Already posted and the aircraft was in a 'visible' (in the sense it blocked out star light) ash cloud, although the cloud was not avoided due to it being at night.

GarageYears

I read this report before but it is not a scientific study. All it basically says is that the aircraft was flying at NIGHT. That in itself is odd for a scientific flight? Why do the flight at night when the crew cannot see what they are flying into?

The only indication was the ash sensing equiptment on the aircraft which gave an ash indication.

The aircraft was checked on landing but with NO indications of an ash encounter on the initial inspections.

So much so that they continued for another 65 hrs of flight before the engines were stripped and damage discovered.

There is nothing to say that the ash encounter was the one they suspected. It may have occurred at a later time or an earlier time in a dense ash encounter.

This was a research aircraft which goes into these areas on purpose!
There are obvious cautions to take flying anywhere near a serious volcano.

One dont do it at night, make the areas no go at night.
Two I would imagine fly at very low engine settings in those zones.

There have never been any fatalities caused by ash encounters which is more than can be said for encounters with other weather phenomina or natural phenomina.

We dont ground aircraft in the bird migration seasons yet many aircraft have been downed by birds with fatalities caused by bird ingestion.

Thunderstorms, hail storms, severe turbulence etc have all downed aircraft with resultant fatalities but NOT ASH.

There are two types of threat in dispersed ash a threat to life which has not occurred yet in even dense ash encounters and a threat to the aircraft owners pockets.

The threat to the owners pockets is their choice? and not ours to judge over.

I see that Heathrow alone lost £29 million in the few days the airport closed. Who knows what the airlines lost but it was massive.

Yes have guidlines on how to operate near ash areas that is sensible but ground the whole of northern Europe???

As another poster said "life is a risk" otherwise we might as well stay in bed lock the doors and die of inactivity.

Pace

Distortions, distortions....
 

Pace, I suggest you re-read the report.

The flight was a positioning flight to allow the aircraft to conduct SOLVE missions (ozone loss and validation) within the Artic zone north of Sweden. So nothing odd there - just like my red eye to London or Amsterdam it is difficult to fly to Europe from the USA without hitting night at some point.

The fact they were running the instrumentation was standard practice.

The flight path of for the flight had been conservatively adjusted to put the track 200 miles North of the predicted ash cloud.

Immediately on landing the engine oil, oil filters and heat exchanger filters were removed and saved for analysis. Visual inspection did NOT reveal and damage, and since borescope inspection equipment was NOT available at the deployment airfield, and there was no apparent change in engine performance, the research flights continued.

There were seven SOLVE research flights and the report notes that ash was detected as traces during these, but at MUCH MORE DIFFUSE levels than in the first encounter - remember this is an instrumented aircraft, so they RECORD all this... there is no question where or not they flew through "a later dense ash encounter" - that is fantasy on your part.

As for your assessment that this is not a scientific study - well I leave that up to the reader to decide. I have yet to see any reports from any of the sampling flights over Europe that decided everything was suddenly perfectly safe.

My point - well, it seemed there was a lot of conjecture on the evidence that ash damages things or not. Here's evidence it does. The report includes measurements taken during the encounter of the sulfur dioxide concentration in parts per trillion by volume amongst other data, and it is clear when the encounter started and ended. The report also includes clear pictures of the disassembled engine parts.

My intent was to educate, not advocate - I'm not saying don't fly, neither am I suggesting fly.

Personally I have no intent of getting on an aircraft when I am aware there is a big cloud of ash floating in and around my flight path. My choice. Since most of my flights are for business and can be adjusted, I don't feel inclined to exposes myself to undue risk. I realize others do not have that luxury.

If you could let me know the next time a large flock of Canada Geese are in my flight path, then I will choose not to get on that aircraft also... for me it's all about risk management.

Oh, and let's see if there is a spike in engine maintenance over the next 6 months. Time to look at GE, PW and RR stocks.

- GY

Can I just make a few comments as a Geologist who has worked on a few active volcanoes? Apologies if similar comments have already been posted.

