silverstrata:
can you pls advise how much of the said 12 hours was actually at the contaminated flight levels? 350-200-GL?

First the Finnish F-18s, then NATO F-16s, now RAF Typhoon.

Co-incidence? I don't think so.

The RAF has grounded all training flights (presumably excluding QRA) as a result of this 'unexpected' finding.

Let the Great Experiment begin...
 

I asked yesterday: Science before or after the CAA climbdown? The questions remain unanswered.

How have manufacturers/operators/regulators arrived at these values:

<200 = absolutely safe
200-2000 = safe but needs inspection
>2000 = unsafe?

How do operators know if they have flown through patches/pockets of ash at 200-2000 (which should trigger the special inspection regime "before and after each flight") when aircraft are not equipped with onboard sensors?

And today... what have operators done to comply to CAA’s "Revised Airspace Guidance" requiring airlines to:
· conduct their own risk assessment and develop operational procedures to address any remaining risks;
· put in place an intensive maintenance ash damage inspection before and after each flight; and
· report any ash related incidents to a reporting scheme run by the CAA?
:uhoh::sad::(

Finally, a self-quotation also from yesterday:

My post and all the responses to it have mysteriously disappeared so I'll try again.
I have read all the 116 pages of this thread (not much else to do when you are grounded) and I really want to get to the bottom of it.

So this is my take on the whole sorry saga.

1. The engine manufacturers set a zero tolerance to volcanic ash to minimise the chances of litigation, understandably.

2. The airlines didnt want to set a higher limit for the same reason, also understandable.

3. ICAO tried to accept those above to come up with a figure they could use in their ash avoidance doc 019 but were unsucessful and so they reluctantly published zero as the limit KNOWING it to be at best unrealistic and at worst absurd!

4. All the other safety bodies around the world accepted this as the law KKNOWING it to be based on an unrealistic perameter at best and bloody absurd at worst.

Rules and laws in aviation have to be followed of course. Its not hard to follow a rule, however silly, but its much harder to interpret it, that takes intelligence and common sense.
In my view and with the advantage of hindsight I would say whoever it was(maybe someone can tell us?) who first decided to close European controlled airspace so abruptly, panicked and made a rash decision. Understandable, perhaps. (No doubt it was a committee, not one person, brilliant previous comment-'you never see a statue of a committee!)

SO what should have happened?

First, as soon as the eruption occurred NOTAMS and warnings issued as to where and how far the dust was and what the danger was. Presumably we can tick that box.

Then instead of rushing to judgement and closing most of European airspace KNOWING the law was ultra conservative and KNOWING such a decision would cause utter chaos, all the relevant bodies, 1, 2,3 and 4 above plus the govts concerned should have been consulted beforehand.
Yes this would have taken time, maybe 24 hrs and maybe some answers would not have been forthcoming but a better decision could have been arrived at which could have saved over $2 billion dollars WITHOUT COMPROMISING SAFETY.

The mantra of all the bodies that govern aviation goes like this
'Our primary concern is safety'
That is a given, we all know that and comply with it but just mindlessly repeating it over and over is not a defence.
Sometimes I get the impression it should be
'Our primary concern is protecting our backsides'

'We were just following the rules'
These are among the sad famous last words before a fall.

one-size-fits-all limits are absurd
 

Engines are different.

Specifying ranges of contamination which don't discriminate between different engine technologies is obviously silly. Clearly a piston engine with a filtration system differs from a jet without. One jet design is likely to be relatively immune by comparison with another.

The limits need to be based on the engine, not the airspace. Data from the manufacturer please. Not recommendations, firm and clear limits.

"Safety is the number one priority but...." belongs in the same stash of rhetorical devices as "I'm not a racist or anything but..."

I'd say "over-cautious" was probably an oxymoron, especially in a field of operation with as many variables and natural hazards as aviation, and in a situation with as many unknowns as this ash predicament.

One day the actions of the authorities over the last week might be legitimately criticised as unnecessary - but that will require a fair bit more hindsight than we currently have. We're still in a phase where damage to engines - significant enough to reduce maintenance life if not actually precipitate accidents - could be occurring, and I think a little circumspection and humility amongst aviators is the order of the day.

