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Ash clouds threaten air traffic

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Ash clouds threaten air traffic

Old 20th May 2010, 19:13
  #2941 (permalink)  
 
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If there is no problem than it won't be too difficult to persuade the manufacturers to loosen their guidelines then, will it?
Peter

The answer to that is Yes it would be difficult to make them move from what they have to anything which makes them more liable but unoffically NO!

Why should they? would you in their position? as prob they dont know either.

Pace
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Old 20th May 2010, 19:17
  #2942 (permalink)  
 
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The tech log entries I have seen refer to 'unknown contaminant on turbine blades' etc etc. After assorted checks, the CRS states 'within limits' or similar.
But this 'unknown contaminant' could be almost anything - pollution, quarrying near the airport to name but two - and could have nothing whatsoever to do with the unpronounceable volcano. I am also told that there is (was) no baseline sample from the volcano, and until that happens the contaminant cannot be linked with the volcano.
In other words, if all engines had been subject to the microscopic internal scrutiny that they are now, 'unknown contaminants' could well have been found before the volcano, and could have been irrelevant.
Aside from the full strength Eric Moody volcano encounter, the major problem is surely going to be erosion and performance degradation - and that won't be apparent until engines are prematurely removed in the next few months. Our Lords and Masters are most likely barking up the wrong tree (imagine my surprise).
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Old 20th May 2010, 21:29
  #2943 (permalink)  
 
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let's face it

if there had not been a total flight ban over Europe on that first w-end when the eruption had started in April we definitely would have seen some maybe even serious events on the civil side of aviation..

just want to remind everyone on what had happened to the Finnish F/A-18s..on that first w-end

That is a fact

What happens now, if I look through the new UK CAA procedures with TLZs etc etc , and we are talking of up to 4000 MG / m3, the folks from the engine manufacturers to whom I talked yesterday are just laughing..

Now, as an AOC holder you will have to "build a safety case"...

Just to say, they others also fly will not suffice..

And you as an operator will have to get the nod from the engine folks..

well, they will give you some maintenance and inspection requirements, maybe..( some of those could amount to nothing less, than having to perform a hot-section inspection every couple hundred hours on certain types..( which may make flying cost-wise unfeasible...it will destroy the bizplan of a lot of airlines..)

What I really want to know though, the engine manufacturers definitely will put a legal disclaimer on EVERY PAGE of their enhanced procedures, that in fact they DO NOT RECOMMEND flying in that cra...

So how do you build a safety analysis, if the most important link in the chain , the engine folks, will say, better dont do it..??!!

Dont get me wrong, I do understand that especially the UK is in trouble now, if that mountain continues on and on, depending on weather you in the UK will have high ash concentration days every week or every second week or so..

And I understand that keeping the planes up in the air beats reverting back to sheep farming and whiskey..( now that the EU even wants to "regulate" your hedge funds, and London could lose quite a bit of funky /junky biz)

and then on top your airspace gets dirtied up every 10 days..

I understand..

what I do not understand though is, up to now, we in aviation strived to have the best safety record and try to better it every decade or so..

If that new "let's all fly in the dirt now" should go fundamentally wrong, all the good work of the last decades to make commercial aviation one of the safest form of transportation in history, at least in North America and Europa,( am not talking about Africa, Russia etc etc) but all that could literally go up in smoke overnight...and you wont find any passengers no more even once that mountain will have stopped smoking..

And until now, for testflying you got paid....the traveling public though is paying for their seats in the back and at the end paying the salaries of all those wise-guy pilots here, who think it is a swell idea to suddenly cut back in safety..

think about it..

Last edited by falconer1; 20th May 2010 at 21:40.
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Old 20th May 2010, 22:15
  #2944 (permalink)  
 
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Falconer1

Remind me, how many F18s did the Finns lose that weekend? Were the crews able to eject before their jets smacked into the sea? Did they lose any SAR helicopters on the rescue mission? No?!

Might as well stick my head above the parapet!;
I don't believe there is a flight safety issue here. I believe the issues are financial and as such the airlines should be able to choose to fly subject to agreed boroscope inspections.

The media and people with a dangerous half-knowledge of aviation would have you believe that flight over the UK on Sunday 16th/Monday 17th May would have caused aeroplanes to fall out the sky. That in my opinion is boll**ks!
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Old 20th May 2010, 23:56
  #2945 (permalink)  
 
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The media and people with a dangerous half-knowledge of aviation would have you believe that flight over the UK on Sunday 16th/Monday 17th May would have caused aeroplanes to fall out the sky. That in my opinion is boll**ks!
I have another perspective

The "media" in the above statement is way too inclusive. I do agree however about the so called "half-knowledge" and it was exactly this point that resulted in the initial early May sense of caution excercised while the half-knoweldge was being converted to a better understanding of reasonable risk-tolerance actions.