First, in no way does the Icelandic eruption compare with Pinatubo in 1991 or Galunggung (the BA B747 ash encounter) in 1982. Pinatubo had a VEI (volcanic explosive index) of 6, and was a once-in-a-century eruption; Galunggung was probably a VEI 4 to 5. The Icelandic eruption was probably a VEI 2 to 3 event. The VEI scale is logrithmic, so the Icelandic eruption was probably hundreds of times less powerful than Pinatubo. The Icelandic eruption took place over a week or so, which increases the total ash emission somewhat, whereas Pinatubo had a major highly explosive climactic eruption lasting only a day or so, but even so, Pinatubo and Galanggung emitted vastly more ash, and to a much higher altitude (50000ft+).

In the context of historic explosive eruptions, the Icelandic volcano is totally insignificant (at least so far!) In terms of human disruption, of course it's different matter. However, due to the location of Iceland on top of a major "hot spot" plume, or rising column of magma from the earth's upper mantle, eruptions in this part of the world can emit large quantities of lava or ash over time, due to the persistence of the magma column feeding the volcano, such as happened with the Laki fissure eruptions in the late 1700's. Now if the present volcano turned into a similar sized long-lasting event, we could have problems not just with ash but with vast volumes of SO2 and fluorine gases emitted, which could seriously impact food production due to reduced sunlight and toxicity.

A problem of assessing ash concentrations is that we are dealing with a four-dimensional problem, ie the eruption intensity and explosiveness is continually changing through time, as well as having a spatial effect. Volcanoes are notoriously unpredictable and explosive events are often in pulses with quieter periods in between.

I'm surprised that more effort wasn't made to obtain advice from Alaskan operators and the local VAAC who have to deal with explosive volcanoes from time to time.

Something to look forward to
 

"Back in 1783 another volcano in Iceland caused thick fog across Europe and even spread as far as the US, for eight months"

Followed by:

"Iceland’s Katla Volcano New Seismic Activity 4/28/10: Eruption Imminent Today, Iceland’s Katla volcano had a significant earthquake. Although no eruption has happened yet, this would be the normal course of events prior to an eruption. No official news story available at this time, but the seismograph data is available for public viewing here:

Icelandic Meteorological Office - Volcanic Eruption - Seismicity - Weather forecasts - Weather observations - Avalanches - Hydrology - Climatology - Sea Ice

It is not known when Katla will erupt but it is commonly accepted, especially by the Icelandic population, that this is only the beginning of the saga that will be the eruption of this massive glacial volcano. Earthquakes in Katla’s vicinity are the only real warning we have about when the eruption is getting close, and as we see seismic activity in the region increase, it will only mean one thing, that an eruption is imminent.
If you have been watching the eruptions at Eyjafjallajokull, you may be aware that this volcano is, historically, a precursor to large scale Katla eruptions. The president of Iceland spoke with the BBC about a week ago, expressing his concerns about Katla. He believes that it is not if Katla blows, but when. The history with this volcano and Eyjafjallajokull indicate that Katla could erupt anytime between now and a year or two from now.

GarageYears

If there is a spike in engine maintenance then thats not our concern or business!

No one has questioned the fact that ash can damage engines. So can Birds, Hailstones, sand, ice.

As stated Ash has not killed anyone even in severe dense levels. That does not mean that at some time in the future it may happen but it has not yet.

I stand by my statement that this was not a scientific study of ash encounters so while the encounter MAY have been the one which caused the damage or was even Likely to have been the encounter which caused damage there is supposition and supposition is not scientific.

There is risk in anything and it is your choice whether you even step on an aircraft.

Do I personally think the authorities over reacted at huge expense to the aviation industry then my answer is a resounding yes and driven by the media.
There is nothing new there as we have had so many media driven scares in other fields of science which have cost a fortune and have ended up as nothing that it makes for scepticism especially as it effects our industry and our livelyhoods.

Pace

The NASA DC-8 incident
 

GarageYears,

The NASA DC-8 incident has been cited in this thread several times.

Allow me to quote from the official report, which can be downloaded here

Top of page 11:
So, this was a flight at night through an ash cloud that was so thick that it was able to obscure the stars. Conclusion: this ash cloud would have been easily distinguishable by daylight VMC.