If it turns out to have been a massive overreaction, then I still say that when you make a mistake it's better to have the ugly numbers for "losses" in the £s/$s column than in the one for human beings. Governments can't win in matters like this - better to be hated for costing money than costing lives.

GE, for one, has transmitted advice to its operators as of 21 April specifying ash concentrations where operation may be conducted as routine, requires additional maintenance, requires yet more maintenance, and is not recommended.

I believe they cannot provide limits, because limits are a regulatory matter and cannot be imposed by an OEM, whether they wish to or not; if you look at any OEM document, any page with a Limitation is invariably marked as being Approved by a regulatory authority.

If OEMs could impose Limits on their own it'd be a license to print money.

Did it ever occur to you that at least some rules are not there to satisfy the legal dept but to prevent us pilots from killing ourselves, our crews, our passengers and anyone living underneath our flight paths?

Don't worry all you children crying over the lack of scientific empirical data about the effect of rarefied VA clouds on turbine engines. We'll have all the data we need soon enough.

I still have a faint hope that it won't be more than we can possibly handle.

Indeed imagine sitting there the EGT on all engines going to limiting value, the acrid smell the knot in the stomach and,..you are cornered by the Alps or Altlantic,...Folks I think we are having a totally new and unprecedented experience in aviation; this one is VERY difficult, Very!:uhoh:

Yes Clandestino, of course most rules are here for our own good, why does everyone keep repeating the obvious? I am referring to this particular rule based on a zero tolerance which even you must admit was virtually impossible to apply.

NOTAMs
 

Regarding airbubba’s NOTAM, with such a complicated NOTAM what is the chance of the wrong safe or not safe areas being given to the pilot? Consider the possible data chain between the volcano and the pilot. Presumably it is something like:-

• Ash eruption density and wind speeds measured by Met Offices
• Put data in a computer model
• Model generates a map of ash concentrations
• CAA(?) by hand (presumably) add a 60 mile margin for error, approximate this boundary into straight lines and hand transfer these lines to the extensive list of coordinates on the NOTAM
• Transmit NOTAM
• ATC/airlines, etc. transfer coordinates from NOTAM to a new map by hand.
• ATC/flight planners, etc. use the new map to tell pilots where they can /can’t go.

Update it all every 6 hours.

Note the ATSIN says that original Met Office maps carries no official status so pilots can not use them to judge safe areas.

Major areas where the process could fall down is:-

• Human error in transferring data at each step
• Forget to add the 60 miles
• Failure to use the latest data e.g. copying over old data
• Failure to adapt to the ever shifting CAA, etc. policy advice
• Met Office computer modelling error
• Met Office measurement error
• Corruption of NOTAM message in transmission (unlikely)

I’d say it’s quite a high risk that the area is wrong but am prepared to be told I have got the process wrong or that there is more automation (less human input) than I think.

Is the NOTAM sytem fit for purpose for communicating this information? Would not direct electronic transfer of the original Met Office map be safer?

Has anyone else noticed?
 

Until this afternoon, every VAA from the UK Met Office VAAC carried a statement: Ash concentrations unknown.

This evening they have dropped that statement.

A change of policy, perhaps?

Anyone know what ash concentration they are now delineating as "Code Red"? Is it perchance different to the criterion they used before Wille Walsh's now famous political meeting of minds?

As both an aircraft engineer and pilot I do feel that so much of what has been written here has been absolute drivel. There are just so many variables associated with the potential for engine damage that I would suggest it's almost impossible to predict.

A good metaphor, understandable by most, would be to compare volcanic ash with potholes in the road. Is a 6in deep pothole bad for your car. Well dependant how many, their dispersion, how fast you hit it, steepness of the sides, etc. etc. etc. One 6in deep pothole on a 200km journey, probably will have minimal effect, whereas a 6in pothole every few yards would. If the sides drop away steeply then it will have more effect than if the sides are quite angled and gentle. The speed at which you hit it will have an effect on potential damage. A 6in deep pothole in a concrete road will probably do more damage than one in bitumen. How many potholes has the car been driven over since last being serviced. Etc.

I do not believe that there is adequate science available to accurately predict damage for every flight undertaken. You need the nature of the ash - silica glass, pumice, water content, etc. their ratios. You need the density of the ash in parts per million. You need the time spent in the ash - whether just transiting a level or continuous flight. You need flight engine parameters - thrust settings, etc. You need a history of previous encounters. You need engine type - some engines may be better able to cope than others. The list goes on and on.

