So was the flying ban the right thing to do?

[Kata]

Are you a banker by any chance ?

My job is about a million miles away from banking. Why do you ask? I can see no relevant connection between what you highlighted, and your comment.

[peterb]

The question is, what is the "plume". In most places, it is taken as being the visible column and trail of ash downwind. The European governments took it as being every possible bit of airspace that might have some ash in; therein lies the problem. It's good to see that common sense, led by the airlines, has prevailed.

I'm not sure I'd call it common sense, the kindest word I could use would be pragmatic - if I was unkind I'd say commercial self interest.

[TheAnimus]

Any type of analysis which requires a logical assessment of risk of ending life and contribution to having a full life is obviously only done by those evil bankers.

Good hearted people are too busy picking flowers and reading The Mirror to think about helping people.

(such as those who where waiting medical aid or organs say)

[Kata]

I'm not sure I'd call it common sense, the kindest word I could use would be pragmatic - if I was unkind I'd say commercial self interest.

Why is it not common sense? I would say that recognising there is no risk at all, due to the fact that airliners in Alaska and other areas operate fine in these conditions, not to mention test flight, is common sense.

You seem to be implying there is still a non-negligible level of risk associated with the tiny concentration of ash in the air. What evidence can you cite to support this assertion? The alleged damage to fighter jets is not relevant, due to the very different operating conditions of their engines, and their flight regimes.

[peterb]

No, I'm saying that the risk has not been quantified (although risk assessment is subjective anyway).

Any engine will suffer damage through slid objects - we normally call it wear, and the degree of acceptable damage or wear determines the maintenance regime for that object - which are (rightly) conservative in aerospace applications. However the engine mfrs couldn't quantify the additional wear caused by the extra volcanic debris in the atmosphere, simply because the data wasn't there.

There is an additional factor in the abrasiveness (and size) oif the polluant - flying through fine diamond dust may cause more damage than (say) sand - or the damage may be different. One might cause loss of compressor efficiency, or damage to the combustion chambers, which could cause loss of efficiency, while another may affect bearing surfaces and cause catatrophic failure (in an engineering sense)

I give those as examples of failure modes, I don't know what the abrisiveness of the debris is or how it might have affect a jet engine in specific instances.

While I agree that military jet aircraft have different (and more hostle) operating conditions, their servicing regimes refglect this, and the same criteria, the unknown effect of the contaminant is still relevant.

The common sense approach was to halt flying until an assessment could be made on data gathered. Once it had been, flying resumed.

It is easy to look back and say that it was an over-reaction, but then hindsght is usually 20/20.

[Terbinator]

I don't see how citing the airlines for proof is really transparent as they have a vested interest in getting off the ground as soon as possible.

[Kata]

However the engine mfrs couldn't quantify the additional wear caused by the extra volcanic debris in the atmosphere, simply because the data wasn't there.

But the data IS there; tens of thousands of flight in and out of Alaska during volcanic events, for a start, not to mention every other volcano in the world.

The common sense approach was to halt flying until an assessment could be made on data gathered. Once it had been, flying resumed.

It is easy to look back and say that it was an over-reaction, but then hindsght is usually 20/20.

I agree that halting it immediately was excuseable; what was not excuseable was the length of time that the authorities sat on their arses ignoring all the data and precedents.

[Kata]

I don't see how citing the airlines for proof is really transparent as they have a vested interest in getting off the ground as soon as possible.

Seriously, what part of "The airlines don't want their aircraft to crash" do you not get?

They have a greater interest in not crashing, and avoiding the enormous after-effects of a crash, than they do in running a few extra flights. And, even taking this into account, they are happy to fly. Who do you think knows more about the aircraft that the airlines operate; them, or the mostly useless bureaucrats at the CAA (and I judge them based on experience with them).

[Terbinator]

Seriously, what part of "The airlines don't want their aircraft to crash" do you not get?