The research instrument readings returned to normal as soon as the stars had reappeared. This would suggest to me that no visible ashes, also means that no significant ash concentrations are likely to be present or even measurable.

This incident further shows that even flying through an ash cloud so thick that it can obscure the stars did not cause anything catastrophic to happen to the flight. (apart from the bill afterwards)

So allow me to use to use this incident to reinforce my ideas that keeping a flight clear of any visible ash concentration will keep the flight safe.

Therefore closing the entire airspace at is was done was a terrible overreaction.

Best regards,
Sabenaboy

Congrats on your worthless gift of 20/20 hindsight.

Would you have betted the lives of tens of thousands of fare paying passengers, as well as the financial health of six dozen airlines on this wild assumption before you had any scientific info upon which to base your decision?

No.

And neither did the European Governments.

Acceptable concentrations of ash (according to Flight International) are 10exp-17g/cuM.

Think on that number. There is no way, no way at all that you'd see or smell a concentration one hundred million times that level. No way at all.

Get a sense of proportion please - ie one several millions of times sharper than the one you are using right now...

:ugh:

Here's what I said on april 18th in my post nr. 819:
So yes, I would have "betted" my own life and that of my fare paying passengers in the conditions mentioned op april 18th! Sometimes using common sense is more useful then NON-EXISTING scientific facts! May I remind you that there has NEVER been an ash encounter flight incident unless in VISIBLE ash clouds!

No hindsight! that's what I said from the beginning! :)

I'm not so good with figures anymore, but this post nr 2477 appears to be a good reply to your figures.

Allow me to be just as disrespectful to your ideas as you were to mine by using the same smiley: :ugh:

However, the NASA flight crew mistook the ash cloud for cirrus. As stated elsewhere, ash particles coated with moisture(ice) would look similar to cirrus. Ash embedded in cloud would also be a potential problem, so day VFR would seem to be OK.
What is the plan for when Katla blows?

Sorry but that made my day. We had a sense of proportion when it was suggested that millions of birds were slaughtered to protect us from bird flu!
The science
We bought £2 billion worth of Tamiflu as the science predicted 65000 deaths
(346 the actual number) with the recent mexican flu.

It is our LACK of proportion in this media Hype reactive society and our run by committee and quango everything ( No one ever built a statue of a committee) and where the airlines had to push for some sensibility and sense of proportion.

I repeat no one was ever killed in an aircraft by ash encounters even dense ash encounters.

I flew a business jet north to south uk hours before the airspace was closed, beautiful day, 100 mile vis at FL250, no cloud apart from broken cumulus way below.
When does flight international become the authority on what is acceptable ash or not?

Keep some proportion thats a good one :rolleyes:

Problem we have is none of us will agree and this thread will keep going round and round in circles so best to beg to differ.

Pace

No, visibility was never part of the equations, that's your interpretation of it.

You picked the £2billion figure out of the air; its bull!!!! as Tamiflu doesn't cost that much and Pandemic flu is an on-going threat and the UK has a agreement to re-process the stock of Tamiflu as they expire. Flu pandemic last several years, until the entire worlds population becuase immune from the particular strain, Have you suffered from Pig flue yet? no? then you probably will do in future, maybe in milder mutation or maybe in its more severe form which kill you. The first year of Spanish flu was mild, the second year killed tens of millions.

The UK has a contract that allowed the cancellation of the VACCINE, which they invoked, will it be necessary to keep this contract rolling. Just becuase the average idiot on the street thinks infection disease are inconsequential doesn't mean that they actually are.

"Pig flu was nothing, give me Ebola, I'm invincible.", after all, flu is exactly like the science of aircraft safety.

Peter We

Have a read! There are plenty of other sources if you google them and dont like this one and sorry my mistake £1 billion :ugh:

The 'false' pandemic: Drug firms cashed in on scare over swine flu, claims Euro health chief | Mail Online

Just an extract

Pace

While the various handbag fights go on, I should perhaps explain that the purpose of my post #2485 was to gently nudge whomever that if we do NOT get our ducks in a row over this question, then when Katla blows, given the same classic North Atlantic pressure patterns being extant, the events of recent times will be just a walk in the park.