When I flew regularly, risk analysis was considered part of the job, nowadays I suspect less so. And irrespective of whoever you care to blame in the final analysis it's up to the captain to decide whether it's safe or not. What scares people here is, I suspect, an unwillingness to take on that responsibility.

We're beginning to chase our tail on the question Is It Safe to Fly and we need limits from the engine manuafactures.

Many of the demands arise from folks with little experience in managing aviation safety but never-the-less consider themselves experts in knowing when it's safe enough.

In trying to keep it simple, the industry has arrived at today's safety record based on lots of experience including data both analytical, emperical and test based. This is embodied in the regulations including the one most at play here Continued Airworthiness.

Under Continued Airworthiness lots of emperical assessments are offered based on a smattering of test data, real experiences and analysis. Turn the crank and you develop a rational for continued flying with intelligent monitoring as controls are implemented. This is the provence of the OEMs and Operators and has to meet the approval of the regulators to ensure that things do not get out of hand.

Just because the observer of aviation does not see the details or understand the process doesn't mean that it is unsafe to fly. If you really want to audit the process then you have to be as close to it as the regulators.

And by-the-way, such a process of managing safety does not mean that one would expect no incidents of Volcanic ash damage nor symptoms, but it does expect that no harm will come to the passengers.

Fly safe:ok:

We have quantitative criteria for such things as the difference between VMC and IMC. The Met office (of any country) provides us with plan view charts to help us determine where is which.

One of those met offices (the UK one, in this matter) is producing an areal chart which delineates a certain parameter (volcanic ash density, in this case), but it is becoming extremely difficult to obtain a factual statement of what the criterion is which is used in drafting those areal limits.

Can anybody give me a straight answer?

What density is being used to draw those red lines?

Is it different to the criterion which was being used the day before yesterday?

If so, why? and by how much?

A lot of people say you cant be too cautious about safety, you cant overeact on that side of the equation. Well I beg to differ. You can actually jeopodise(someone spell that for me!) future safety by bad decisions even if they are overcautious ones.

The european authorities cried 'wolf' on this one and they wont have the same credibility next time it happens. Many people are going to say 'Here we go again' and they maybe tempted to push their luck when there really is a serious problem, I certainly hope not.

Flying in areas with ash clouds near should probably be treated like icing conditions earlier in aviation. Ice could kill you if you didn't respect it but it could be dealt with if you handled it properly. Little is known about how much ash is too much now. We need to study it and learn from this incident how to deal with it better. We have so much technology now to study it, Drones with monitors would give us a wealth of data. This will happen again, over and over, so we need to know how to deal with it. What would happen to aviation if no one could fly within 100 miles of a thunderstorm?

CFMU now have a rather pointless plotting function showing the routing of any of the 1000's of daily flights filed within Europe. Why cant the ash cloud forecast be overlayed

http://i173.photobucket.com/albums/w...70/CFMUMap.jpg

Not sure what it would achieve - the ash forecasts are also at different levels, also which ash chart are we using?

From alisoncc, above:
It appears to be WORSE than that. Not only is there no accurate PREDICTION. The suggested methods (starting with visual examination post-flight) have already been demonstrated to be insufficient to cover all situations where turbine damage has already occurred. Instrument and engine data recording during flight are also not (it seems) a reliable indication of ash damage.

I've suggested already that filters on heat-exchangers etc. fed via compressor bleeds will contain an accurate record of whatever has passed through the turbine and therefore should be a primary focus of post-flight checks but no-one else seems to consider this important. (Having looked at the recent CAA FOD on the subject of ash, I'm not reassured that bases are covered by the suggested procedures.)

At best, I predict that operators are in for a torrid time covering wildly escalating turbine maintenance costs, quite apart from the downtime waiting for non-available spares.

Cool Guy
Agree absolutely. Legallity to the point of absurdity seems the way nowdays. Buarecrats covering their own backsides is what it is. Ironically, Mount Pinotubo in 1991 they didnt have the b.lls to close the airspace and now they didnt have them to open it. Headless chickens all. :hmm:

The problem has not gone away! Inverness closed to traffic due to ash at 1800 last night and not opening again until 1300 today at earliest. Keflavik is now affected with Icelandair flights between the USA/Canada and Europe operating via Glasgow with a flight from Glasgow to Akureyi for Iceland bound passengers.

