ANOTHER Icelandic Volcano

[CaptainChewbacca]

Link

VOLCANIC ash drifting southwards from Iceland's Grimsvotn volcano was due to reach the UK's main airport, London Heathrow, at about 1:00pm (10pm AEST), European aviation agency Eurocontrol said today.
The agency said in a Twitter message that a low concentration of ash was expected above the airport, and it advised passengers to check on the status of their flights with their airline.

Thousands of passengers attempting to travel to Scotland have already seen there flights canceled, prompting fears of a repeat of last April's transport chaos.

The threat of the ash prompted US President Barack Obama, who is on a six-day European tour, to cut short his visit to Ireland and fly to Britain ahead of schedule.

This could be another Eyjafjallajokull, so its worth keeping an eye on it.

[Hawkwings]

Apparently they've raised the limit on the amount of ash that aircraft are allowed to fly in, since the previous regulation was seen to be too tight. CNN

And I'm flying to the US out of Heathrow in a week and a half. I really hope it doesn't start getting more intense.

[El Moose Monstero]

Apparently they've raised the limit on the amount of ash that aircraft are allowed to fly in, since the previous regulation was seen to be too tight. CNN

And I'm flying to the US out of Heathrow in a week and a half. I really hope it doesn't start getting more intense.

They aren't anticipating it to get to the same severity as Eyja, I don't think. Grimsvotn is a crater lake volcano, so rather than there being a series of massive explosions as meltwater drained onto the lava, as was the case at Eyja, the lava will have to go through the standing water. At least until the ice raft lifts and it drains out, I suppose, but I don't know anything about that. Clive Oppenheimer at Cambridge has also pointed out that Grimsvotn tends towards a lower silica lava, which has a lower viscosity and so erupts more fluidly, allowing gases to escape more easily. You need high fragmentation energy in order to produce fine ash, and if gases can escape easily, that isn't going to happen to the same extent as we saw with Eyja last year. The sustained disruption from fine ash remaining aloft for several days over large areas of northern and central Europe probably isn't going to occur as a result.

[Broomstick]

Yes, I thought of Eyjafjallajokull, too - isn't this one affecting flights in the north of the UK?

I'm pleased someone reviewed how ash clouds are handled in Europe. Obviously, we can't have airplanes flying through significant amounts of the stuff but a more nuanced approach than "WHAA! SHUT DOWN ALL AIRSPACE" is probably a good thing.

[wautd]

Are propellor planes more resistant against this ash or doesn't it really matter? I would assume they are, but they were downed the last time as well and I don't know if it was due to overreaction or not.

[Zaune]

Yes, I thought of Eyjafjallajokull, too - isn't this one affecting flights in the north of the UK?

I'm pleased someone reviewed how ash clouds are handled in Europe. Obviously, we can't have airplanes flying through significant amounts of the stuff but a more nuanced approach than "WHAA! SHUT DOWN ALL AIRSPACE" is probably a good thing.

As far as I'm aware, last year's eruption was the first opportunity in years to conduct any tests for what concentrations of volcanic ash a jet engine can withstand, so the desire to err on the side of caution was understandable.

[Colonel Olrik]

Are propellor planes more resistant against this ash or doesn't it really matter? I would assume they are, but they were downed the last time as well and I don't know if it was due to overreaction or not.

Not exactly more resistant, but the comparatively high speed of the air and ash mix rammed into turbines that already have to work on a very hot environment is more likely to damage or even melt them than a propellor. Concerning the combustion chamber and nozzle etc there's no problem, the airplane might even have increased thrust..

I'd also be concerned with external sensors like the Pitot tubes, there are redundancies but a breakdown of those systems is unwelcome. Again, higher velocities compound the problem. Of course, if the ashes are more concentrated at lower altitudes than at higher ones the propellor plane might be the first to go Fubar.

[Broomstick]

The exact vulnerabilities of various types of aircraft differ, but volcanic ash is bad for all of them.

The problem of jets+ash was publicized last year.

With prop planes, there is the problem of air filters for the engines clogging, grit getting into moving engine parts and causing traumatic wear, and propeller erosion.

Moving parts on all aircraft are susceptible to ash contamination and wear. Keep in mind, volcanic ash is more like ground glass than regular dirt/dust.

Pitot tubes are a vulnerability for all aircraft that use them, which is pretty much all of them.

In addition, all aircraft windows are susceptible to "fogging" from volcanic ash, which looks pretty much as it sounds though the fade from clear to translucent to opaque is due to abrasion from ash rather than condensation.

[Jon]

Ryanair flew a 737 through the cloud at 40kft yesterday in an effort to 'prove' that there is no danger to aircraft. Hopefully this time the cloud will not be as disruptive as last year- if Iceland's volcanoes are becoming particularly active now we could be facing eruptions like this every other year for a while?

[CaptainChewbacca]

Ryanair flew a 737 through the cloud at 40kft yesterday in an effort to 'prove' that there is no danger to aircraft. Hopefully this time the cloud will not be as disruptive as last year- if Iceland's volcanoes are becoming particularly active now we could be facing eruptions like this every other year for a while?

In the early 19th century, Eyjafjallajokul vented almost constantly for a 20-month period. It could happen again.