But who do we nudge?
 

BOAC, do you think Willie Walsh may be the right one to nudge? Or do the nudging? Certainly the Icelandic scientists seem to be concerned about Katia as there have been portents of seismic events in the last few days. Who is making plans to measure and plot ash clouds so that European aviation can avoid concentrations? Anybody?

Amen to that!

BOAC

That will be the next one DUCK FLU :rolleyes:

Sorry couldnt resist
More serious note yes I agree that proper research needs to be done to get realistic levels on different ash types maybe even not just ash damage but other pollutants.
From that research new training procedures for pilots in identifying ash and handling the aircraft in ash polluted air.
Because the reality is none of us really know and even the new levels have been plucked out of the air.

Now off with my handbag ;)

Pace

If we'd had the foresight to ask folks in areas where volcanoes are common, we'd have found different rules to what was applied in europe. Or maybe everywhere else is just unsafe and we know best, based on our once in a couple of centuries experience of VA...

You bet them anyway, by closing the airspace. Even aside the risk to folks stuck for a month without medication etc., many many thousands of others were diverted to road transport. At 30 times the fatality risk ppm. [and that is just road travel - before we even get into looking at ferries or people crossing the Channel in RIBs].

Media estimates were 1M pax stranded from the UK alone. If only 10% of those were repatriated by road then you have, statistically, caused multiple fatalities. Unless you have the science to prove flight was >30 times more dangerous than normal.
That science apparently wasn't available - so a decision was taken without it, to subject hundreds of thousands of pax to a known substantially increased risk of accident, through less safe modes of transport, in favour of avoiding an
unknown level of increased risk in the air, from a problem that has never caused an aircraft crash.

Even if the ash made flight ten times more risky than normal, that was still the wrong decision.

The airlines should have been allowed to do their own tests and risk assessments for their financial health. That's their job.

Shutdown cost esitmates for the airlines alone are around 100 times the repair cost of the NASA aircraft damage quoted above, per day. Did we see 100+ aircraft go tech each day for major engine repairs after flight was allowed through the ash ? Nope. Wrong decision on that basis as well.

Had we let the airlines take the financial risk decision, any cost (fly or no fly) would have been down to them. Instead, the (wrong) decision was forced on them, and they (rightly) want compensation as a result - which will be from us, the taxpayers, not from those in charge who will probably get a pay rise because the job of regulating aviation is so much harder than they thought before...

Not any more. 2000 ug/cuM is the safety limit, below 200 is no risk, 200-2000 is (paraphrased) fly on your own risk assessment. Allegedly, those limits are based on science, and themselves have a safety margin of several times below what the mfrs. have found to be dangerous.

So the new and (your quoted) old safety limits are a factor of about 10E14 different.

Now, to me at least, those figures are way too far apart to have both been arrived at without, as you say, "wild assumption before you had any scientific info upon which to base your decision".

So, which do you think is the "wild assumption" number and which is the one with scientific evidence... ?

errrr...in the interests of accuracy...

The NASA report includes reference detection by on-board scientific instruments of 'volcanic ash' but only by inference - I read it to mean that they ACTUALLY detected sulphur dioxide, which is also normally present in VA clouds but does NOT give any idication of ash density.

The chosen route for the flight was specifically intended to run to the north of a KNOWN ash cloud. The location information (from London VAAC??) was incorrect and the cloud was further north than thought. The reason for the error was partly due to the satellite imagery showing 'ice' clouds (ie. cirrus) rather than ash because ash particles had acted as nuclei for ice formation - so the satellite really was looking at a form of cirrus. It seems that once an ash cloud is 'old' and / or reaches a certain height, ash particles WILL get ice-coated and therefore difficult to positively identify.

Accurate detection of ash particle densities and drift rates of VA clouds therefore still seems to be a problem in the absence of research aircraft flying through them or very near to them. Covering that sort of area is probably infeasible. Hence my suggestions that there should be a far greater focus on post-flight inspections of ALL aircraft in affected regions to give a backstop check on where the ash is and where it's going as well as confirming the safe condition of the aircraft itself.