NATS are an ANSP (the only privately owned ANSP in Europe) and operate on a licence issued by HMG (well CAA). The government are signed up to the ICAO guidance previously refered to in this thread which states ANY ash, no fly. NATS complied with the conditions of the licence and closed the airspace it operates (on behalf of HMG), as did most of the North European ANSPs. The ball was then in governments courts to change the guidance in consultation with various other bodies. This it eventually did once they'd gathered more facts/data and it was then up to HMG to announce the changes.
Cynics amongst us may say that HMG hid behind NATS skirts so as to make it appear that NATS were the baddies of the piece and HMG rode the white charger to 'save' the airline industry. In reality everyone did exactly what they were supposed to do.

BD

Hello JetII

HIAL report that Inverness, Stornoway, Kirkwall and Wick airports are closed until 12:00 hours today and flights suspended until then.

Please can we defer trying to allocate blame, and get on with developing the the policies and procedures to deal with what may be an ongoing problem. We have plenty of time to deal with blame, but volcanoes wait for no-one.
Alaskan Airlines have had to live with frequent nearby eruptions and have developed some basic guidelines. Why not take a look at them, and adapt/expand/improve them.

Exactly.

WHERE is the hard evidence about the characteristics of the ash cloud as it developed (locations AND particle sizes AND densities per cubic metre - yes - you need ALL of these to come to a valid conclusion about safe routes to fly.

As far as I can tell, if you discount freelance flights by operators which were as much to do with PR as scientific data collection, there was very little extra data collected over and above what was available on 14/4/10. OK - the computer models might have been tweaked but there was (apparently) very little REAL data collection going on in UK, apart from redeploying some cloudbase LIDARs and a few flights by D-CALM and ???. How effective upward-pointing LIDARs are at collecting specific ash data for the different flight levels immediately above, I don't know. Nor how many and where they are. Especially at high ash levels, I don't see how upward-firing LIDARs could cover all the flight levels anyway: 'particles hiding behind other particles' problem.

Hello JetII

People who dare to make unflattering comments about the safety establishment are often branded as 'cynics'. There is nothing wrong with a healthy dose of cynicism as it helps to strip away the b**t and get to the truth. However I prefer the term realist. The opposite of realism is idealism
So this debate seems to be down to the Idealists versus the Realists and I'm quite happy to be the latter.

SimonPro

Alaska airlines have been dealing with this and flying for years. They have built up their own operating procedures.

What comes up time and time again is the lack of knowledge about what concentration of Ash is safe?

Even the latest standards seem a tentative guess rather than figures based on extensive testing.

I am not an engineer or scientist but would have thought specialised engine testing, ground based in a wind tunnel where engines could be run for hours in various concentrations of ash would give a better answer?

Maybe someone could ellaborate on whether this is possible or has already been done?

Pace

Coolguy,

This is not about being right or wrong, it is not about labelling people or 'winning' arguments with your philosophical opponents. What it is about is finding real solutions to a real problem.

If you have any I am sure we would all like to hear.

Forgive me if this has been answered already as I am only joining the debate now.

I am very, no, extremely worried how regulations and best practice have been adjusted to suit and calm an industry which was complainaing of loss of earnings as a result of the recent clampdown. I will be the first to admit that the initial reaction was heavy handed, but I am at a loss as to how we have reached the place we are in now.

Specifically, and most recently, the RAF have grounded their Tornados because of ash deposits discovered in their engines. The BBC have quoted the CAA as saying that these jets suck in vastly more air than civilian airliners and therefore are a completely seperate case and the public need not worry.

Can someone explain to me how a 9,800lb thrust engine on a Tornado needs "vastly more air" than a 115,000lb thrust B777 engine? Even allowing for the high percentage of thrust developed by fans on modern engines, lets call it 85% on the 777, that would leave 17,000lb being produced by the core. That's about the same as an afterburning Tornado. WTF am I missing here? How can ash levels affect a fighter but not even be considered as a risk to commercial traffic?