The half knowledge still exists today among many, but fortunately those entrusted with the flight safety decisions have much more knowledge today. Tis true that the initial early actions were with an abundance of caution and in hindsight resolved themselves way too slowly. And many lessons were learned.

I get a better feel of where we are today by following what little print shows up in the mainstream of the truly international written media
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Old 21st May 2010, 06:27
  #2946 (permalink)  
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Pace,

I am here to talk about volcanic ash, not to engage in repartee, but it seemed there was an implicit query in your last contribution as to why I and others don't simply accept your point of view. It might thus be worthwhile to tell you, just this once.

You suggest that you and sabenaboy and «most of the ATPs [whom you] know» think there is no hazard associated with flying «as usual» in the ash clouds.

To perform any risk analysis of the situation, one must do the following: (a) assess the chances that this is right; (b) assess the deleterious consequences that will follow (the «damage»; here we may take it that there is none); (c) assess the chances that this is wrong; (d) assess the damage in this case. Then one multiplies (a) by (b), and (c) by (d), and adds the results. We may take it that multiplying (a) by (b) yields zero because (b) is zero. So your assessment of risk is equal to (c) times (d).

That is the way it's been done for 299 years, and it seems to work. But far from attempting to estimate (c) and (d) in any way, you have mostly just disparaged people who have attempted to do so here. I conclude you know nothing about risk analysis. (Let me assure you further that the risk analysis of rare events is a tricky, indeed specialist, subject, to which I don't have the space here to do justice.)

So the answer as to why I, and others, do not accept your point of view is that you haven't attempted to perform the required analysis, so there is nothing yet to accept. It's as simple as that.

BTW, I made a conditional statement «if A then B», and you highlighted «B» and took me to be asserting it. We used to have fun with people who did this in school as follows. We used to say «if your nephew is a monkey then YOU ARE A MONKEY'S UNCLE! It's TRUE! Go ask teacher.» The victim would go ask teacher, who would then agree, yes it's true. And explain. Victim would thereby learn something. It seems schools have changed since then. Pity.

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Old 21st May 2010, 07:11
  #2947 (permalink)  
 
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Right enough Loma, I should have said 'certain parts of the media'. Apologies for tarring everyone with the same brush.
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Old 21st May 2010, 08:45
  #2948 (permalink)  
 
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(Let me assure you further that the risk analysis of rare events is a tricky, indeed specialist, subject, to which I don't have the space here to do justice.)
PBL

What better risk analysis can you have than 50 years of records and millions of flights?

The undisputable facts are that NO ONE has been killed in the whole history of aviation by ASH.

You are trying to do a risk analysis on something which to date statistically has shown NOT to be a risk.

There were two incidents where aircraft entered dense ASH clouds at night.
I am not talking about flying into dense ash cloud but flying in VMC daylight through ash concentrations which are so low that they are invisible to the human eye.

You have to differentiate between a threat or risk to life on which statistics over 50+ years show there to be none and a financial risk where there is a vague possibility that flying in low levels of ash or indeed any pollution may reduce the engine life. That is an accountants job not a health and safety issue.

If you want to do a risk analysis then great but look at areas which do have a record of continuing threat to life which we accept such as bird migrations sea based airports, weather winds etc etc etc.

My concern as a pilot would be flying into something which would cause an immediate failure in flight and thus cause me a problem. I do not believe until someone shows me otherwise that low density ash is a threat to causing an inflight failure.

If the engineers start posting here that they are finding ash damage which could cause that failure then I will sit up and listen but it hasnt happened yet.

But this is going round and round in circles and it maybe better to agree to disagree.

Pace

Last edited by Pace; 21st May 2010 at 09:35.
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Old 21st May 2010, 09:31
  #2949 (permalink)  
 
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There were two incidents where aircraft entered dense ASH clouds at night.
...lets not go too far to under-state the risk.
There have been documented daytime 'incidents' involving damage to engines apparently caused by VA. Thankfully nothing involving any personal injury so far, most recently, the Finnish F-18 encounter - of which nothing much more has been reported. I don't recall reading what the visibility was at the time but I don't think it was at night. Presumably even military jet jockeys know not to fly through VA.

Also, lets not forget that this part of the discussion started with photos of a Cessna engine problem. This has already been quite thoroughly refuted by someone presenting themselves as a Cessna employee. Given the lack of any re-refutation in the original threads, this is now a Dead Letter. Why 'provenance' of a false rumour could be interesting defeats me. Maybe PBL should subscribe to the UK Daily Star for countless better examples that serve only to sell newspapers.
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Old 21st May 2010, 10:08
  #2950 (permalink)  
 
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...the Finnish F-18 encounter - of which nothing much more has been reported...
Well, I found this link to a flightglobal article:
PICTURES: Finnish F-18 engine checks reveal ‘no significant damage’

Isn't it ironic that I came across that link after reading PBL's blog?
I don't recall reading what the visibility was
True! I didn't find any information about the flight conditions of that F-18 mission. I'm interested to hear about it, but I would not be amazed if it wasn't by flying in clear blue sky that their engines were "not-significantly-damaged"!

