Iceland volcano eruption risk level raised for aviation
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'all flying was stopped even private flying' err no it wasn't. I think you'll find there was quite a bit of GA around enjoying using bits of airspace in the UK that are normally not the easiest to access.
Tabs please !
I remember it well as I had to drive home from a trip. That was fun !
The relevant point is that it is not easy to see volcanic ash in the dark. The sensible answer would appear to sit somewhere between what happened last time and doing nothing.
The relevant point is that it is not easy to see volcanic ash in the dark. The sensible answer would appear to sit somewhere between what happened last time and doing nothing.
Avoid imitations
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The relevant point is that it is not easy to see volcanic ash in the dark. The sensible answer would appear to sit somewhere between what happened last time and doing nothing.
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I find it troubling how many supposedly educated, professional pilots still can't grasp that the reason for such a severe clamp down last time was not just because modern aircraft are designed to tighter limits than old, the technology changing as much as its susceptibility tot he ash, but more critically that the highly idiosyncratic circumstances of the eruption made the ash particularly hard to observe and simultaneously particularly threatening to engines. Comparisons to other events only serve to demonstrate those individuals' lack of comprehension of the technical elements of the event. Equally troubling is their blind dismissal of the tests carried out by several military aircraft which were subsequently found to have significant engine deposits and damage.
There's a HUGE difference between flying yer wee Cessna and operating a civil jet transport carrying fare paying passengers when there's a chance of running into volcanic ash.
My off the cuff judgement? If it's going to be on track, don't go.
My off the cuff judgement? If it's going to be on track, don't go.
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It was a complete mess up scientists as well hence why RyanAir reacted the way they did and did their own thing.
There has to be confidence in the science and frankly there was none.
as stated in the history of aviation no one has been killed flying into volcanic ash while many have been killed by bird strikes
There has to be confidence in the science and frankly there was none.
as stated in the history of aviation no one has been killed flying into volcanic ash while many have been killed by bird strikes
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no one has been killed flying into volcanic ash
However, your "history of aviation" doesn't have enough data to tell you what damage you can do to rather expensive engines ! Nor does it tell you the extent to which ash/dust can contaminate other areas through its ingress.
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It was a complete mess up scientists as well hence why RyanAir reacted the way they did and did their own thing.
There has to be confidence in the science and frankly there was none.
There has to be confidence in the science and frankly there was none.
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In 2010 the dispersion models actually worked very well. The concentration measurements that were taken verified the model results. The main problem at the time was that engine and airframe manufactures and ICAO had not developed standards relating specific particle concentrations to likely damage (or not), so the initial reaction was to prohibit flying where there was any non-zero predicted level - hence the large 'prohibited areas'. Hopefully there will have been some research since 2010 to enable more considered decisions to be made if required in 2014?
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I think the permitted level was something equivalent to a thimble full of ash in a volume equivalent to a 4 bedroom house 
and yes a lot more research needed to be done rather than picking figures out of the sky.
There are two aspects
Firstly the density of ash likely to stop an aircraft flying and endangering lives
The density over a prolonged period of time which will diminish engine life and the financial implications
Pace
and yes a lot more research needed to be done rather than picking figures out of the sky.There are two aspects
Firstly the density of ash likely to stop an aircraft flying and endangering lives
The density over a prolonged period of time which will diminish engine life and the financial implications
Pace
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Pace when you think how much air gets sucked into a jet engine every second and then look out how big the turbine blades are and how little of the contaminate is required to severely reduce there efficiency. Never mind the fact that minute quantities are required to block the cooling holes that run through them which if block means the blades over heat and burn up.
Actually its rather a lot.
I am very happy that the choice about flying has been given to professional engineers and out of the hands of airlines and pilots.
As this thread has showed pilots are pretty clueless about the risks involved. And the goat blowers in commercial have even less than the pilots.
Actually its rather a lot.
I am very happy that the choice about flying has been given to professional engineers and out of the hands of airlines and pilots.
As this thread has showed pilots are pretty clueless about the risks involved. And the goat blowers in commercial have even less than the pilots.
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Part of the problem at the time was the weather. From memory, there was a stationary high pressure system sitting over the NE Atlantic, and stuff was going round and round, rather than the air mass clearing to the east. I remember it well as I was working with my brother building a shed in his back garden. Putting the roof on I got slightly sunburned. In the UK in April!
@Pace
Possibly the ratio you were referring to was the May 2010 CAA revised limit of 4 mg per cubic metre of air, which equates to aprox 1g of ash per 250 cubic metres, (roughly the equivalent of your 4 bedroomed house example).
To help give this apparently insignificant figure better context, consider that a modern aircraft engine (with 118" fan diameter) has an intake fan area of about 7 m^2. When travelling at 250kts (aprox 125 m/s) this will ingest AT LEAST 875 cubic metres of air per second by virtue of mere 'ram air' effects, without any consideration for the significantly greater volume actually drawn in due to induction when producing thrust.
This is equivalent to ingesting around 4 grammes of ash as a minimum, EACH SECOND, or a WHOLE KILO of the stuff every 4 minutes. The reality is the figure would be considerably more for the reasons given above.
Given the significantly lower melting point of the clogging constituents of the ash than the turbine temperatures, I would certainly not wish to be the subject of live experiments with such quantities of ash in any engine that was keeping my backside from hitting the ground!
I think the permitted level was something equivalent to a thimble full of ash in a volume equivalent to a 4 bedroom house
To help give this apparently insignificant figure better context, consider that a modern aircraft engine (with 118" fan diameter) has an intake fan area of about 7 m^2. When travelling at 250kts (aprox 125 m/s) this will ingest AT LEAST 875 cubic metres of air per second by virtue of mere 'ram air' effects, without any consideration for the significantly greater volume actually drawn in due to induction when producing thrust.
This is equivalent to ingesting around 4 grammes of ash as a minimum, EACH SECOND, or a WHOLE KILO of the stuff every 4 minutes. The reality is the figure would be considerably more for the reasons given above.
Given the significantly lower melting point of the clogging constituents of the ash than the turbine temperatures, I would certainly not wish to be the subject of live experiments with such quantities of ash in any engine that was keeping my backside from hitting the ground!
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I am no expert, but the quakes are getting stronger, more frequent, shallower and closer to BungaBunga. According to the table we have had 4 over 3.0 since midnight for the first time this week.
Don't know if we can draw any significant conclusions or guesses from that, I will leave that to the seismologists.
Don't know if we can draw any significant conclusions or guesses from that, I will leave that to the seismologists.
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This report from the NASA DC-8 should also be relevant...
http://www.alpa.org/portals/alpa/vol...8ashdamage.pdf
I don't think anybody would want to fly with engines like that for too long
Lurking...
http://www.alpa.org/portals/alpa/vol...8ashdamage.pdf
I don't think anybody would want to fly with engines like that for too long
Lurking...
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Visit Nicarnica for updates & science:
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I am no expert, but the quakes are getting stronger, more frequent, shallower and closer to BungaBunga. According to the table we have had 4 over 3.0 since midnight for the first time this week.
Also it has not blown since 1910? So fingers crossed it goes back to sleep again
There are two fundamental problems with flying in volcanic ash:
a) We don't have a good method of determining where it is and at what concentration, and
b) We don't have a good understanding of at what concentration it becomes hazardous to aircraft.
Bird strikes can be (and have been) a problem - so there are standards and regulations. Manufactures need to demonstrate that their aircraft/engines can deal with a defined bird strike threat before they can be certified.
No one has ever done a test on a high bypass jet engine to determine at what concentration ash becomes a problem. We know the ~1gram/cubic meter that the KLM 747 experienced was a big problem. But what about 1 milligram/meter, or 1 microgram/meter? And how sensitive are different engines - would a concentration that was OK for a 1970s JT9D be OK for 21st century GEnx (or visa-versa)?
No one knows, and no one is willing to fund the necessary investigations and developments (at least so far). So for the time being, the only viable answer is complete avoidance.
a) We don't have a good method of determining where it is and at what concentration, and
b) We don't have a good understanding of at what concentration it becomes hazardous to aircraft.
Bird strikes can be (and have been) a problem - so there are standards and regulations. Manufactures need to demonstrate that their aircraft/engines can deal with a defined bird strike threat before they can be certified.
No one has ever done a test on a high bypass jet engine to determine at what concentration ash becomes a problem. We know the ~1gram/cubic meter that the KLM 747 experienced was a big problem. But what about 1 milligram/meter, or 1 microgram/meter? And how sensitive are different engines - would a concentration that was OK for a 1970s JT9D be OK for 21st century GEnx (or visa-versa)?
No one knows, and no one is willing to fund the necessary investigations and developments (at least so far). So for the time being, the only viable answer is complete avoidance.