They have a greater interest in not crashing, and avoiding the enormous after-effects of a crash, than they do in running a few extra flights. And, even taking this into account, they are happy to fly. Who do you think knows more about the aircraft that the airlines operate; them, or the mostly useless bureaucrats at the CAA (and I judge them based on experience with them).

I highly doubt the after-effects would cost more than the amount they're claiming to have lost while flights were banned.

[TheAnimus]

I highly doubt the after-effects would cost more than the amount they're claiming to have lost while flights were banned.

Seriously?

I die inside when I read posts like that, think about it, please just think.

They lost 100% of flights for 1.65% of a year.

In other words a 1.65% revenue drop assuming equal distribution annually.

How many people wouldn't fly for AT LEAST 1 year if a plane dropped out of the sky because of safety fears due to complete incompetence?

More than 1.65%, I would be very surprised if it was less than 30%.

[Chris P]

If it happens again let's organise a plane for all the customer's who feel closing the air space is an over reaction and sign their life away if something does happen.

I wonder how many of these customer actually get on it?

I think it was correct to close the Air Space, thankfully no planes dropped out of the sky, at the end of the day this is all that should matter. It's pretty easy for the people to make comments about the decision when it's not their decision to make, if they were in the " hot seats " then I think their decision would be a whole lot different.

[Kata]

I would, and did, fly with no doubts throughout the "ashpocalypse". The only way to make sure no planes ever drop out of the sky, Chris, is to keep them all on the ground. EVERYTHING else is risk management. Thunder is statistically a greater risk to aircraft than volcanic ash; do you refuse to fly when thunderstorms are forecast?

[peterb]

But the data IS there; tens of thousands of flight in and out of Alaska during volcanic events, for a start, not to mention every other volcano in the world.



I agree that halting it immediately was excuseable; what was not excuseable was the length of time that the authorities sat on their arses ignoring all the data and precedents.

Ignoring or analysing and assessing? After all, it isn't in any countries economic interest to keep aircraft grounded for longer than they have to.

I see two airports in Iceland have been closed today after the wind changed direction. http://www.telegraph.co.uk/travel/tr...irst-time.html

I gather one of the factors was that the eruption was under the glacier, so the hot lave instantly froze and shattered, so it may be that the debris was different from that normally encountered (but I don't know - you may) and as I said in an earlier post, according to the interview on R4 yesterday, the safety case for the engines is predicated on avoidance of concentrations of volcanic debris.

I acknowledge that the aerospace industry is very safety orientated, which is why I would say that the decision to open up the airspace was pragmatic.

[Terbinator]

Seriously?

I die inside when I read posts like that, think about it, please just think.

They lost 100% of flights for 1.65% of a year.

In other words a 1.65% revenue drop assuming equal distribution annually.

How many people wouldn't fly for AT LEAST 1 year if a plane dropped out of the sky because of safety fears due to complete incompetence?

More than 1.65%, I would be very surprised if it was less than 30%.

No I agree, but I don't think it would be produced to us as incompetence on the airlines half. I imagine we would be spun something along the lines of it was worse than could be predicted etc.

[Chris P]

Kata

Planes are tested against lightning, as far as I am aware they are not tested to fly through the conditions produced by this eruption? Looking at the images of the Finnish F18's engines damaged after flying in these conditions and ingesting volcanic dust, the decision was correct.

Had a plane crashed then everyone complaining would instantly be blaming NATS for not grounding the planes.

[Kata]

The danger in thunderstorms is turbulence more than lightning, and it does not alter the fact that thunderstorms are more dangerous than ash. Aircraft have crashed because of thunderstorms, none have ever crashed because of ash.

As I have said countless times, but people seem unable to comprehend, we DO know how aircraft engines handle dust due to experience in Alaska, the East, etc of operating around volcanoes.

F18s engines operate at greatly different internal conditions, and under different flight regimes. Far more relevant are how airline engines are afected; and, as shown by the test flights and experience elsewhere, they are fine. I have pointed this out at least once in this thread, as well...