Best regards,
Sabenaboy
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Old 21st May 2010, 10:14
  #2951 (permalink)  
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Originally Posted by brooksjg
Why 'provenance' of a false rumour could be interesting [to PBL] defeats me.
The "refutation" and "lack of re-refutation" have no more status than the original rumor. For hobbyists, this might be enough. For many professional purposes, it does not suffice.

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Old 21st May 2010, 10:56
  #2952 (permalink)  
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It looks from the synoptics as if there may be a drift towards the west of the UK by 25th.
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Old 21st May 2010, 13:10
  #2953 (permalink)  
 
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Earthquake action continues

Earthquake activity both at Eyjafjallajokull (many) and again two at Katla (the most recent occurring in the last 4 hours, while not very big at 0.4 on the Richter scale, was deep at 13.7km which is concerning).

Also just found out that the last time Eyjafjallajokull erupted it lasted for 14 months.... so this could be a long thread.

- GY
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Old 21st May 2010, 13:39
  #2954 (permalink)  
 
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What better risk analysis can you have than 50 years of records and millions of flights?

The undisputable facts are that NO ONE has been killed in the whole history of aviation by ASH.
What a very strange thing to come out with. You could use the same logic with Concord; it had a perfect safety record, until it didn't.

Maybe its becuase aircraft have always avoided flying through dust, certainly when they do, in certain concentrations its got very very expensive and dangerous. And VA is not the same from all eruptions, some, like this, are far more damaging.
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Old 21st May 2010, 15:22
  #2955 (permalink)  
 
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Yet more earthquake activity at Katla

Another quake directly under Katla of 0.9 magnitude at a shallower depth 4.8km.

A bunch under Eyjafjallajokull.

-GY

Last edited by GarageYears; 21st May 2010 at 16:06. Reason: Updated depth to Iceland MET office update
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Old 21st May 2010, 15:35
  #2956 (permalink)  
 
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What better risk analysis can you have than 50 years of records and millions of flights?

The undisputable facts are that NO ONE has been killed in the whole history of aviation by ASH.

You are trying to do a risk analysis on something which to date statistically has shown NOT to be a risk.
Flight safety risk analysis does not work with extremely rare consequences.

What is done is to review much more common outcomes which fortunately for the passenger and crew are measurable degradation in safety (all nicely tided up in the definitions under 25.1309 and the Industry wide CAAM report published by the FAA.

Therfore even sucessful outcomes (the plane landed safely and the passengers changed their underwear) become part of the data. And nobody takes credit for events where nothing happened in millions and millions of hours but instead simply looks at the statistical probability that "any" degradation of safety (according to measured definitions) may happen that contains Volcanic Ash as an ingredient.

I keep saying that the volcanic conditions that we speak of today "will" result in some measurable degradation of safety but no more than the typical risk that we operate within everyday for all other causes (risk is never zero but it is managed within acceptable limits)

Most readers have no idea of what risk is allowed to underly each and every flight and the variable contributions of the causal factors versus time. Just because you identify a newly recognized causal factor "du jour" doesn't mean that you have to manage it to zero to justify to keep flying.
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Old 21st May 2010, 17:13
  #2957 (permalink)  
 
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Originally Posted by peter we View Post
And VA is not the same from all eruptions, some, like this, are far more damaging.
How much damage has this one actually done ? So far no one seems to have any confirmed damage.

Or do you mean that the response to the ash cloud was far more damaging (to the tune of a couple of billion) ?
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Old 21st May 2010, 17:27
  #2958 (permalink)  
 
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an F-18's engine is like a ramjet when compared to todays hi-bypass engines; no wonder it picked up a load of VA!
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Old 21st May 2010, 19:49
  #2959 (permalink)  
 
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Precisely ! The F18s would have been manoeuvring at high speed, high thrust, with no engine bleed worth speaking of, and probably at medium/low level. Under these circumstances they would have almost inevitably been damaged by ash ingestion.
Your average high-bypass commercial turbofan, on the other hand, operates at lower speed and relatively constant thrust, with air bleed. Our manuals tell us that in the event of an ash encounter we reduce speed and increase air bleed (and get the hell out of there).
The British government and authorities at the time of the original ash closure also mentioned an RAF Typhoon that had allegedly been damaged by ash. No doubt that was also manoeuvring at high thrust, low level, which bears no resemblance to the civil jet environment.
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Old 21st May 2010, 20:42
  #2960 (permalink)  
 
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Seismic activity has increased in the last few hours

Frequent but weak tremors in the area around our beloved Volcano in the last few hours, extending also to the proximity of Katla. Hopefully I am just over reacting and it does not mean anything at all.
The increase in seismic activity is objectively a fact in the last few hours but it seems normal activity intensity-wise, the location instead is a bit more worrying as epicentres seem to be moving towards Katla crater, but it could mean nothing, hopefully
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