash would cause extra wear in some engines and they don;t want the expense of more maintenance. As always, the news media eagerly repeats any "official" story without thinking, "Can this be true?" Follow along now sheeple, nothing to see here. You there! Stop that thinking right now!

That person probably thinks airplanes fly just fine underwater, because he's seen lots of aerial shots of oceans and lakes. Just to be clear, that's from a member of the public in an online comments section, not a paid member of the media. But hey, at least he's not believing everything he's told.

Here's a geekmade tool showing the skies over Britain clearing of aircraft after the warning came out, the largest airspace closure since September 2001. There's an upside, though, according to this infographic on CO2 emissions.

I've never had a volcanic ash encounter, nor had to cancel a flight for ash. I have seen volcanoes and wow. The Earth itself can wreak havoc. Maybe there will be fish to eat in the future after all. Fish that breathe fire!


arcady said...

My favorite phrase from the news reports about this is "cloud of basalt". Basalt is not one of those things that you typically think of as coming in clouds.

zb said...

Greetings from a city that has its airport closed since 8pm last night. I feel bad for everyone who is stuck now, but if you manage to go back one step and try to look at it from a wider angle, some things come to mind that I like:

- Isn't it incredible how much we take the air travel system for granted and don't seem to appreciate how much complexity is involved in terms of technology, logistics and people to keep it alive? The ignorance proven by the quotes in your post seems to prove this even more.

- Isn't it great how many people are still able to reach their destination at least within central Europe and at least within, say, 200% or 250% of their original scheduled time of travel because of a good train network and the diversity of road travel? I really have no intentions to bash on the airlines, it's just that I don't like to depend on just one way of doing things. It's an idea called freedom.

- Again, I don't want to bash air travel, but if I lived underneath the departure path of FRA, AMS, LHR or any other huge airport, I would party so hard that my neighbors would have just another sleepless night.

I think an event of this scale does have the power to make us ask some good questions and because the event was triggered by nature and not by war, terror or weird politics, it may even be a bit funny -- even though a lot of people are put in an uncomfortable situation.

townmouse said...

I have to admit, I'm enjoying this (even though my sister has had to cancel a visit to my parents). I almost wish I still lived and worked under the Heathrow flight path so I could really appreciate it... Like zb, I think we've all started to take flights far too much for granted and if we have to live for a week or so without Kenyan green beans, or weekend trips to our second homes in Tuscany, it will do us all a world of good. And if we have to rearrange our lives a little so that flying is reserved for when it's really needed, then so much the better.

Aviatrix said...

Good points, you guys. I'm glad I did the post.

Sarah said...

So, is it a general aviation party in Northern Europe? Are the Cessnas and Pipers flocking Heathrow and Amsterdam?

Surely the service ceiling of any piston aircraft is well below the ash cloud?

A Squared said...

I've never had a volcanic ash encounter, nor had to cancel a flight for ash.

Once the novelty wears off it's a real freaking nuisance. (novelty wore off for me about 20 years ago) I could quite happily live with no more volcanic eruptions.

A Squared said...

Surely the service ceiling of any piston aircraft is well below the ash cloud? Which direction do you suppose ash goes relative to the local gravitational vector, up or down?

How much ash is in the air you're flying thru? How do you tell when you're IMC?

Cirrocumulus said...

Townmouse: here's some local colour from west of Heathrow.
It's been a very quiet cloudless blue-sky day, absolutely nothing up there except acrobatic red kites and about an hour before sunset, a single light aircraft at about 2500'. I don't know why it was allowed out when the others aren't.
Just now a golden afterglow is fading to indigo with one bright planet in the south-west. And not one moving light anywhere on that perfect dome.
The quiet picks at the edge of your awareness: you don't normally notice the whine and grumble of aircraft so when it stops you just have a vague feeling of something unusual.

It wasn't like this in 2001 because then only transatlantic traffic was affected. Now it's all stopped.

zb said...

Yeah, just came home from a walk during the hour of sunset and did a fair amount of biking today. The only aircraft in the skies above MUC/EDDM was a blimp today.

The sky looks fascinating with no contrails. It must be the best of all days for film crews considering how much trouble they go through when they have a pre-1920 (or so) story and can't do any filming outside because a 747 with a contrail just won't fit in the scenery of knights and castles.

Sarah said...

@A^2: Which direction do you suppose ash goes relative to the local gravitational vector, up or down?

How much ash is in the air you're flying thru? How do you tell when you're IMC?

How much ash invisibly falling (down, I'm pretty sure) from high altitude clouds do you think it would take to clog an piston engine intake filter?

Why would anyone concerned about volcanic ash choose to fly in IMC?

It's moot anyway - the large airports are just closed, as is much of the actual airspace.

A Squared said...


If you're not flying directly in an eruption plume, the concern is not sudden engine stoppage, but accelerated engine wear. Volcanic ash is about the worst imaginable substance to aspirate into your engine. It's hard as glass, and unlike most dust which is the result of erosion, and thus fairly rounded on a microscopic level, volcanic ash is very sharp.

Splendor said...

I guess I have the dubious honour of having been one of the first cancelled passengers as I chose the day of the eruption to travel home for 2 weeks. Never mind.

Three days in and the airlines generally are starting to get tired of these blanket airspace restrictions based on forecast ash area (it's not the airlines who aren't flying, it's the authorities who won't let them) and the last Euroontrol conference call was a bit agitated.
I think some companies are willing to trade extra wear for the possibility of getting at least a few flights going.


Sarah said...

Aha, looks like aluwings has answered my question. Yes!

Zurich T&Gs

Paul B said...

I was due to go to Sweden to give training this week, but that had to be cancelled due to the lack of flights.

I looked at alternatives, like trains, but with a travel time of around 2 days, that wouldn't work for me.

It has been strange to look up into the sky (and this last week, we've had lovely clear skies for a change) and NOT see the vapour trails.

Paul B said...

By the way, if you've not already seen it, here's a great site to watch the planes over europe...

Curt Sampson said...

Am I overly sensitive, or was that "perilous passage" article just a bit over the top? I myself find it hard to think of something gilding at a 15:1 ratio as "plunging," even if it is losing 2000 fpm.

What are they going to report next? The recent 747 flight where the pilot "shut off" the engines whilst still "miles away" from the airport, causing a "plunge" down to the runway, where it "impacted at at 180 mph"?