Fighters are high performance aircraft because they have a very high thrust to weight ratio not because they have massive engines that produce more power than an Airbus. Strap a CF6 to a Tornado and wouldn't believe what it could do. To discount the RAF situation on the grounds of their machines being "high performance aircraft" borders on criminally negligent.

This whole situation stinks. Simply because once again this industry has decided to ignore it's own experience of hasty regulation and incomplete analysis in favour of ensuring revenue continues to spill in the front door. That's for both the airlines and the authorities.

CaptainPaddy

Nothing in aviation happens fast if we had waited "normal" periods for complete analysis and normal regulations by the time they were out there would be no Airlines left in the UK who were still solvent to apply the new regulations to.

Pace

Cool guy,
like you, I have no idea why my reply was deleted.
I think your analysis was partly right, but my point was that RR et al, and BA et al, were publicly saying No-flying when ash was more than zero.
No-one in the CAA could over-rule that.
As neither the engine manuf., nor the operators were willing to work to change the ICAO standards, it needed someone to work through the log jam.
It appears to have been the CAA that forced BA and RR, amongst others, to do the test flights this past weekend. The BA flight was not Willy's idea - it was the CAA's. (Times, 23.04.10).
The CAA bloke in the Grauniad article seems to have taken the initiative.
For once, perhaps, it appears that it was not a Regulator's foul-up, it was a BA/RR et al foul up..
PS - No, I do not work for the CAA!

Paddy - I can make no comment on the possible problems for our motors other than to point out that a mil fighter will spend a significantly higher % of its time in the levels where the ash mostly exists and thus will be exposed to more ingestion than an airliner spending most of its time at cruise.

captainpaddy- with you 100%- I have been involved in industry (all be it not aviation) setting specification levels (and validating them) for 20 years - I cannot understand what has happened here- there is no way that any new levels can have been set and validated in 5 days!!! Has anyone seen any interviews/or documentation that has taken place from/with any of the manufactures of these engines- I would be amazed if anyone in the industry has signed off on these new levels- if they have I think they must be mad- as those signitures are going to be where the buck stops for any claims for damage -or worse. I would have walked away from my job before I would have signed off that specification! What happens next if the testing analysis is undertaken and it is found to be different to the new limits- whoose call is it to change these new limits as it seems that they have been set by the regulators. The usual process below is now in reverse- 1.the science is undertaken 2. measurements presented to regulatory bodies. 3. regulators agree or revise down if not happy with the resluts. This time the tail has wagged the dog. not sure how it can go from here.

Firstly not true. From today onwards, the general wind direction was always forecast to change the situation dramataically. Even for this reason alone I can not understand the rush. We have squeezed out new regulations in record time to give us 2 days extra flying.

Secondly, I'm actually at a loss that so many people seem to agree with the philosophy of rushed regulations. What you are saying is it is better to get flying now, disregarding the lessons of the past, without knowing what the consequences will be in order to keep business operating, instead of doing what we all claim is our first priority - move people and cargo around safely. How can it be safe if it is unknown. That has always been the mantra we supposedly hold oursleves to.

Thirdly, this is not some abstract threat. The Natural Environment Research Council have had D228's and 146's in the air above the UK since Tuesday. They say "Results from both flights revealed the presence of sulphur dioxide and a number of layers of volcanic ash of varying sizes between ground level and 20,000 feet. These discreet layers of fine material are particularly difficult to spot with the naked eye." In other words you could see them if you knew where to look and what you were looking at. We are not talking about invisible, extremely diffuse ash concentrations here. Yet we are flying around like there's no risk.

Fourthly, I agree the RAF may have flown around at low level for longer periods, but the point is that damage was sustained. That means damage is possible. If it was only because they were at low level for 2 hours or whatever, should we then limit holding at LHR to 30 minutes before you hvae to climb above FL200 again to mitigate the risk? You're talking yoursleves into this. If it is only a low level risk, what level is too low and for how long? None of those questions have been answered. At the end of the day if you sustain visisble damage after a particular period of time, you can not say less time means no damage. There is a cumulative longer term effect that must be taken into account.

Lastly, all authorities are going on the basis that the ash concentration is effectively minute and uniform. The NERC flights have proven that to not be the case. Yet they have carried on regardless.

Aviation safety has always been "tombstone safety". When somebody dies they do something about it.:mad: