Ash clouds threaten air traffic

[EGLD]

Personally I'd rather be regulated by over-caution than cowboy when so many lives are at stake.

There's a massive gaping chasm of reasonableness in between those two extremes

[Defruiter]

Statement on Icelandic volcanic eruption: Tuesday April 20, 2040

Response to CAA statement
NATS has received new direction from the UK’s safety regulator, the CAA, on applying restrictions to UK airspace following the volcanic eruption in Iceland.
As soon as revised accurate information is available from the MET Office on the location of the dense ash cloud, NATS will review airspace availability and provide an update to airline operators on any airspace that has been restricted for safety reasons. We will issue a further statement by 2200.

[Ceannairceach]

EGLD - yes, and that gap is filled with lots of stuff called hindsight.

[slip and turn]

Nothing yet from Ryanair ... no flights to Ireland until Friday they were saying earlier I think? How come BA can drop in at Shannon then?

PS I liked the Dads Army graphical anology earlier :p

[ex pom]

Forget your human factors and let commercial pressures lead the way.This sudden change goes against the grain for the wrong reasons !!! :\

Whilst i am glad that airspace is now starting to reopen and we can all travel safely.

Political flip flopping isn't the way :=:=

[BoughtTheFarm]

Until I see some a/c on finals into LHR I wouldn't assume anything. There's a lot going on right now and whilst the change of directive appears to have occured suddenly, I think the most important matter is safe landings into LHR if this is what has been decided. No doubt there will be many 'post match' reviews in the coming days. So for the first time in a while I'm happy to track the inbounds and hope we have no issues.

And is that an Iceland Air that's popping down to LHR? How poetic...

[Phil Rigg]

....... and that 1800Z map shows the London Airports as engulfed in the same alleged 'ash cloud' defined precisely with its accompanying "UNKNOWN ASH CONCENTRATIONS" footnote as we have be looking at for the past six days.

Tell me that NATS haven't been making UK Controlled Airspace closure decisions based on this ill-defined data.....

Clearly the entire aviation industry has an awful lot of homework to do to make a much better go of it next time. As a society we could also look at not being so dependent on intenational air navigation in future.....

Finally, what do we do when the volcano continues to erupt and the wind (meterological or political) changes direction in the next few days!

[Air.Farce.1]

Just a note of caution, until every aircraft lands safely without incident due to volcanic ash, and engines have been inspected as now required by the CAA, we will not know for sure if this was the correct decision.........time will tell :=

[Mountee]

WW interview on sky was impressive, is it correct that the levels of ash in the UK are much much lower than those other times that caused problems?:eek:

[daikilo]

.. and presumably with a full inspection post landing having deliberately flown through identified volcanic ash during the descent.

This is NOT how aviation safety should be.

[Magellan]

@KingCaptain re Walsh:

I know you're joking and yes, agreed, the prospect of WW, Superhero, is, well, diverting.

But things really will surely have reached a pretty dire state of affairs if Walsh somehow comes to be represented as the champion of reason: I've been uncomfortable with BA's strategy right from early this morning.

Media is of course simplistic and populist and seeing the world in black and white without any allowance for particulates means they could now reduce this episode to the level of good guy v bad guy.

For which reason, I'm fully expecting that the flight crew of the Isle of Man meandering BA084 inbound from Vancover but now heading towards what I'm presuming will be a TV-chronicled live LHR landing could finish up being the new tabloid pin-up people of the hour.

They won't want that and neither the industry nor the pax need it.

But all the journalists assiduously reading PPRuNE will doubtless care little about that.

[eagle21]

I am normally not a big fan of WW, but I must admit tonight he was very fluent. I am glad he is planning on investigating the actions taken (or not taken ) by the UK PLC, DFT, CAA, NATS , MET Office.

[Flapskew]

Whoa there folks...good news indeed. However,

there is still ash up there. Ash quanities may be small, but it seems to be down to airlines to risk assess and NOT to fly if it is still too dangerous.

Safe flying!

[TheWanderer]

A report of the scientific flight from Oberpfaffenhofen/Germany with the research aircraft Falcon 20E D-CMET, that was performed successfully yesterday and took measurements is available.
The report can be downloaded as PDF from http://www.bmvbs.de/Anlage/original_1134440/Report-of-Falcon-Flight-19-April-2010.pdf

[scr1]

CAA statment

The Civil Aviation Authority (CAA), the UK’s independent specialist regulator with oversight of aviation safety, today issues new guidance on the use of airspace. This is issued in conjunction with the Irish Aviation Authority (IAA) and covers the Anglo Irish Functional Airspace Block (FAB).

The new guidance allows a phased reintroduction from 2200 tonight of much of the airspace which is currently closed due to the volcanic ash plume over the UK. There will continue to be some ‘no fly zones’ where concentrations of ash are at levels unsafe for flights to take place, but very much smaller than the present restrictions. Furthermore, the Met Office advise that the ‘no fly zones’ do not currently cover the UK.

“Making sure that air travellers can fly safely is the CAA’s overriding priority.

“The CAA has drawn together many of the world’s top aviation engineers and experts to find a way to tackle this immense challenge, unknown in the UK and Europe in living memory. Current international procedures recommend avoiding volcano ash at all times. In this case owing to the magnitude of the ash cloud, its position over Europe and the static weather conditions most of the EU airspace had to close and aircraft could not be physically routed around the problem area as there was no space to do so. We had to ensure, in a situation without precedent, that decisions made were based on a thorough gathering of data and analysis by experts. This evidence based approach helped to validate a new standard that is now being adopted across Europe.

“The major barrier to resuming flight has been understanding tolerance levels of aircraft to ash. Manufacturers have now agreed increased tolerance levels in low ash density areas.”

Our way forward is based on international data and evidence from previous volcanic ash incidents, new data collected from test flights and additional analysis from manufacturers over the past few days. It is a conservative model allowing a significant buffer on top of the level the experts feel may pose a risk.

In addition, the CAA’s Revised Airspace Guidance requires 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.

The CAA will also continue to monitor the situation with tests both in the air and on the ground.


so how will they inspect after every flight when many airlines go to airports were they have no one to inspect them

[Self Loading Freight]

He's just taken a right turn and been put in a hold, is there some high level decision making still going on? Both of these planes went screaming direct to EGLL and EGKK only to get put back into holding.

Surely the last thing you want is putting in some extra time in contaminated airspace? I've avoided bafflement to the best of my ability, but at this point the biscuit is begging to be taken...

[lamina]

maybe the powers that be are now using a different analysis provider-
https://www.cfmu.eurocontrol.int/PUBPORTAL/gateway/spec/PORTAL.14.0.0.P.254.53/_res/100420_1800UTC_draft_Air_ash_concentration_chart.pdf

[Desk-pilot]

The notions that airlines are now responsible for deciding if it safe to fly concerns me. Why is an ash concentration that was considered dangerous yesterday now considered safe tomorrow? NATS and the met-office don't have to answer to shareholders which is why I trust them rather than a bunch of airline execs paid bonuses.

Frankly I'm disgusted by Willy Walsh and BA and the fact that they have leant on the regulator in this way (and I'm usually very pro BA) I have to admire O'Leary (and I'm normally far from a fan of his!!) but actually ironically Ryanair seems far more bothered by the risks of this than BA do - and I never thought I'd say that...

Safety is safety whatever it costs. I personally am not ken to fly tomorrow because I have yet to hear scientific evidence to confirm it is safe.

Desk-pilot

[SweetChariotXV]

He's just taken a right turn and been put in a hold, is there some high level decision making still going on? Both of these planes went screaming direct to EGLL and EGKK only to get put back into holding...

Obviously they are being kept in holds to ensure they arrive after 2100z, and not a minute before!

Even though the decision has been made to reopen EGLL, Nats presumably want to be seen to be retaining the upper hand. Silly really. They should be more concerned with just getting them back on tierra firme - must be some tired crew and pax up there, needlessly holding in my opinion.

[neila83]

How long have those flights been circling for? And now they're still meandering and giving their pax an aerial tour of various bits of Britain, circling here there and everywhere to meet that 10pm openning.

So I'm assuming they all loaded FAR more contingency/diversion fuel than usual, which suggests to me, given the meeting Willie has had this evening, that he rather planned this whole operation, knowing the bad PR the government would get if all these flights were diverted and more pax stranded, when the rest of Europe is open.

Very clever tactics for now, but I will reserve judgement on whether this is the right decision, it does seem aviation safety decisions are being made for political reasons, which puts us on a very very slippery slope we really don't want to be near. However, I do tend to trust Willie Walsh is an intelligent enough man to know a fleet of ash-damaged aircraft would cost far more than waiting till the winds change on fri/sat so I assume he has good reason to believe the air is OK.

[msjcds]

I have heard that BA have about 15 A/C arriving into LHR through the night tonight. Sadly they only have the staff to handle 3 at a time!!:ugh:

[Air33bus]

Is the crew of the planes which are holding,not coming in problems with their working hours?:sad:

[klippy4home]

Surely it is causing more distress to engines holding at 26000 as BAW84 has been around BHX for the past 10 mins, although it is now on a rapid decent so he looks as though he is one of the chosen few.
But is it a good decision to have held them off all this time. Does this make engineering sense...

[Back at NH]

Awful lot of the use of the word "guidance" from the regulator?

[shaun ryder]

I would not even bother thinking about it, your job is to fly the aeroplanes and that is it. You should be positively happy to get the all clear to get back to work. What do you know about what goes on behind the scenes?

I would be far more concerned if I were you about the damage it may be causing ones airline. I for one do not want to be grounded any longer as this could become terminal. Some of us have just dodged redundancy and now this.

The sooner we get an all clear the better.

[slip and turn]

... must be some tired crew and pax up there, needlessly holding in my opinion.Agreed. This seems to have turned out to be a rather sad evening for UK aviation in many ways. The apparent brinkmanship is particularly appalling. Just heard two on about 18 mile approach to LHR ... if so they'll land early :ok:

[Magellan]

neila83: yup, of course it was planned; Denver, Houston, Vancouver, Toronto, Los Angeles, Orlando, Miami, Mexico City. Contingency had to be built in and the planning finalised at least 24 hours ago.

But as deskpilot posted a few minutes ago, an issue forced -- or attempted to be forced -- by someone accountable only to shareholders is no cause for any kind of celebration.

What precedent then?

Be interesting to learn how long it takes for BA to release details of the condition these a/c are in after their extensive jigging around an airspace but recently closed down for being at risk of hazard.

I certainly wouldn't want to be currently in charge of any Speedbird Grand Aerial Tour -- whether the pax are enjoying the view or not.

[peter we]

A report of the scientific flight from Oberpfaffenhofen/Germany with the research aircraft Falcon 20E D-CMET, that was performed successfully yesterday and took measurements is available.
The report can be downloaded as PDF from http://www.bmvbs.de/Anlage/original_1134440/Report-of-Falcon-Flight-19-April-2010.pdf

Quoting from this

Assuming a particle density of 2 g/cm³ our current best estimate for the particle mass concentration in the ash plume over Leipzig is 60 μg/m³. The error is difficult to estimate without further analysis but at least a factor of 2 uncertainty should be assumed. It is possible that higher concentrations occur in other parts of the plume. In fresh volcanic plumes the concentrations will be much higher.

The cloud was 4-5 days old at this point.

[Superpilot]

Speedbird 84 just reported a "burning smell" upon passing a thin layer of cloud between 6000-5500ft when turning right for base leg 27L. Nothing major, no panic, just a smell.

[peter we]

Awful lot of the use of the word "guidance" from the regulator?

Obviously they don't want to liable for any damaged aircraft or passengers. If Airlines want to take the risk, its their problem.

[iwalkedaway]

It appears that WW has played a pretty capable hand today - Gawd knows the situation needed it - but politicians never forget those who have shown up their true incompetence, and if Willie/BA need help at any time while this lot are still in power := he can expect a darned cool reception. BA beware?

[virginking]

Maybe we have reached a tipping point where professionals who understand risk reassert control over the real world from the hands of unelected bureaucrats, jobsworths and political placemen! A lesson for all walks of life. Willie for PM?

[Airbubba]

Looks like they've landed several minutes before 2100Z. Was the hold to sample the ash as someone suggested?

Anyway, hope things are on the way back to normal for us all...:ok:

[STN Ramp Rat]

WW has been engaged in a high stakes game of Chicken with the regulators all afternoon, he launched 24 wide body aircraft to LHR scheduled to arrive between 1900 and 0400 and then stood back to see if the UK government and associated agencies would back down or if they would stand firm and take the flack for the diversions. A number of them diverted before the government caved in.

WW has won the game, who is correct and incorrect will be decided in the coming days

[GAZIN]

I wonder, with some trepidation, what the "intensive maintenance ash damage inspection" is going to entail.
Are we going to have to boroscope every engine post flight? Is it going to be the line engineers fault if an engine fails because it was operated in contaminated air to please the CEO & shareholders? :ugh:

[Back at NH]

The Civil Aviation Authority (CAA), the UK’s independent specialist regulator with oversight of aviation safety, today issues new guidance on the use of airspace....................................................

In addition, the CAA’s Revised Airspace Guidance requires 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.

Anyone seen this "guidance" yet?

[manrow]

Forget the politics, for time being we need to boroscope the engines, and make sure that our moves are safe!

[Denti]

Dunno if it was posted allready, but the report about the measurement flight done over germany is allready available.

Check http://www.bmvbs.de/Anlage/original_1134440/Report-of-Falcon-Flight-19-April-2010.pdf

[Landroger]

While I have skipped a couple of pages because the thread was getting away from me, I would just like to reiterate my Blackwall Tunnel Theory of Authority Mind Set. Its way back in the low nineties somewhere. I suspect that the UK airspace has not been opened because nobody wants to be the person to say it can.

A couple of observations if I may, or should I say a couple more, because that was the basis of my previous post? The Research equipped Dornier D-CALM flew one research sorte on Friday was it? SInce when very little has been heard. KLM and LH flew 'test flights' local to their operations on Saturday? And both said they had found little.

BA flew a 747 for about 3 hours or a little over, basically from LHR to their deep maintenance centre in Cardiff, in an aeroplane due, presumably, for a fairly long hour overhaul? WW announced that no damage had been found, which, one has to assume, included borescoping one or more of the engines and, since their boss was standing next to them, no shortage of qualified engineers slowed them up? Am I okay so far?

One of WW main planks recently has been a degree of management honesty. Believe me, I hold British Management generically in much the same regard as I view England Football, so WW is very much an exception! If he was found to be trying to 'blag' his way back in to the air, by lying about the state of those engines, he would lose far more than he gained on both of his major problems at the moment.

I was concentrating on driving on a prickly, touchy North Circular Road this evening and I may have misunderstood, but I am sure I gained the very strong impression that whatever the Met office and everybody else is basing UK air space closures on, it is not 'areas of ash have been found'. Because no ash at all has been found because there is no-one up there looking for it?

All of the decisions are based on computer modelling? Is that right, some haunted fish tank is guessing where the ash is and hasn't the first idea how much ash there might be in any given place? Is that right? :ugh:

Finally, in reply to 'Stagger' many pages ago;

ETOPS certification depends on a documented IFSD rate of less than 0.02 per 1,000 hours. But this exceptional level of reliability was not achieved with engines that were operated in areas of significant volcanic ash exposure for a period of several days or weeks.

The issue I was trying to get at (and that neila83 has explained) is not whether the ash causes immediate IFSDs - but whether engines operated in this environment have an IFSD rate > 0.02 per 1000 in the coming months.

I have a very strong recollection that the two donks on the ETOPS qualifying B777 had been selected because they were the highest flying hour engines anywhere at the time. They had the most wear and were both further deliberately unbalanced to emulate poorly maintained, very average engines that might well be found in routine airline service. Is this not so? As an engineer, that's pretty much what I would do, because if the engines passed the ETOPS evaluation, I would get a really nice, warm feeling about those engines.

Roger.

[cuthere]

Just as an aside, I'm not sure why the Met Office is taking flack here. Under ICAO/WMO agreements the MO provide VAAC coverage for northwest Europe. Is that not what they've done? Observe, then forecast, the movement of volcanic ash. Isn't that what's happened?

The information they provide is then used by NATS/CAA etc who then decide whether there can be open airspace or not.

The internationally agreed manufacturers' guidance (before this evening's events) was that there is a zero tolerance for aircraft performance in volcanic ash. Therefore, are aircraft manufacturers not to blame for not knowing what their aircraft limitations are? Where does it end?

Unprecedented is surely the word, and instead of looking to blame people, perhaps learning the lessons and keeping them in mind in the event something like this happens again, is the best way ahead.

If a ban hadn't been put in place, and something had have fallen out of the sky, then the same people claiming over-reaction would be asking why airspace wasn't shut. Lose-Lose.


Edit: Landroger, REAL observations of volcanic ash HAVE been made. By the Finnish Airforce, by KLM (near Eindhoven today), by Lufthansa (just south of Hamburg), by Loganair (this very day, at FL170 above Kirkwall), by parachutists (!!!) at FL030 near Peterborough, by the RAF at Coningsby, by an aircraft approaching Newfoundland......I could go on. There have been plenty, PLENTY of reports of ash in the sky.

[daikilo]

If the CAA approves landings it must be with caveats. The London zone is under potential ash cover and will be until at least 21/4 1200.

[Back at NH]

just seen 2 aircraft land at heathrow from my window,

Now that's something that you'd have never thought would be newsworthy!

[bubblesuk]

Perhaps the C.A.A. has spent the last few days doing what many have called for, finding out exactly what is up there and how dangerous it is? You know, just quietly going about their job.

[abfab]

Some of the diverted flights to BRU and SNN are already back in the air and on their way to LHR too!

[Self Loading Freight]

Lord Adonis on R4 now [live transcript - all errors mine]- "there is a differentiation between the dangerous area, a no-fly zone, and a low contamination zone where on the advice of manufacturers and test flights where it is safe to fly. The safety regime has been changed to significant analysis of test flight data and experience of flight, and crucially advice from aircraft engine and airframe manufacturers... before last week, volcanoes weren't a problem in Europe. it's because we faced this act of God that we had to face this problem, and intensive work by manufacturers to establish how it is safe to operate."

Interviewer: Were you aware that there were all these planes in the air heading for London?

LA: Of course I knew this evening, because it was all over the media

Interviewer: Didn't BA tell you?

LA: All I needed to do was turn on the television. The process to clear airspace has been in progress since the beginning of the week.

[BarbiesBoyfriend]

So:

This morning flying is DANGEROUS!, and banned.

Now, flying is safe.

Utter, utter incompetence.

[Re-Heat]

The CEO of Citi-jet released a press statement saying he believes British Airways took "undue risks in conducting test flights " , he also claims to have knowledge that "the aircraft involved in those tests were damaged" . He goes on to say that it appears safety authorities are being pressured by commercial interests. Source : RTE Ireland news at one.
As a result of their engine tests at LCY this morning??? What were they doing I wonder...full thrust into the dock waters while parked in front the A318s...



This morning flying is DANGEROUS!, and banned.

Now, flying is safe.

Utter, utter incompetence.
Air moves around you know...

[cuthere]

Hand Solo, can we have the evidence that the information was duff please?

Have you any grasp of what information was provided by the met men and women to the CAA?

Also, can we have some evidence (just as a bonus) of where the Met said airspace should be shut? Perhaps if their ash dispersion model is inaccurate, as aviators we could all cough up some extra tax to pay for a new one?

[macuser]

i think i saw a senior met man on tv today say they had provided the info NATS' required and that the decision for no-fly 'was outside their (mets) remit'.
i wonder where the dice will roll......

[QDMQDMQDM]

The large bunch of intercontinental flights all now landing at Heathrow launched up to 12 hours ago, which means a decision to launch them in this coordinated fashion must have been taken 18-24 hours ago. It is clear that BA must have decided then that this was all BS and decided to present the UK govt with a fait accompli. At 19-20.00Z tonight they were faced with 20+ BA flights on the doorstep and had to make a rapid decision on what they were going to do.

Big balls for Mr Walsh, that's for sure.

I sympathise with both views. The risk probably is negligible per flight, but it only takes one double engine failure due to a locally dense ash concentration on one of 30,000 daily flights for everyone to howl for heads to roll.

[Back at NH]

NATS is responsible because it imposed a zero flow rate on the airspace it controls

So did the majority of all other European countries. NATS and UK Met Office to blame for them too? Common factor to all would seem to be ICAO?

[BDiONU]

@bdionu - Why no UK-wide airspace shutdown then? Only a zero flow rate.
NATS only have a licence for Controlled Airspace, not the rest. Some countries totally banned flying, some didn't UK was one that didn't. I'm not privy to ministerial briefings as to why HM Government decided not to.

BD

[Joetom]

Will be interesting to see what the maint departments find when doing checks after flight through ash.

Or hav Airbus and Boeing just revised the maint manuals !

[BigDaddyBoxMeal]

Based on the amount of BA long haul flights that have either already landed or are approaching Heathrow, that have obviously been heading towards the UK since this morning.....

Dare I ask who actually decided on the re-openeing of the airspace and the new guidelines for flying in ash. Was it NATS and the CAA based on experts advice and test flight data, or was it Willie Walsh who decided to reactivate his long haul last night/this morning?

[Magellan]

@ QDMQDMQDM:

Government didn't face the decision making process at 19.00Z tonight: the American, Canadian and Mexican Speedbirds were all posted up on the LHR arrivals board before lunchtime today. It's pretty obvious that yesterday (Monday) was spent in planning and then before nine o'clock this morning BA told Lord Adonis to don a spotter's anorak.

[Fargoo]

Will be interesting to see what the maint departments find when doing checks after flight through ash.

Or hav Airbus and Boeing just revised the maint manuals !

Indeed, Airbus procedure on the Bus after encountering volcanic ash is quite thorough and will take some time.

Depends if the crews report encountering ash I guess.

MM 05-51-25-601 if you're interested.

[peter we]

It will be interesting what Ryanair do, they have no pressing commercial need to fly.
By waiting for the winds to clear the cloud away on Thursday/Friday they may save themselves a lot of money.

Not withstanding the fact that inspecting the engines after every flight will blow their business model and profit..

[Right Engine]

Desk Pilot wroteFrankly I'm disgusted by Willy Walsh and BA and the fact that they have leant on the regulator in this way (and I'm usually very pro BA) I have to admire O'Leary (and I'm normally far from a fan of his!!) but actually ironically Ryanair seems far more bothered by the risks of this than BA do - and I never thought I'd say that...

Safety is safety whatever it costs. I personally am not ken to fly tomorrow because I have yet to hear scientific evidence to confirm it is safe.

Ryanair, you might like to hear, pay most of their employees on an hourly basis. If there is no work, there is no pay. It is in O'Leary's interest to sit this one out as he has very little comparative cash burn compared to BA.

Desk pilots are prone to risk aversion I hear. Quite safe sat twiddling with ones pen.

[Stoic]

The notions that airlines are now responsible for deciding if it safe to fly concerns me.Why? Airlines and Pilots in Command have always been responsible for deciding it is safe to fly. Why should it concern you now?

Regards

[saunaboy]

I'd love to be a fly on the wall when the reports from the first required post-flight inspections are submitted. I'm guessing you all saw the scope pics from the Finnish F-18?

The (admittedly unconfirmed) reports of 'burning smell' during descent tonight is troubling. This could backfire quite spectacularly.

[Matt101]

It will be interesting what Ryanair do, they have no pressing commercial need to fly.

What apart from that being how they make their money?

back to topic....

These jets set off when they were under the impression airspace would open this evening. BA are not the only airline flying in. Qatar, Thomas Cook, TUI and some others have all begun approaching LHR.

They most likely took a calculated risk of diversion after the earlier possibility that airspace may open.

Regardless of what you think, financial reasons are not going to force an airline to send their aircraft through areas which they think is going to cost them millions more in damage than the continuing stoppage.

Let us not now use this as an excuse to berate anybody. Airlines are staffed with personnel (or are able to call on the expertise of other people) who are far more qualified to make these judgements than the self proclaimed saviours of aviation on both sides of the line on here.

Slowly though it came, it appears that data has been gathered, manufacturers have been consulted and various boffins have come to the conclusion that it is time for a more directed approach to the airspace closure.

[UAV689]

I can't wait to see this disected in the coming weeks and months as my cynical view point is that

1) BA perform test flights for 3 hours, nothing of note found (aparently)
2) since early this morning flights flying over uk to USA/south America
3) WW launches the fleet, knowing he is invited to cobra in 12 hrs
4) dozen or so BA jets rock up over head, only hrs after airports again shut down
5) WW to goverment, I have 12 jets overhead, running low on fuel. You want to send them to Europe after they have already been flying overhead for an hour or so, surely let's get them on the ground asap.

how can from this afternoon it suddenly gets bad enough to re close the whole uk again, until Speedbirds arrive overhead...oh did I mention there is an election coming up? Voters stuck overseas...media not talking about politics only ash...

Am I being cynical?

[Stoic]

Will be interesting to see what the maint departments find when doing checks after flight through ash.

I presume most prudent airmen will avoid flying through visible ash, so I imagine that this will be an extremely infrequent occurrence.

[Defruiter]

Statement on Icelandic volcanic eruption: Tuesday April 20, 2300

NATS welcomes new CAA guidance and reopens airspace
We are delighted to report that most restrictions on UK airspace began to be lifted at 2134 (local time) this evening, following new guidance from the UK’s safety regulator, the Civil Aviation Authority on restrictions to UK airspace as a result of the volcanic eruption.
Air traffic control services have resumed in the UK with the exception of an area over the north west of Scotland which continues to be affected by a dense concentration of volcanic ash. Based on current information this situation is not expected to change overnight. The situation continues to be dynamic as a result of changing weather conditions and the prediction of dense areas of volcanic ash. NATS will continue to monitor the latest Met Office and VAAC information and the CAA’s updates on the availability of UK airspace.
This brings to an end a period of disruption and uncertainty for air passengers. Our operation is fully staffed and already responding to the backlog of flights entering UK airspace. We will be working with the airlines and airports to resume normal operations as soon as possible.
Due to the scale of the disruption, it will take some time for flights to resume normal operations and passengers are advised to check with their airlines for the latest information about flights.
There are no further operational changes expected overnight and on this basis our next update will be at 0900 (local time) on 21 April.

[TDK mk2]

I am really interested to hear from all those folk who posted on here lambasting anyone who dared suggest that this whole exersize was an overreaction. Will they be strapping into their respective rides when they're next rostered even if the 'plume' is still floating about?? Just curious...

[macuser]

Just watching Sky News. Enormous effort by those involved over ash delays to protect themselves over decisions taken, ie no loss of face. Well done Will.

[Yeovil]

I'm incredibly proud to work for BA, especially tonight. I'm not usually a fan of WW, but tonight he's put the bearded one firmly into the shadows. An incredible piece of brinkmanship.
I'm bloody glad he's working for us.

[Self Loading Freight]

The Irish Aviation Authority website at Irish Aviation Authority - IRISH AIRSPACE AND AIRPORTS CLEARED TO REOPEN (http://www.iaa.ie/index.jsp?p=93&n=96&a=875) links to the current EU no-fly zone as a PDF at http://www.iaa.ie/files/2010/docs/news/20100420082840_100420_1800UTC_draft_Air_ash_c.pdf

http://i290.photobucket.com/albums/ll259/rupertgo/nofly.jpg

[Global Warrior]

The guy from NATS interviewed on sky (sorry dont know his name) did say that no entity had put any pressure on them at all to re-open the airspace........ rather it was a decision that was made based on a better understanding of what is actually in the air based on all the data collected recently.

I guess the inference being........ more knowledge makes for more informed decisions. The position previously adopted was the ICAO NO ash is acceptable, but that was based on minimal, if any data. Now the various parties have data and have raised the bar from NO ASH to whatever ash now and im sure as time goes by that will be updated as well.

[Matt101]

Ryanair have the cash to wait until it really is clear to fly and not make a desperate gamble. I trust their judgement far more than the legacy airlines in this case.

I'm sorry I just think that is an odd point of view.

Ryanair do have substantial cash reserves I agree, but MOL is hardly the type of person to throw them away unless he has to.

Quite frankly I trust the judgement of the airlines (in conjunction with other members of the industry such as the engine manufacturers) far more than that of contributors to this thread.

I guess we'll have to wait and see if BA have just thrown away 50 or so multi million pound engines as all these aircraft come in, or whether they had a fair idea what they were doing, i.e. the thing they have been doing very successfully under one name or another for the best part of a century, flying people safely around the globe, (at times through areas of volcanic activity).

[A4]

So allegations that engines were affected on the BA flight to CWL and
one aircraft on approach to LHR this evening reports "burning smell" during
descent through 5000'.

BS? Scaremongering?

Personally I'm not convinced regarding the longer term affect on engine life.
I just hope this doesn't backfire in about a months time.

A4

[MamaPyjama]

The guy from NATS interviewed on sky did say that no entity had put any pressure on them at all to re-open the airspace

When one of your shareholders throws 12 flights across the atlantic at you expecting a service at the same time as crying to the government.... I'd say thats pressure being put on you

[Pace]

I am really interested to hear from all those folk who posted on here lambasting anyone who dared suggest that this whole exersize was an overreaction.

TDK

Overreaction? would that ever happen with all the scientific knowledge?

Mexican flu! 65,000 estimated deaths. £2 billion on tamiflu reality 340 deaths cant give the Tamiflu away.

Bird flu! what happened to all the birds which were going to invade and kill us?

Global warming man made? How much Carbon has this thing chucked into the atmosphere? Oh well im sure the science will blame man made causes for any temperature increases and raise the taxes to further kill off the airlines.

The list goes on and on.

Shall I start on medicine?

Do we over react? of course not.

Maybe that black cloud was really caused by banging particles together somewhere in Switzerland :ugh:
The only black hole is in our aviation industry.

Pace

[Ella]

I am really interested to hear from all those folk who posted on here lambasting anyone who dared suggest that this whole exersize was an overreaction. Will they be strapping into their respective rides when they're next rostered even if the 'plume' is still floating about?? Just curious...

Speaking as a jet Captain with nearly forty years experience and over twenty years in the left hand seat of jet airliners I am more than delighted to see sensible reason overcome 'Teflon coated beurocracy'.

The simple truth is that we have seen what could have been the end of European Aviation as we know it. Without reasonable assesment risk and flight evaluation based on true fact and not computer models we could have obliterated commercial aviation in the UK. The unpronouncable volcano could, and might contue to erupt for years to come. What were we supposed to do? Go back one hundred years?

I am more than happy to take to the skies with passengers on board, and would have done so from day one. It was obvious that whilst we needed to evaluate the erosion and long term effects on engines there was no reason that so long as we kept well away from the core cloud we were at no more danger than in every day life.

The sooner we stop living in a 'Health and Safety' bubble fuelled by lawyers ever ready to make a buck on the slightest excuse of liablility the better. Sadly I doubt it will be in my lifetime.

[overeasy]

Met Office are publishing charts indicating concentration levels. Not entirely sure what the 'Standard concentration threshold' is but here you go....

Met Office: Icelandic volcano - Ash concentration charts (http://www.metoffice.gov.uk/corporate/pressoffice/2010/volcano/ashconcentration/index.html#D211200)

[banana9999]

So:

This morning flying is DANGEROUS!, and banned.

Now, flying is safe.

Utter, utter incompetence.

How else do you expect it to work?

I am utterly confused. Either it is safe or unsafe and there is a (not necessarily constant) boundary between the two.

I agree with the somewhat wiser posters on this thread that make the point about *some* in the piloting profession getting all upset when their judgement is questioned, yet think they know more than experts in other professions. Disappointing and unacceptable. "Your safety is our first priority (except with it's not convenient)" it would seem.

[macuser]

Just a thought, - in South America there are eruptions in the Andes all the time? How is it handled there?

[Admiral346]

Ella, i agree completely!

And here in Germany, they seem to be all asleep, the report of the DLR plane has been out for hours now, but nothing is happening.

Well, that transport minister of ours has been doing what the advisors told him, from day one. He can't even pronounce ICAO right, so I doubt he even knows what it is.

Nic

[A4]

So looking at the groovy new ash charts, it appears that now and tomorrow below FL200 the ash concentrations are IN EXCESS of the new thresholds...... so why are we operating? Also there is a big black area which is 10 times above "standard" threshold heading our way. Looks like the euphoria may be short lived :/

A4

[BigDaddyBoxMeal]

The million dollar question right now is....

DID one of the BA EGLL inbounds this evening report burning smells during its descent. And if it did, whats the story?!

Someone here must have heard it?

[peter we]

I am utterly confused. Either it is safe or unsafe and there is a (not necessarily constant) boundary between the two.


No, its not black or white, its a risk assessment.

Statistics. Compare it to smoking - will a cigarette kill you? Maybe not but it will increase your chances of dying. Exposure to different levels of ash will increase the probability of damage.

This is obviously what has been decided on - a risk that airlines will take on for themselves and decide if its worth it.

Seems perfectly fair..

[juice]

The Met Office acknowledges the decision by CAA to change the engine tolerance levels for the safe levels of ash ingestion into aircraft engines.

The Met Office is the north-west European Volcanic Ash Advisory Centre with responsibility for issuing the Volcanic Ash Advisories for this area in line with internationally agreed standards and processes as designated by the aviation regulator and industry.

We will now provide timely advice to NATS about the dispersion of the volcanic ash in line with the new engine tolerance criteria. [more]



Met Office: Icelandic volcano eruption (http://www.metoffice.gov.uk/corporate/pressoffice/2010/volcano.html)

[WHBM]

Obviously they are being kept in holds to ensure they arrive after 2100z, and not a minute before!

Even though the decision has been made to reopen EGLL, Nats presumably want to be seen to be retaining the upper hand. Silly really. They should be more concerned with just getting them back on terra firma - must be some tired crew and pax up there, needlessly holding in my opinion.
So let me get this right. NATS didn't want the flights to land because someone couldn't bring themselves to do the authorisation (I doubt the ash conditions improved), but were quite content to have them circling in a holding pattern in the "ash contamination" area.

I wonder what the Daily Mail will have to say about this tomorrow.

[macuser]

At the meeting - NATS, CAA, MET, GOVT, BA and other airlines, who banged the table loudest ?
Who spoke civilservicespeak, who spoke common sense ?

[Airbubba]

So let me get this right. NATS didn't want the flights to land because someone couldn't bring themselves to do the authorisation (I doubt the ash conditions improved), but were quite content to have them circling in a holding pattern in the "ash contamination" area.


Yep, many of the posts have been cleaned off but it appeared the BA aircraft were put into holding at places like LND, then a couple were given direct to EGLL and EGKK with the speed up, then put into holding again, at lower altitude. I have online access to near realtime ADS-B data.

If 2100Z was a hard constraint, it seemed to be waived for the Vancouver bird, I watched it land several minutes before the hour. Someone suggested it was timed for the news at ten, perhaps not that farfetched considering the media circus and brinksmanship going on.

[oversteer]

Do engines have to cool down before they can be boroscoped ?

How long will this add to a flight's turnaround?

[MineDog]

Bij de inspectie van een vliegtuig van de Amerikaanse maatschappij World Airways op de Internationale Luchthaven Oostende-Brugge zijn assen gevonden op de motoren. Dat zegt de luchthaveninspectie.

Het vliegtuig wordt op de grond gehouden. Of er schade is, moet woensdag blijken na een grondige inspectie door een gespecialiseerde technicus. Die wordt nu naar Oostende gevlogen. Hij zou er woensdagmorgen arriveren. Het vliegtuig landde dinsdagnamiddag nadat het was opgestegen in Maastricht.http://content.yieldmanager.com/ak/q.gif




"Er zijn resten van as gevonden maar er is nog geen schade vastgesteld", beklemtoont de luchthaveninspectie in Oostende. "Of er in de motoren schade is, zal pas woensdag blijken."
Het vliegtuig van World Airways was het tweede toestel dat op Oostende landde. Bij een inspectie van het eerste toestel werd geen as aangetroffen. Dat toestel staat ook nog in Oostende. Een tweede vrachtvlucht van World Airways werd dinsdag afgelast door de vondst op het eerste toestel. Dat vliegtuig moest uit Duitsland komen.



Ash found on engine of aircraft landed @ OST. Aircraft grounded. Engineer to be flown over for more thorough inspection of engines.

[Pace]

From a well known Belgian press agency:

Mine Dog

You dont believe everything yoiu read in an unamed press agency do you? Facesaving, scaremongering or headline grabbing come to mind.

Pace

[paidworker]

Google translate the article from Dutch to English before Dishing it, departure and Arrival points are outlined as is the airline ( World Airways ) who it is said have subsequently decided to cancel today´s flights pending an inspection for which they have to fly in an engineer . As you say it could be duff information.

[ILoadMyself]

It was fascinating to watch the Speedbirds, online at flightradar this evening, circling around the UK waiting for the facade to be dropped.

There is no substitute for real life experience and training when it comes to making decisions.

Aircrew in these parts get first class training. The older they get, the more real life experience also.

Unfortunately, British MPs are steeped in training for political survival. They live in a world coccooned from real life. Similarily, the bureaucrats work in a cossetted environment and have no appreciation of how to survive in a commercial environment.

I've worked in the commercial environment and am now enjoying a much more peaceful existence as a bureaucrat so I've got experience of and sympathies with both groups.

By Saturday last, my life experience and training were detecting acquiescence by and the odious whiff of bovine excreta from the Democratic Establishment.

In the absence of any apparent effort to make a meaningful scientific investigation of the possible malignant effects from the unpronouncable volcano's orifice it was left to WW to go for it.

I'm sure he was 100% confident in his decision, bolstered by his training and life experience.

[MineDog]

Pace:

Press agency is Belga, biggest and most known agency in Belgium.

Still: you're right: doubt anything you read, esp. on a rumours network.

[al446]

Here's the translation

When inspecting an aircraft of the U.S. airline World Airways at the International Airport Ostend-Bruges axes found in the engines. That says the airport inspection.

The plane is grounded. Whether there is damage, must appear Wednesday after a thorough inspection by a specialized technician. Which is now flying to Ostend. He would arrive Wednesday. The plane landed Tuesday afternoon after being taken off in Maastricht.




"There are remnants of ash found but there is no damage that" emphasizes the airport inspection in Ostend. "Whether the engine damage, it will turn out until Wednesday."
The aircraft of World Airways was the second aircraft that landed at Ostend. An inspection of the first device was found no ashes. This unit is also in Ostend. A second cargo flight from World Airways was canceled Tuesday by the discovery of the first unit. That plane had come from Germany.

Couldn't you have done that?

[Skittles]

There is no substitute for real life experience and training when it comes to making decisions.

Yes there is - knowledge. Unless of course that experience has even the slightest relevance to the topic in hand, which in this case it doesn't! My 90 year old uncle has all the experience in the world in the textiles industry, but I hardly think it would hold him in good stead if he decided he wanted to be an astronaut.

In the absence of any apparent effort to make any official scientific investigation of the possible malignant effects from the unpronouncable volcano's orifice it was left to WW to go for it.

I'm sure he was 100% confident in his decision, bolstered by his training and life experience.

His training and life experience in ash structure and distribution in the event of the eruption of icelandic volcanoes?This is a forum which completely ignores anyone who isn't a professional pilot. Don't have your fATPL? Then your opinion is worthless.

Obviously that thought train has missed this station. It surprises me somewhat that so many people on here are experts on the Eyjafjallajokull glacier.

[Re-Heat]

I am really interested to hear from all those folk who posted on here lambasting anyone who dared suggest that this whole exersize was an overreaction. Will they be strapping into their respective rides when they're next rostered even if the 'plume' is still floating about?? Just curious...
I will assume that everyone has been doing their job at NATS / CAA and trust their professional judgement. The damage on the F18 was real, and if there is no longer that risk in their judgement, let's proceed with caution.

There is far too much talk of conspiracy, incompetence or allegations of lack of decisionmaking on the thread. I would rather assume people did their jobs to keep us all safe until proven otherwise...rather than the contrary position that many seem to have taken of "let's fly until we find that we are wrecking engines"...

If the above is the attitude, then god help us. I wonder if World Airways has just incurred a $3.2m overhaul cost (a la NASA cost) for their short hop from Belgium to Maastricht today. Fools.

Ella:
I am more than happy to take to the skies with passengers on board, and would have done so from day one.
Are you being disingenuous? Finnish Air Force, USAF, and presumably the ash-covered Scottish Search & Rescue helicopter have all proven that there was a real danger at some point on Day 1. Would you like to fly 200km downwind of the volcano? Of course not.

[mickjoebill]

There is far too much talk of conspiracy, incompetence or allegations of lack of decisionmaking on the thread. I would rather assume people did their jobs to keep us all safe until proven otherwise..

Given that volcanic activity is know to be a problem to air travel, that iceland is a very active island upwind of Europe and that there was NO orchestrated, pre-planned response to measure the cloud and refer to established and agreed levels of risk then the airline industry, aviation bodies and governments are at least lazy if not incompetent.

That there isn't some organisation or another coming out of the woodwork saying "I told you so" is also surprising, perhaps researches thought that the airline industry could look after itself?


Mickjoebill

[Pace]

Would you like to fly 200km downwind of the volcano? Of course not.

ReHeat

But that is the real question we can all see the billowing solid black clouds at the point of the eruption and no one would want to touch that.

But 2 Km, 20 km, 200km, 2000 km ??? downwind? at what point downwind does dispersion make a serious threat to life and limb become minimal to no threat?

Pace

[Re-Heat]

Given that volcanic activity is know to be a problem to air travel, that iceland is a very active island upwind of Europe and that there was NO orchestrated, pre-planned response to measure the cloud and refer to established and agreed levels of risk then the airline industry, aviation bodies and governments are at least lazy if not incompetent.

That there isn't some organisation or another coming out of the woodwork saying "I told you so" is also surprising, perhaps researches thought that the airline industry could look after itself?
Could it be perhaps that the closure of airspace was indeed the planned response, and that all that was lacking was adequate PR. Could it possibly be that the Met Office, NATS and these VAAC units did indeed do their jobs based upon the skills they thought they needed?

There are valid accounts (and air samples) of some real volcanic rubbish in UK skies over the past 4 days. Don't you suppose that this validly supported a framework, using models, that provided forecasts that this cloud remained dangerous.

Here's my point: I'm conservative, and don't know much about volcanoes. The vulcanologists seem to be doing their job in conjunction with the Met Office, and NATS have made a reasonable decision on the basis of that to protect flight safety.

I can't understand the cavalier attitude here when so few are clearly experts, and the evidence to err to conservatism is rather obvious.

My analogy would be that many posters on here would think it OK to takeoff on a heavy flight from Singapore with the torrential rainstorm starting rather than waiting for 10 minutes at the threshold, simply as the last man got away with it. I have but one life.

ReHeat

But that is the real question we can all see the billowing solid black clouds at the point of the eruption and no one would want to touch that.

But 2 Km, 20 km, 200km, 2000 km ??? downwind? at what point downwind does dispersion make a serious threat to life and limb become minimal to no threat?
I'll assume that you've not read anything on here at all as to the effect of silica in the engines of the Finnish F18s, NASA's DC8 in an earlier eruption, the air samples taken by Cranfield, the muck picked up by the Scottish heli crew, and the new evidence that World Airways picked up engine deposits on a short hop to Maastricht today...?

[Julian Hensey]

Does anyone know if Heathrow will stick to being closed in the early hours as per their usual policy or will they change this to enable aircraft to land at 2-4am which is not what usually happens...?

[Re-Heat]

Pace: btw, KEF-HEL is 1,524 miles. I think that is sufficiently far to make the average person with an aviation mindset think about the consequences. That's your 2,000km then.
Great Circle Mapper (http://gc.kls2.com/cgi-bin/gc?PATH=kef-hel&RANGE=&PATH-COLOR=&PATH-UNITS=mi&PATH-MINIMUM=&SPEED-GROUND=&SPEED-UNITS=kts&RANGE-STYLE=best&RANGE-COLOR=&MAP-STYLE=)

Julian:
Link - FlightAware > London Heathrow Airport (London, England) [EGLL/LHR] (http://flightaware.com/live/airport/EGLL) - see for yourself. Nothing inbound apart from DAL3

[brooksjg]

effect of silica in the engines of the Finnish F18s, NASA's DC8 in an earlier eruption, the air samples taken by Cranfield, the muck picked up by the Scottish heli crew, and the new evidence that World Airways picked up engine deposits on a short hop to Maastricht todayThere WILL be plenty of evidence of ash encounters and probably also ash damage so long as the 'new' arrangements remain as they now appear to be.

We STILL have science and measurement deficits. I heard earlier today on broadcast radio some comment about UK 'changing to the US model for ash drift forecasting'. Reportedly, this model is already the one used by Eurocontrol, which (also said) explains the differences between the ash mappings from various sources. Problem is, it's still modelling. If there's concern about flying THROUGH an ash layer, let alone flying IN it and the layers are NOT homogeneous in either extent or thickness (as detailed in the report of the German research aircraft flight linked from here today a few pages back), then clearly modelling does not meet the requirement. ANY mathematical model will produce AVERAGE particle densities over relatively large areas / heights and accuracy will fall off as the time from original, real data input increases.

So where is the planning and finance for direct measurement of ash concentration at a lot of point over UK, from ground level up to (say) FL40? Does the science to do this even exist? Could ATC systems (human and automated parts) actually cope with the additional workload to transform ash-cloud data into instructions for individual aircraft? I can't see any possibility of achieving this safely, or at all.

So the reality MAY turn out to be relatively broad-brush data covering large areas of airspace. I'm thinking, for example, of an 'unsafe' area of 10 by 10 kilometres and extending from FL10 to FL15, moving at maybe 40kph in a known direction. Trying to re-route aircraft around such an area in real time seems completely impractical given current ATC and routeing methods. So what use would more detailed ash data be in practice? The outcome in any case would be closure of destinations and / or routes for hours at a time - very disruptive.

As has been pointed out, the alternative of setting a high particle density as the 'safe to fly' limit and then flying willy-nilly (no pun intended) through whatever ash clouds are there will result in very long inspection delays, followed by (probably) very costly and frequent engine overhauls. (Reports SEEM to suggest that engines ARE damaged by relatively small amounts of ash but tolerate it for some time. NASA DC8 incident report says aircraft flew 80 hours of research at Kiruna and then back to Edwards AFB with no symptoms BEFORE the real damage was actually found. Nevertheless, all 4 turbines had to be rebuilt: cost $2m+.)

At the very least, given the fact that some clouds of ash are quite thin, some on-board ash-detection instrument is vital (if feasible at all!). Then at least in some cases it would be possible to climb / descend slightly so as to avoid flying in an ash layer for long periods. But who's doing the R&D??

Not out of the woods yet, by a long way!!

[jcjeant]

Hi,

Reducing the threat to aviation from airborne volcanic ash (http://volcanoes.usgs.gov/ash/trans/aviation_threat.html)

From belgian newspaper "Libre Belgique" (20/04/2010)

It is beautiful, the birds sing. The quiet fills the skies above Europe hardly touched by the hubbub of this world: the planes can fly? The answers vary with particular airlines, testing support, requesting the reopening of the skies they get little by little.

But the debate rages about many unknowns. "States are working to get quantitative and qualitative observations about pollution and determine a degree of dangerousness is acceptable, says Mr Peter calmly Ghyoot Secretary General of the Belgian Cockpit Association. It is extremely difficult to determine because at the global level today, when there is presence of volcanic dust, air traffic is banned: it is the rule. In fact, there are no standards on the number of grams of ash per m3 air. It does not exist. And even if we knew a number concentrations in the air, it changes all the time. "

Alain Bernard, he rejoices in good volcanologist from the Free University of Brussels, to see the volcanic particles reach our region, is not optimistic: "The rules or criteria to tell the airlines," you can fly because the organic particles are below a certain threshold, it does not. It quoted figures, but we could not verify. Aeronautics grumbles because the aircraft can not fly, but at the same time, we never really tested what degree of problem with a dilute cloud of ash. There was absolutely no objective criteria to say "Here, the concentrations are such a level and you can fly. "There are research aircraft that made the tests, but nothing can make, because we did not test the tolerance of prolonged engine aircraft vis-à-vis volcanic ash. "

For his part, Gerald Ernst, a volcanologist at the University of Ghent, enraged. There are about ten years, he had already warned against this kind of phenomenon and its impact on air traffic. Specialist physical dispersion of explosive eruptions and volcanic ash, he helped set up an alert system in Iceland, but his research, like that of his colleagues, suffered a setback due to lack of resources and interest. He points the finger when the unpreparedness about this event: "We did not models that take into account the reality of the eruption. This model has been developed for the Chernobyl disaster and it does not consider the dynamics characteristic of the explosion. An eruption is not Chernobyl and the cloud is not dispersed passively by wind. And there is another aspect not taken into account: it's like a rash happens near a glacier, he yal'interaction between lava and ice, and it explodes. Very fine particles then form aggregates, pellets of ash and ice. These flakes falling so quickly. A good Part of gases and ash are discharged early, causing damage mainly in Iceland. But the problem is that the ice clouds the satellite and it causes uncertainty about the amount of aggregate, gas and ash that contains cloud "

And Gerald Ernst to suggest a quack occurred ten years ago with the current forecasting system: "In 2000, there was an explosion in Iceland. A cloud moved over the north. A research aircraft from NASA to then walked around 1 800 km north. According to the simulation made at the time, it should not be a cloud of ash. They are still spent in the middle and it cost four to five billion dollars repair the aircraft. It shows that the model was not developed and they use the same model today. There should have been laboratory experiments to calibrate the instruments. It has not been done: no funding. "

No doubt the magnitude of the economic mess will soon present standards and research on the subject.

[professorsabena]

I think the debate has polarized around caution vs poor interpretation of the information. However please bear with me. I fly more than 250K miles both as a revenue and non-rev passenger each year.

I think there is a clear case here for one thing - MORE RESEARCH. My argument is that judging from the data from D-CMET the concentrations of ash vary widely even at the predicted levels. Therefore it would be safe to conclude that the mathematical models combined with met info are not sufficient to make cast iron decisions. Reading through this thread the vast majority of people agree. Neither do I think the decisions left to the Pilots alone is a safe decision - they are not being provided with enough tools to make the "right" decision. Despite a significant amount of data that points to the damage that can be done, the impact of lesser concentrations of ash remain hard to comprehend. The hard data tends to deal with the catastrophic type situations (BA009, NASA's DC8 and the F/A18s).

We also know that we are dealing with the shades of grey. Personally I would feel a lot better if there were better ways to continue to measure the particulate concentration at the different flight levels, with the goal of creating/establishing some safe corridors and flight profiles on a real time basis. We have seen from the Germans that these concentrations of ash are not consistent at particular flight levels therefore to continue flying constant flight levels may be (I stress maybe) creating opportunities for ash encounters. However I don't see that the type of different flight profiles flown by D-CMET other than the one time event are being encouraged. This to me is where the authorities who have the resources should be deploying aircraft equipped with the type of equipment on D-CALM and D-CMET that can measure the particulate.

If for no other reason than this is a unique opportunity to create a lab to examine the situation for future occurrences - we should be encouraging science to get involved in this situation.

With that said - may I just hope that we can get a degree of qualification rather than conjecture into this process. My one nagging fear is that we are creating a situation of reducing life of an aircraft's engines that will result in premature failure - long after the equipment has lived its primary life in a well cared for home and gone to that lesser grade second cousin three times removed that you don't want to acknowledge and the EC occasionally blacklists.

Cheers

[alwaysmovin]

I just want to say as an ATCO..respect to those pilots who have flown today...basically through the unknown....no matter what all the 'experts' say...nobody knows what could happen and still you went to work! Have to say even on the ground it felt a bit strange.... esp giving pilots VFR clearance and then IFR passing fl200...later Fl250 (in Germany)....so respect and well done!! Not sure I would have been so brave!!

[AnthonyGA]

I just want to say as an ATCO..respect to those pilots who have flown today...basically through the unknown....no matter what all the 'experts' say...nobody knows what could happen and still you went to work! Have to say even on the ground it felt a bit strange.... esp giving pilots VFR clearance and then IFR passing fl200...later Fl250 (in Germany)....so respect and well done!! Not sure I would have been so brave!!

The pilots operate with at least some knowledge of the risks involved. The same is not true for any passengers they carry, who simply trust pilots and the airline operator to maintain the highest level of safety. And unfortunately, as long as there is ash in the air, the usual highest level of safety is not being maintained, although the revenue stream of airlines is being maintained. Recent events have shown that there is no danger that cannot be ignored if there's enough money at stake.

Fortunately nature has cooperated slightly and the ash concentrations seem to be diminishing. Hopefully nobody will be killed by airline greed on this pass, but only time will tell.

[cockpitvisit]

And unfortunately, as long as there is ash in the air, the usual highest level of safety is not being maintained, although the revenue stream of airlines is being maintained.

Well, you can also say that the highest level of safety is not being maintained as long as there are planes in the air.

Apart from safety and the revenue stream, the needs of passengers are important too. Thousands of pax are having their business and vacations ruined, and lifetime wasted.

Let's see, a life expectancy of 80 years means 30000 days. If a pax gets delayed by 3 days, he has lost 1/10000th of his lifetime. Sure, some will enjoy the unplanned extra vacation, but I am pretty sure that for the majority of passengers, this is wasted time coupled with extra expenses which will make their life worse in the future. So for every 10000 delayed passengers, one life is practically lost by such a delay (and we are not even talking about actual health damage due to stress, lack of medication etc.).

If flying through ash means bringing pax to their destinations 3 days earlier, it pays off even if one plane in 10000 crashes because of a higher danger level.

[AnthonyGA]

Well, you can also say that the highest level of safety is not being maintained as long as there are planes in the air.

But there's a difference here: the general risks of aviation are well understood and quantified, whereas the risks of volcanic ash are not. It's clear that volcanic ash is a bad thing, but the maximum allowable ash concentration for a given level of safety is unknown. In aviation, if you don't know, you don't go, which is what has made air travel so safe. In this case, that general guideline is being ignored, for the sake of money.

If flying through ash means bringing pax to their destinations 3 days earlier, it pays off even if one plane in 10000 crashes because of a higher danger level.

You realize that one in ten thousand means a dozen or so crashes per week, with more than a thousand people dead, right?

[Hand Solo]

In aviation, if you don't know, you don't go, which is what has made air travel so safe.

I disagree, that has never been the approach in aviation. What has been the approach is a graduated approach to risk, not a risk free environment. It is abundantly clear that the ash cloud is not having the expected effect on high-bypass ratio turbofan engines. If you want sound data on what is an acceptable level of ash and what it's long term effects are you will not get them from mathematical modelling, you will only get them from empirical evidence, and that means going out there and flying. The airframe and engine manufacturers can only gather so much information and experience from predictions and test flying. The rest does, and has to, come from airlines flying and reporting back their findings. It has always been the way, and it will always be the way, simply because an exhaustive program of testing by manufacturers whould be prohibitively lengthy.

[Mad (Flt) Scientist]

@Seat 32F

Also, the normal rules for safety for dealing with engine failures are designed around the assumption that most engine failure scenarios are independent - designers go to great efforts to make the two (or more) engines on a multiengine plane as independent from each other as they can. And operational and maintenance procedures exist to try to eliminate any remaining "common causes" (things like dont change two at the same time, in case the same maintenance error affects both, and so on).

Now, if a plane fly through a dangerous level of ash, that condition applies to all engines, and all may fail (or be affected) equally. So the aircraft may not have the option for a flight at a lower altitude; it may become a rather large, and not very efficient, glider. Which is not a good outcome, from a continuation of flight perspective.

[Nemrytter]

Hello JetII

[jcjeant]

Hi,

Hand Solo

you will only get them from empirical evidence, and that means going out there and flying. The airframe and engine manufacturers can only gather so much information and experience from predictions and test flyingTest flying .. with passengers ?
Methink actually with your theory .. passengers are "beta testers" and so must be paid instead paying for fly :)

[Hand Solo]

I think you misunderstand. Test flying is done by the manufacturers, without passengers. The vast majority of their in-service data comes from the airlines. The manufacturers simply do not have the time to put a million hours on an engine before making a decision.

[L337]

Latest CAA press release is interesting, and worth the read.

The Civil Aviation Authority (CAA), the UK’s independent specialist regulator with oversight of aviation safety, today issues new guidance on the use of airspace. This is issued in conjunction with the Irish Aviation Authority (IAA) and covers the Anglo Irish Functional Airspace Block (FAB).

The new guidance allows a phased reintroduction from 2200 tonight of much of the airspace which is currently closed due to the volcanic ash plume over the UK. There will continue to be some ‘no fly zones’ where concentrations of ash are at levels unsafe for flights to take place, but very much smaller than the present restrictions. Furthermore, the Met Office advise that the ‘no fly zones’ do not currently cover the UK.

“Making sure that air travellers can fly safely is the CAA’s overriding priority.

“The CAA has drawn together many of the world’s top aviation engineers and experts to find a way to tackle this immense challenge, unknown in the UK and Europe in living memory. Current international procedures recommend avoiding volcano ash at all times. In this case owing to the magnitude of the ash cloud, its position over Europe and the static weather conditions most of the EU airspace had to close and aircraft could not be physically routed around the problem area as there was no space to do so. We had to ensure, in a situation without precedent, that decisions made were based on a thorough gathering of data and analysis by experts. This evidence based approach helped to validate a new standard that is now being adopted across Europe.

“The major barrier to resuming flight has been understanding tolerance levels of aircraft to ash. Manufacturers have now agreed increased tolerance levels in low ash density areas.”

Our way forward is based on international data and evidence from previous volcanic ash incidents, new data collected from test flights and additional analysis from manufacturers over the past few days. It is a conservative model allowing a significant buffer on top of the level the experts feel may pose a risk.

In addition, the CAA’s Revised Airspace Guidance requires 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.

The CAA will also continue to monitor the situation with tests both in the air and on the ground.


Link to the article:
CAA Press Release (http://www.caa.co.uk/application.aspx?catid=14&pagetype=65&appid=7&newstype=n&mode=detail&nid=1862)

[peter we]

In addition, the CAA’s Revised Airspace Guidance requires 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.

Basically, fly at your own risk - if you think its safe, go ahead.

We will have the answer to the question of the economic cut off point of flying through dust. Using real aircraft and real passengers.. I wonder how many passengers are going to voluntarily take part once the desperate have been repatriated.

[rgsaero]

So the CAA seems to agree that more research is needed! It, and the other regulators worldwide are only about 28 years too late to have avoided massive cost and inconvenience to Britain and the rest of Europe.

At post No 1970, before anyone "reopened" our airspace I wrote -

"Far more important than what is happening at the moment is what WILL happen in the coming months. The industry must undertake detailed research to find out what its equipment will "tolerate", while national and international authorities MUST put in place systems to ensure that any computer models of future events can be checked in detail by actual sampling to ensure that a vital industry is operated on the basis of knowledge rather than computer guesstimation.

Had such work been done on a regular basis since 1982, we would have 28 years worth of useful information instead of very little."

I wonder when they will start or have they? That's where the industry has to put the pressure now.

Given that the CAA is one of the few, if not the only "safety regulator" tasked by Government with making a profit - yes, 6% on turnover - surely it should be putting in place a PROPER system, and b****y fast, not least because the next door volcano could go off at any minute!

[airvanman]

"Thomas Cook TCX952P registration G-JMCF (Boeing 757-28A) just made a u-turn to Manchester, it was out over the North Sea off Nofolk/Suffolk, it reported to London and Manchester Control it had an engine bleed problem after an 'intense smell of volcanic ash in the cabin during the climb between FL160 and FL200."

More details at:
http://www.airnavsystems.com/forum/index.php?topic=4703.540 (http://www.airnavsystems.com/forum/index.php?topic=4703.540)


Just noticed this! True or just :mad:?

[Pace]

The new guidance allows a phased reintroduction from 2200 tonight of much of the airspace which is currently closed due to the volcanic ash plume over the UK. There will continue to be some ‘no fly zones’ where concentrations of ash are at levels unsafe for flights to take place, but very much smaller than the present restrictions. Furthermore, the Met Office advise that the ‘no fly zones’ do not currently cover the UK.

ReHeat

But that is the real question we can all see the billowing solid black clouds at the point of the eruption and no one would want to touch that.

But 2 Km, 20 km, 200km, 2000 km ??? downwind? at what point downwind does dispersion make a serious threat to life and limb become minimal to no threat?

Pace

I'll assume that you've not read anything on here at all as to the effect of silica in the engines of the Finnish F18s, NASA's DC8 in an earlier eruption, the air samples taken by Cranfield, the muck picked up by the Scottish heli crew, and the new evidence that World Airways picked up engine deposits on a short hop to Maastricht today...?

Reheat

Obviously The CAA have not either?

Pace

[PENKO]

Indeed I-FORD. So, are all those who were in favour of grounding aviation till the last ppm of ash was out of the sky refusing to fly today? :)

[protectthehornet]

flying has always had an eleement of risk. and the person who has the final say is the captain.

what I would like someone to do is use some, yet to be made, gadget to tell the pilot about the healthiness of the air being sucked into the engine. sensing the particulate matter and displaying in EZ to understand terms/images if one should continue or turn around.

a parakeet in the coal mine for jet engines.

[A I]

Let's rename the CAA Pontius Pilate shall we? They (and the Irish authorities) can have this year's Buck Passing award.

A I

[tocamak]

Ella:
I am more than happy to take to the skies with passengers on board, and would have done so from day one

So you actually knew from day one that there was no risk. On what was this based.

[Back at NH]

So as the ash cloud becomes even more diffuse and withdraws from UK airspace (as evidenced by the latest VAAC charts), King CAAnute announces the salvation of British aviation?

Has anyone got a link to this revised airspace guidance yet as we can't rewrite our operational procedures against the specification of a press release.

[NiteKos]

It would appear that the issue here was not about how much ash there was in the amosphere but where it was. The VAAC model was computer generated and was looking more rediculous by the day as it expanded mathematically over to Newfoundland and into Russia. This was the problem as the satellite imaging used by the FAA showed the ash in a completely different area. Europe started using the satellite imaging as soon as they realised the conflict but because the VAAC couldn't back down we had the farce of Adonis and his advisors insisting on using the VAAC model when there was clearly a vast confliction in the data being provided. A final compromise was thrashed out last night after enormous pressure from the airlines that resulted in a extended red line being drawn round the satellite images.
Standby for massive compensation claims and heads rolling, a typical UK over reaction based on flawed data.

[Snoop]

Does anybody know the current state of play inside German airspace?

Is it still VFR below fl100 only?

[ORAC]

That'll be a model from the Met Office, which also produces the models used to predict Global Warming then? :hmm:

The airlines don't come out of this smelling of roses. They're the ones who have dragged their feet for years to prevent a safe ash level being set...

Guardian: Why airlines resisted setting safe dust level for flights – until now (http://www.guardian.co.uk/world/2010/apr/21/airlines-flights-ban-airspace)

[possibleconsequences]

Interesting that it was NATS that effectively closed the airspace on thursday by issuing instructions to NATS controllers not to accept IFR flights in controlled airspace (no such instructions to non NATS units until friday), yet it is now the CAA who are stepping forward as the regulator to re-open airspace.
I personally spoke to a CAA inspector on friday who said , and i quote ' we have not issued any mandatory instructions but we are recommending that NATS guidelines are followed' .

When did the CAA step in?

Perhaps we can ask Harriet Harman?

[Re-Heat]

a) It was not a UK-only reaction; decisions were made across Europe as well

b) Met Office modelling shows the cloud becoming more diffuse as time progresses - hence why we now find airspace opening in conjunction with changed risk assessments on engine tolerances. I still do not see how that possibly indicts the decisions of the last 6 days as bad. I don't see this as being ridiculous at all. Met Office: Icelandic volcano - Ash concentration charts (http://www.metoffice.gov.uk/corporate/pressoffice/2010/volcano/ashconcentration/index.html)

c) North Atlantic weather patterns have not dissapated the cloud, unlike eruptions from Redoubt, Alaska or other volcanoes have

d) Empirical observations have vindicated the modelling: see where their own heli was grounded on the way to make the observations Met Office: New observations of volcanic dust (http://www.metoffice.gov.uk/corporate/pressoffice/2010/pr20100420.html)

e) Further empirical observations here: Met Office: Icelandic volcano imagery (http://www.metoffice.gov.uk/corporate/pressoffice/2010/volcano/observations.html)

f) I don't see any conflict between the satellite images (which the Met Office has also published throughout) and the forecast maps; empirical evidence has supported the presence of thinner volcanic ash in areas not shown on the satellite map, the same thin ash layers which caused Finnish F18 engine damage

Edit: g) Read ORAC's article link


I am happy for the CAA and NATS to make a professional judgement that flight is safe in the environment today; I don't see that process as having disproved any of the past 6 days' decisions whatsoever. That process was necessary if insufficient tolerance data was available, and the ash cloud was more concentrated until today.

On the contrary, the attitude of many here seems to be no different from the psychological state of bull market participants in the stock market who match their ideas to facts as they perceive them, rather than recognising changed environments.

I still can't see why people see a conspiracy, particularly on the side of conservatism (when it is usually levelled at bullish companies who are alleged to compromise flight safety...)

"Belief in conspiracy theories can be comforting. If everything that goes wrong is the fault of a secret cabal, that relieves you of the tedious necessity of trying to understand how a complex world really works. And you can feel smug that you are smart enough to “see through” the official version of events."

Safe flying

[Airbus Unplugged]

Perhaps we can ask Harriet Harman

No, don't. I can't bear the sound of her voice. Nothing gives me greater solace than the thought of her sitting in the benefit office on May 7th.:ugh:

I would have been happy to fly from day 1. I have 25 years of experience of flying in all kinds of crap. The pilots are the ones who decides when and where it's safe to fly aeroplanes, not faceless bureaucrats.

[wonderbusdriver]

Check here for the latest:

dfs.de (http://www.dfs.de/dfs/internet_2008/portal/english/start/index.html)

It´s still VFR below FL200 in most places.
Did CVFR into FRA yesterday.

[Re-Heat]

I would have been happy to fly from day 1. I have 25 years of experience of flying in all kinds of crap. The pilota are the ones who decides when and where it's safe to fly aeroplanes, not faceless bureaucrats.
Which airline do you fly for again? I'll make a note to avoid paxing on it. I assume you also ignore the faceless bureaucrats who forecast storm cells as well, right?:ugh:

Day 1 in Finnish airspace, 2,000km from the volcano? I'll leave you to it.


ORAC
The airlines don't come out of this smelling of roses. They're the ones who have dragged their feet for years to prevent a safe ash level being set...

Guardian: Why airlines resisted setting safe dust level for flights – until now
Good point, useful article with some good journalism (despite the publication!)

[Massey1Bravo]

"Thomas Cook TCX952P registration G-JMCF (Boeing 757-28A) just made a u-turn to Manchester, it was out over the North Sea off Nofolk/Suffolk, it reported to London and Manchester Control it had an engine bleed problem after an 'intense smell of volcanic ash in the cabin during the climb between FL160 and FL200."

I have a feeling some airlines are just waiting to be sued in the American courts over knowingly flying into ash if a subsequent accident happens due to engine failure/rollback and ash, no matter how little, is found in the engines..... :uhoh:

[freddyfokker]

As Captain, I am legally responsible for the safe preparation and execution of any flight I undertake.

As we are still in a volcanic ash cloud, ( it has not gone away) is it unreasonable for me to see the information that has led to the resumption of flight, especially as the ops manual states avoid flight into volcanic ash. If I have an incident who is to blame?

I am happy to fly but would like a little more data to hang my hat on

[peter we]

Would it be worth it.. It's nearly 9am and Heathrow is virtually dead and the arrivals board says "cancelled" for about 90% of flights.

There is no point ruining the entire fleet on test flights is there?

Ryanair are not going to take part in the experiment apparently flights are cancelled until Thursday (when the wind is expected to blow the last of the cloud away.

[Re-Heat]

I am happy to fly but would like a little more data to hang my hat on
Agreed - much as I am defending NATS/Met Office in this, their PR has been appallingly bad in eloquently communicating what data they have been using, which has spread the fans of the great conspiracy theory.

[Pace]

not faceless bureaucrats.

Airbus unplugged

Well said! Maybe HH can spearhead yet another state funded quango to write a report on the internal structure of volcanos. Spearhead is the appropriate word right down its opening.

Poor old aviation has been loaded with such huge costs from a mass of faceless burocrats from every direction that it is fast becoming an awful business to be in.

Pace

[surfcat]

Maybe the government should fund this and the huge costs to the aviation industry from the huge revenue it gets from its so called "Carbon Taxes" to research the biggest Carbon producer into the atmosphere of all?

Pace

I entirely agree. The government should use some of the VAT and fuel taxes which airlines pay to help make up for all the losses incurred. Oh, wait....

[ZQA297/30]

When can we expect to see "approved for flight in volcanic ash concentrations of xxx/m3 or less" in our AFMs?
I like brooksjg's suggestion as an immediate check on ash encounter (especially inadvertent). Should be possible to differentiate between bugs and rocks by simple visual. Bad rocks and benign rocks might need microscopic exam.

[brooksjg]

All sorts of things, probably including insects, could potentially cause False Positives.
Depending on the previous filter replacement cycle (ie. when clogged with non-ash material and therefore doing their job), you could either set a maximum for ALL air contamination permitted on one flight and quarantine the aircraft whenever it was exceeded, or find that for filters tested after one flight only, the level of contamination from non-ash causes will always be insignificant. Makes no impact on the effectiveness of the filter testing as a first-line defence against ash in the turbine, I don't think.

Might be a good idea to monitor ALL the different crud passing through the turbines, anyway!

On further reflection, my suggestion seems so obvious (and already widely done in other contexts) that it's hard to understand why it's not been done with volcanic ash or other intake air contaminants since forever! Next thing, some engineer from BA Cardiff will pop up and say they've actually been doing it all the time (or at least since the WW PR flight! :sad:

[100above]

As someone rostered to operate 4 sectors this afternoon, I've been trying to gather as much updated info as I can. Having just been on to the CAA website, I'm interested in the CAA requirements that airlines are to perform "an intensive maintenance ash damage inspection before and after each flight". I expect to have company guidance on this later today, but it isn't immediately clear to me which airspace this applies to, given that there still appears to be areas with low concentration of ash over some parts of the UK today and that the areas affected are constantly changing. Glad to be back flying, but haven't seen much discussion of this inspection requirement.

[iwantmyhols]

very surprised to hear (bbc1 news) that it was in discussions with manufactures of the engines that the new policy was reached. I would be very amazed if any of the manufactures have put the signitures on this new policy. It would take months of validation work to come up with a level that was safe- not 5 days- I have worked in validation of experiments (all be it not in aviation) for 20 years- this is just not possible. I would love someone during a tv interview to press for the new ppm 'safe levels'. I have no idea if the skys are safe to return to, I have no idea if they were ever unsafe- but I DO KNOW THAT a new policy based on a diff safe limit found by experimentation cannot be set in 5 days.

[DespairingTraveller]

I've read most of this thread, and have previously decided just to hold my tongue for fear of getting flamed, or moderated.

It seemed to me all along that the response to this (or indeed) any volcano's eruption should have followed the following, fairly simple, train of thought:

1) Does flight through the affected airspace pose an unacceptable risk of damage sufficient to cause an imminent loss of life? In this context, "imminent" means that the loss is likely to occur during either the current flight or any subsequent flight(s) prior to it being possible to adequately inspect and repair said aircraft. In this case there is a clear case for airspace being closed to traffic.

2) If (1) doesn't apply, then the event is not an immediate safety of flight issue and airspace should not be closed. Decisions then become commercial. It must be an operator's prerogative whether or not it is to its benefit to ground its aircraft and avoid increased repair costs or to fly and accept that there will be increased wear and tear. That is not to say that there is no place for the regulator in that process. It is entirely proper, and indeed should be expected, that the regulator impose a more stringent inspection regime on aircraft that are known to have been exposed to unusual atmospheric contaminants.

We now seem to have arrived at a modus operandi that reflects that train of thought. Unfortunately, getting there has been a painful process which has cast no credit on government, the regulators, or indeed the aviation industry:

a) Government, because it sat back for too long allowing the aviation authorities to take decisions with major impacts outside their field of competence. Like it or not, a decision to impose a prolonged closure of airspace over an entire continent should not be taken purely in an aviation context, without regard to other effects. In the modern interconnected world, such a closure has financial, social and economic consequences far beyond that restricted regime. Most directly, as any closure extends, we should expect that people will die in accidents using alternative transport or for lack of medication or treatment, but there will be bankruptcies, economic disruption and so on. It is explicitly the role of government to balance conflicting interests in such cases.

b) The regulators, because their preparations for such events had almost certainly not been adequately stress tested. I will be amazed, and rather disturbed, if it subsequently emerges that the ICAO and others had realised that the procedures they put in place could lead to the shutting down of air traffic over one of the world's most economically active regions for nearly a week. Especially as a result of the eruption of a volcano smaller than the one they used as an example in their policy document! The Met Office hardly emerges with any credit from this process either. How can the VAAC be satisfied that it has discharged its role adequately when it has issued charts showing the “boundaries” of contaminated regions accompanied by the clearly contradictory statement that concentrations within those regions were unknown? And why had it not established any methodology for actually checking its predictions against measured data? Or against the predictions of other forecasters?

c) The aviation industry, because there seems to have been so little prior investigation of the physical effects of this phenomenon. How can airframe and engine manufacturers have issued documents stating that should be no flight through ash-contaminated airspace with a straight face? Surely that was a prohibition honoured more in the breach than the observance, since a zero concentration of ash is clearly never possible, mathematically or practically, in the atmosphere of a planet whose geology is driven by plate tectonics.

Despite newspaper terminology, this has not been a "shambles" or "chaos". And I am very glad that I haven't been caught up in it personally. But it has been woeful to watch. We weren't struck by an asteroid, folks! A routine, well-understood, geological event occurred in one of the richest, most developed, most sophisticated and technically capable parts of the world, and the various authorities' best response was, in essence: "well, we don't know what the actual effects are!"

And this in a field where the maxim: "prior preparation prevents p**s poor performance" is supposed to rule. Spare us....

[horsebadorties]

Irish Aviation Authority - Document Details (http://www.iaa.ie/index.jsp?p=93&n=97&a=225&pp=93&nn=97&lID=816)

[rab-k]

LOL...

The CAA/NATS would I'm sure have preferred to say something along the lines of "there's ash out there guys'n'gals, check the VAAC as to where it is forecast to be, launch at your discretion", however I'll bet the operators took the view "we're only going if you say its safe to go and if it turns out it wasn't safe then we're coming after you"; the blood-sucking lawyers will have had a field day sorting out where the responsibility rests in the event of some poor sod turning their 747 into a lawn dart.

The whole thing was an exercise in ass covering in the event of an incident. I suspect the operators could've had unrestricted movement from the outset if they'd stated that they wished to continue operating normally, and would accept 100% responsibility for the safe operation of flights through airspace forecast to be contaminated with ash. However, it would appear that they didn't, and (some) are only too quick to start pointing fingers elsewhere. A case of wanting to have one's cake and eat it me thinks.

Wonder how WW will feel two days hence if half his fleet is grounded because of silica contamination of fan blades...:hmm:

[brooksjg]

DespairingTraveller:

Very well put, especially para 2c.

Interesting to see how all these 'procedural deficiencies' will be corrected (or tucked back beneath the carpet).

[no sig]

Considering the unprecedented nature of this event, the fact that we, most certainly, had to suspend operations in the first two or three days after the ash reached the UK. I think everyone has done well to find a way through the problem and get airborne again in the time we have. The Met Office/VAAC did their job, NATS did what any ATS should have done and the operators stopped flying in the face of a known risk. There will surely be lessons to be learned and we must understand this event in detail.

It will now be interesting to see what happens should we have another ash cloud heading this way.

Despairing Traveller,

It is perhaps true that we have lessons to be learned from this event, which is by no means over in my opinion. In the history of aviation we have continually learned from our mistakes, we investigate our acccidents in detail and have developed procedures to ensure we operate as safely as we can. It is instinctive for us to stop operations when faced with risks we don't fully understand or can't avoid, such was the case in this event. And I believe most would not want it any other way. Economic pressures come second to the safety of passengers and crew- the industry and regulators have now evaluated the risk, found a way to ensure your safety- operations commence.

[Snoop]

Thanks for the link. It has been saved!

[peter we]

The CAA/NATS would I'm sure have preferred to say something along the lines of "there's ash out there guys'n'gals, check the VAAC as to where it is forecast to be, launch at your discretion", however I'll bet the operators took the view "we're only going if you say its safe to go and if it turns out it wasn't safe then we're coming after you"; the blood-sucking lawyers will have had a field day sorting out where the responsibility rests in the event of some poor sod turning their 747 into a lawn dart.

The CAA have basically said that; the risk is entirely with the operators.

If you read the Guardian article, its explains that the airlines have refused to set a safe operating level precisely becuase that exposes them to liability if things go wrong.

Why airlines resisted setting safe dust level for flights ? until now | World news | The Guardian (http://www.guardian.co.uk/world/2010/apr/21/airlines-flights-ban-airspace)

[Air.Farce.1]

Have BA or any other airline comfirmed that none of their engines have been affected by ash yet after landing in the UK last night?

Just wondering how long it takes to check? Also curious as to why there has been silence and WW has not confirmed all was ok? :confused:

[rab-k]

From The Guardian (http://www.guardian.co.uk/world/2010/apr/21/airlines-flights-ban-airspace)


Last night's reopening of the skies over the UK followed intense lobbying from an airline industry (http://www.guardian.co.uk/business/theairlineindustry) that for years has resisted efforts by regulators to set a "safe" level of volcanic ash at which it is considered that flights (http://www.guardian.co.uk/travel/flights) can continue, the Guardian can reveal.

What airlines had been afraid of was the potential damage to their reputation and finances in the event of one of their planes being lost due to dust after an all-clear had been announced, with a fear of legal actions arising from the deaths of all those who had been on board.

Unwillingness to grasp this nettle hampered what had been continuing discussions on the dust issue prior to the Eyjafjallajokull volcano erupting.

However, faced with losses running into hundreds of millions as the effect of Eyjafjallajokull spread and lingered into a sixth day, it was the airlines who began to call for the regulators to determine and set such a safe threshold, to avert the severe financial consequences of planes idle across Europe and passengers claiming refunds for cancelled journeys.
A source at the International Civil Aviation Organisation (ICAO) said of the history of the failure of efforts to agree a safe level: "The bottom line is that there is a huge liability issue for the industry here, so they have been super cautious on providing information. If they say it is safe, and there is an accident, they will get slaughtered."

The organisation has been trying since at least 2008 to get airlines and manufacturers to help establish a consensus on a safe concentration of volcanic ash.

In an indication of the pressure now put on air safety bodies, British Airways said hours before the UK's flights resumed that it hoped the UK's Civil Aviation Authority now had all the data necessary to lift the flight ban. Pointedly referring to the relaxation of restrictions by states such as Italy and the Netherlands, BA had said: "Despite the fact that airspace over most European countries is open, UK airspace remains effectively closed. We hope that on the basis of the data provided by the industry, the CAA will be in a position to direct National Air Traffic Services (Nats) to reopen UK airspace."

Airline sources said that a meeting this morning between the CAA, Nats, airline executives and the transport secretary, Lord Adonis, was "constructive" as safe flight corridors through the ash were discussed.
This week BA, easyJet and Virgin Atlantic have demanded a greater say in decisions on flight bans and air safety.

The perceived inconsistency of various European states' approaches to the volcano cloud has been one of the biggest complaints from airlines.
Ryanair, Europe's largest short-haul carrier, became the latest to reveal the scale of its losses, £5m a day, while the Emirates airline of Dubai warned of an "implosion" if restrictions were not lifted.

"Unless the states ... come in and bail these companies out, there won't be many carriers left," said Tim Clark, Emirates president. "You simply can't afford to shut down something the size of Europe."

Asked on BBC Newsnight about how much pressure the government had come under to lift the flight ban, Adonis said "They've obviously wanted to be able to fly their planes - of course they have - but that has not been the issue … the issue is the assessment of the safety authorities as to what is the safe way in which planes can fly when there is a presence of ash.

"The fact which has changed in the last week is we have had a volcanic eruption, and having to assess safe levels of ash within which planes can fly has been an urgent issue which the safety authorities have had to deal with. That's been what's changed over the last five days - it's not been pressure from the industry which has caused [it]."

The crucial change came when Nats announced that safety tests had shown aero engines "had increased tolerance levels in low ash density levels".

Nats spokesman Alex Bristol told Sky News: "We don't feel we have been under pressure from the government. Where the pressure has come has been to better understand the safety implications. Our first priority has been safety, and the reason we didn't simply lift the restrictions was because of our desire for safety."

According to the International Air Transport (http://www.guardian.co.uk/world/air-transport) Association (Iata), the crisis had cost carriers $200m (£130m) a day – most of it for European operators. A group of those airlines, including the association of budget airlines, urged the European Union to waive consumer legislation which imposes costs, including hotels for stranded passengers, during prolonged disruption; it was turning "a crisis into an economic catastrophe".

Going back into the history of attempts to set a safe level of ash, minutes of a Paris meeting in 2008 show the industry at odds with regulators. The ICAO meeting concluded that improved measurement techniques should allow progress "with regard to the definition of the lower limit on safe ash concentrations".

The ICAO complained it had "proven difficult to get formal aviation representation" at workshops on the issue organised by the UN's World Meteorological Organisation. It suggested "input of the aviation industry to this problem may have to be sought" through its sub-group on volcanoes, which has industry representatives. It asked several groups, including the International Air Transport Association, Iata, representing 230 airlines, to prepare reports for the volcano group's next meeting at Lima in Peru last month.

Minutes for that meeting show the industry did not deliver. "Iata informed the group about the strong efforts made in order to get representation from the industry ... but unfortunately these efforts had not been successful, to the disappointment of the group."

Herbert Puempel, chief of the WMO aeronautical meteorology division, who sits on the ICAO group, said the industry's reluctance was "fully understandable". "They have found it very difficult to come back with a single answer. If they have one number then it would be very low," he said. "The moment you set a limit then the lawyers will have a field day."
Iata said: "At the end of the day we are dependent on the airframe and engine manufacturers and their experts. We have encouraged them to participate." However, an aerospace industry source told the Guardian that any attempt to blame aircraft and engine makers was "passing the buck".

Perhaps I wasn't too far off the mark then...:hmm:

[Fred Bound]

Glad to be back flying, but haven't seen much discussion of this inspection requirement.

Surprised to see nothing on this in the Engs & Techs forum.

[steamchicken]

Has anyone any actual evidence of the Met Office being wrong? As in, ash turning up where it shouldn't be or no ash being where the ash was forecast?

I'm repeatedly amazed by some of the denialism on this thread, especially as people have been posting Meteosat and MODIS imagery of it since the word go. As I say, it just seems to be a sort of sub-culture of harrumphing about the Met Office (and Harriet Harman, God knows why).

[peter we]

Perhaps I wasn't too far off the mark then..

There is a legal requirement that companies assess potential risks to their business and demonstrate that they have take steps to mitigate it. Auditors will not sign off a companies accounts if there is not contingency plan in place - its to protect shareholders.

How much credibility is there in the claim that the possibility of an Icelandic volcano shutting down EU airspace was an unforeseen event?

None. It wasn't just a possibility, it was an absolute certainty to happen eventually.

[mixture]

How much credibility is there in the claim that the possibility of an Icelandic volcano shutting down EU airspace was an unforeseen event?

Given the existence of the EUR Region Volcanic Ash Contingency Plan (which uses Katla in its examples !) , what do you think the answer to that question is ? :cool:

[infrequentflyer789]

Which airline do you fly for again? I'll make a note to avoid paxing on it. I assume you also ignore the faceless bureaucrats who forecast storm cells as well, right?:ugh:

Personally, I'd rather have the pilots looking where the storm cells actually are than relying on some "forecast" from a bureaucrat. Particularly if the forecast is from a computer model at the "barbeque summer" office.

I have far more trust in those actually flying the plane than those supposedly in charge who take several days to organise a meeting to talk about maybe having a european strategy.

[ I spent 24+hrs on a coach with wife and kids - not pleasant but we got back, not the end of the world. However, I would have also taken the captains decision to fly, like we always do with every MEL etc. - most of which decisions we never even hear about sat in the back. ]

[Runway 31]

German airspace is opened for IFR flights / no more restrictions from 11:00 hrs


21/04/10 - Due to the current development of the weather situation, German airspace can be opened for flights according to instrument flight rules (IFR flights). The decision of DFS is based on the current information of the German meteorological service (DWD). According to this information, airspace contamination has significantly decreased and will continue to decrease owing to the weather conditions.

IFR flights can currently be conducted at the international airports of Hamburg, Bremen, Hannover, Berlin-Tegel, Berlin-Schönefeld, Cologne/Bonn, Frankfurt, Saarbrücken, Nürnberg, Stuttgart and Munich. The same applies to the regional airport Frankfurt-Hahn. At 11:00 hrs, all other airports will also be opened for IFR traffic. This means that from 11:00 hrs, there will be no more restrictions on IFR traffic in Germany.

Updated on: 21/4, 10:15 hrs

[iwantmyhols]

re 2166 - I will be outraged if the industry is bailed out by the tax payer. The people left unfairly out of pocket will be the traveling public who have been left to fend for themselves in all of this. The industry has turned a blind eye to this possible problem bescause it suited them to do so and now they are going to try and blame everybody else when it has back fired on them.

[infrequentflyer789]

Has anyone any actual evidence of the Met Office being wrong? As in, ash turning up where it shouldn't be or no ash being where the ash was forecast?

Increasing disagreements between model and actual sat imagery. Different affected area maps from Met Office and Eurocontrol (at least one of them has to have been wrong). More info / rumour to this effect in previous posts on this thread eg. this one: http://www.pprune.org/rumours-news/412103-ash-clouds-threaten-air-traffic-108.html#post5649483 (http://www.pprune.org/rumours-news/412103-ash-clouds-threaten-air-traffic-108.html#post5649483)

[steamchicken]

Someone was asking for mass-flow numbers earlier on. RR's Web site (http://www.rolls-royce.com/civil/products/largeaircraft/rb211_535/index.jsp) gives an intake mass-flow for the RB211-535E4B (I picked an engine arbitrarily) of 1,177lb/sec or 533.87kg/sec.

Based on the figure of 0.3 milligrams per m3 given for Stranraer, at an air density of 1.2kg/m3 at sea level (obviously we're not interested in sea level, but at least it's wrong in a known way - the ash measurement is a sea-level one and I guess RR's figures are test-stand measurements, so it's consistent) that would be 444m3 of air a second and 0.133g of ash a second - 478g of ash per engine-hour.

(Although, the -535 is a very high bypass turbofan, so perhaps we need the core mass flow...)

[Phalken]

Let the Great Experiment begin: Science will reign supreme against the detritus of more primitive gods, and tens of thousands of passengers will be as guinea pigs to prove as self-evident the safety of airline profitability and political power...

New London VAAC NWP Volcanic Ash Concentration Charts rely on so-called "standard threshold" - anyone know what this is?

According to CAA statement of 20 April: "Our way forward is based on international data and evidence from previous volcanic ash incidents, new data collected from test flights and additional analysis from manufacturers over the past few days."

Anyone know where materials of these data and analysis are located?

[STC-8]

Found this 21pg public domain document from the USGS

There's extensive detail and information as well about aircraft incidents - just some excerpts below

The 1991 Pinatubo eruptions and their effects on aircraft operations - Documents & Publications - Professional Resources - PreventionWeb.net (http://www.preventionweb.net/english/professional/publications/v.php?id=3000)


The 1991 Pinatubo Eruptions and Their Effects on Aircraft Operations
By Thomas J. Casadevall,1 Perla J. Delos Reyes,2 and David J. Schneider3
1
U.S. Geological Survey.


2
Philippine Institute of Volcanology and Seismology, Quezon City, Philippines.
3
Michigan Technological University, Department of Geological Engineering, Houghton, MI 49931.

ABSTRACT
The explosive eruptions of Mount Pinatubo in June 1991 injected enormous clouds of volcanic ash and acid gases into the stratosphere to altitudes in excess of 100,000 feet. The largest ash cloud, from the June 15 eruption, was carried by upper level winds to the west and circled the globe in 22 days. The June 15 cloud spread laterally to cover a broad equatorial band from about 10°S. to 20° N. latitude and contaminated some of the world's busiest air traffic corridors. Sixteen damaging encounters were
reported between jet aircraft and the drifting ash clouds from the June 12 and 15, 1991, eruptions. Three encounters occurred within 200 kilometers from the volcano with ash clouds less than 3 hours
old. Twelve encounters occurred over Southeast Asia at distances of 720 to 1,740 kilometers west from the volcano when the ash cloud was between 12 and 24 hours old. Encounters with the Pinatubo ash cloud caused in-flight loss of power to one engine on each of two different aircraft. A total of 10 engines were damaged and replaced, including all four engines on a single jumbo jet.

Following the 1991 eruptions, longer term damage to aircraft and engines related to volcanogenic SO2 gas has been documented including crazing of acrylic airplane windows, premature fading of polyurethane paint on jetliners, and accumulation of sulfate deposits in engines. Ash fall in the Philippines damaged aircraft on the ground and caused seven airports to close.

Restoration of airport operations presented unique challenges, which were successfully met by officials at Manila International Airport and at Cubi Point Naval Air Station, Subic Bay. Lessons
learned in these clean-up operations have broad applicability worldwide.

Between April 12 and June 9, 1991, Philippine aviation authorities issued at least eight aeronautical information notices about the preeruption restless state of Mount Pinatubo. The large number of
aircraft affected by the Pinatubo ash clouds indicates that this information either did not reach appropriate officials or that the pilots, air traffic controllers, and flight dispatchers who received this information were not sufficiently educated about the volcanic ash hazard to know what to do with the information.

INTRODUCTION
Jet aircraft are damaged when they fly through clouds containing finely fragmented rock debris and acid gases produced by explosive volcanic eruptions (Casadevall, 1992). Clouds of volcanic ash and corrosive gases cannot be detected by weather radar currently carried aboard airplanes, and such clouds are difficult to distinguish visually from meteorological clouds. In the past 15 years, there have been more than 80 in-flight encounters between volcanic ash clouds and commercial jet aircraft.

The explosive eruptions of Mount Pinatubo volcano in the Philippines in June 1991 injected enormous clouds of volcanic ash and gases into the stratosphere to altitudes in excess of 100,000 ft. Within several days of the June eruptions, at least 16 commercial jet airplanes had been damaged by in-flight encounters with the drifting ash clouds from Pinatubo. Closer to the volcano, ash fall in the Philippines damaged about two dozen aircraft on the ground and affected seven airports. This report describes the effects of the 1991 Pinatubo eruptions on aircraft and airports, seeks to understand why so many encounters occurred, and reviews the solutions to the ash-cloud hazard reached by Philippine
authorities.

Incident number Date Time (G.m.t.)1 Location Latitude Longitude Altitude (feet) Aircraft type Comments
91-01 6/12/91 0420 170 km from volcano; 60 nautical miles from LUBANG along air route B460.
14°00' 119°30' 37,000 747-300

During a 3-min encounter with volcanic ash, crew experienced thin haze inside aircraft that smelled like a burning electrical wire. Aircraft landed safely at Manila Airport. Aircraft and engines were inspected and serviced at Manila in accordance with recommended procedures. When aircraft attempted to depart, its four engines had a strong vibration, and aircraft was grounded at Manila for detailed maintenance and replacement of all four engines.

91-02 6/12/91 uk 720 km west of volcano on route from Singapore to Tokyo.
13°50' 113°50' 37,000 747-400

No significant damage to aircraft when inspected
on ground in Tokyo.

91-03 6/12/91 1630 Approx. 1,000 km from volcano; between way points
ADPIM and 11°10' 112°10' 33,000 DC-10
series 40 Flight from Kuala Lumpur to Tokyo;

observed a discharge phenomena on windshield for 20 min. Ground inspection at
Narita revealed no LAVEN. damage. Encounters 3 and 11 involved same aircraft.

91-04 6/15/91 1740 Approx. 1,150 km from volcano; between way points
SUKAR and CAVOI. 13°10' 110°50' 29,000 747-400

Aircraft encountered ash cloud at 29,000 ft at approximately 600 nm west of volcano. Crew observed St. Elmo's fire on the windshield and a scent similar to an
electrical fire in the cockpit for 6 to 8 min as they went through the ash. There was no abnormal indication in the cockpit. The crew observed a green echo, which seemed to be ash on weather radar, but it disappeared when they
were clear of the ash. Flight attendants reported thin (whitish) fog in the cabin, most dense in the upper deck compartment, followed by the forward cabin. The flight was continued to Tokyo, where engine inspection revealed that all four
engines were damaged and were replaced. First- stage nozzle guide vane cooling air holes were 70-80% blocked. Other damage occurred to the cockpit windows, cabin windows, Pitot static probes, landing light covers, navigation lights,
and all leading edge areas.

91-05 6/15/91 1547 Over Vietnam on route from Hong Kong
to Singapore; in Bangkok FIR.
13°00' 108°00' uk 747-SP
Ash and sulfur odor, electrostatic discharge, blue-green light over
Vietnam. Ground inspection revealed no significant damage, and
aircraft continued in service.


91-06 6/15/91 uk uk uk uk uk 747-200

freighter Aircraft flew through "heavy volcanic ash." Cockpit and cabin areas
were contaminated with volcanic ash. No additional information
available.

91-07 6/15/91 uk Route between Tokyo and Singapore.
uk uk 35,000 747-251

Flight from Narita to Singapore was rerouted to Manila due to weather
in Singapore area. En route to Manila, encountered volcanic ash
cloud at 35,000 ft for approximately 12 min and was then diverted to
Taipei. Engines set at cruise. Sparks were noted coming from windows
and Crew reported hearing ash hit the aircraft. EGT for all four engines rose 40-50°C and started to fluctuate. One hour later all EGTs were
back to normal. Ground inspection in Taipei revealed no significant
damage to exterior or to engines. Aircraft continued in service.

91-08 6/15/91 uk <200 km from volcano; on
approach to Manila from south.
uk uk uk DC-10
series 30

Flight from Sydney to Manila encountered ash on approach to Manila from south. Engines set at low power but found to contain "lots of ash" when inspected after landing. Exterior abrasion visible, including engine cowls.

91-09 6/15/91 uk Route between Singapore
and Osaka. uk uk uk 747-300

Aircraft was in ash cloud for 29 min while en route from Singapore to Osaka. Date of encounter uncertain, probably 6/15; one report indicates 6/19.
Inspection of aircraft exterior showed no significant damage.
Engines #1 and #4 were replaced; "90% of the first-stage turbine blades
have bullseyes on the airfoil's mid-span pressure side and some first-stage vane leading edge ash buildup at 3 o'clock position."

91-11 6/15/91 1730 Approx. 1,050
km from 15°15' 110°30' 29,000 DC-10 series 40

Flight from Kuala Lumpur to Tokyo; volcano; between way points SUKAR
and CAVOI, 120 nautical miles from CAVOI. observed a discharge
phenomena on windshield for 25 min. Ground inspection at Narita revealed no damage. Encounters 3 and 11 involved same aircraft.

91-12 6/15/91 1910 Approx. 1,050
km from volcano; between way points SUKAR and CAVOI,
120 nautical miles from CAVOI.
15°15' 110°30' 29,000 DC-10
series 40

Flight from Singapore to Osaka; crew
observed a discharge phenomena on
windshield for 30 min. Ground inspection at
Narita revealed no damage.

91-13 6/15/91 0910 Approx. 100
km from volcano; flight from Manila to
Hong Kong. uk uk uk 747-428

After takeoff from Manila, airplane skirted a volcanic ash cloud.
On the ground in Hong Kong, black marks were noted on the exterior of the left wing. Engines were borescoped and no discrepancies were found. Airplane continued to Delhi. Preparing to leave Delhi, unable to start engine #1. Fuel pump was replaced and additional inspections of airplane revealed no damage. Airplane continued to Paris.


91-14 6/16/91 uk Route between Kuala Lumpur and Kota Kinabalu.
uk uk uk 737-200

freighter Indications that aircraft flew through volcanic ash cloud were apparent only after aircraft underwent ground inspection in Kuala Lumpur, which revealed abrasion of plexiglass landing light covers and navigation lights, which were totally opaque. Cowling intakes were abraded and rough to the touch, while compressor blades were remarkably clean. Landing gear
bays were covered in ash with ash sticking to oily surfaces. No apparent damage to windshields.

91-15 6/17/91
(?) uk Flight likely on Tokyo to
Singapore uk uk uk DC-10

Airplane reportedly encountered ash from
Pinatubo on June 17. #3 route. engine was reported to have been shut down in flight; ash encounter may have caused in- flight shutdown. Inspection of engines revealed "heavy deposits" of what was presumed to be volcanic ash. No information about flight route, encounter duration, and such.

91-16 6/17/91 0412 930 km from volcano; 50 nautical miles
east of way point IDOSI on route A901.
19°30' 112°40' 37,000 747-200B

Flight from Johannesburg to Taipei via Mauritius.
Encounter occurred at 37,000 ft 50 nm east of way point IDOSI on
route A901; entered a cloud at 0412 G.m.t.; temperature increased
from -48°C to -37°C in 2 min; aircraft descended to 29,000 ft and landed at 0540 G.m.t.; engine #1 surged and was shut down; engine #4 lost power; descended to 29,000 ft to restart #1. Aircraft landed safely at Taipei. Service
terminated. Engine #1 replaced and aircraft returned to South Africa on 6/21 for further inspection.


91-17 6/15/91 na Aircraft on ground at
Manila International Airport. 14°30' 121°00'

On ground L-1011 Maintenance crew attempted to remove
volcanic ash from window by using wiper blades. Resulted in abrasion of windows, which required replacement.




DAMAGE
When a jetliner flying in excess of 400 knots (740 km/h) enters a cloud of finely fragmented rock particles, the principal damage will be abrasion of the exterior, forward-facing surfaces and
accumulation of ash into surface openings (Casadevall, 1992). An example of the exterior damage to one jumbo jet after an encounter with a Pinatubo ash cloud is shown schematically in figure 7. Ingestion of ash into the engines will cause abrasion damage, especially to compressor fan blades. Because jet engines operate at temperatures in excess of 700°C, melting of ash and accumulation of this ash in the turbine section is an important problem as well (Przedpelski and Casadevall, 1994).
Remelted ash may block the passage of air through the engines and cause the engine to stop. In an least
one airplane (incident 91-04 in table 1), first-stage nozzle guide vane cooling holes were 70 to 80 percent blocked.
Figure 7. Damage to exterior surfaces of a 747-400 jumbo jet following an encounter with the June 15,
1991, ash cloud from Mount Pinatubo.

The majority of the Pinatubo encounters occurred at distances of up to 2,000 km from the volcano with an ash cloud that was at least 12 h old. The aging of the ash cloud allowed the coarser ash to settle from the cloud and prevented some of the more severe damage such as that which occurred to jumbo-
jet aircraft from earlier encounters with volcanic ash (Smith, 1983; Tootell, 1985; and Casadevall,
1994). In the Pinatubo case, there were few reports of abrasion of forward-facing cabin windows, so it is suggested that particles larger than about 30 m in diameter had already settled from the cloud. Particles smaller than this diameter are efficiently swept over the window surface by the slipstream and do not impact the window surface (Pieri and Oeding, 1991).

Longer term damage related primarily to the SO2 gas and sulfuric acid aerosols produced by the eruption (Self and others, this volume) did not become apparent until months after the eruption. Some Asian-based carriers noted that jet engines on their airplanes have accumulated deposits of sulfate minerals such as anhydrite and gypsum in the turbine. This material blocked cooling holes in the first- stage nozzle guide vane at the inlet to the turbine section of the engine and thereby interfered with the cooling of the turbine. As a result, engines overheated. The sulfate deposits found in the turbine section appear to be related to ingestion and oxidation of SO2 and sulfuric acid aerosols that originated
in the Pinatubo eruption clouds of June 15 (Casadevall and Rye, 1994).

Additional problems related to the acidic aerosols include the increased incidence of crazing of acrylic windows (Berner, 1993) and fading of polyurethane paint on jetliners (T.M. Murray, Boeing, written commun., 1993). Unlike the circumstances involving in-flight encounters with the ash clouds, which
were largely restricted to the region west of the volcano, the gas cloud from Pinatubo has been widely dispersed throughout the Northern Hemisphere and has thereby affected aircraft that fly in this airspace. A similar increase in the incidence of window crazing was observed for several years following the
eruptions of El Chichón Volcano in 1982 (Rogers, 1984; 1985; Bernard and Rose, 1990). Pinatubo erupted nearly 3 times more SO2 than did El Chichón (Bluth and others, 1992). Thus, the types of problems related to volcanogenic sulfur gas and sulfuric acid aerosols may be expected to persist longer following the Pinatubo activity than after El Chichón.


LONG-TERM DAMAGE
In addition to the aircraft damage that was immediately evident in the days following the June 15 eruption, damage related primarily to SO2 gas has been reported by some airline companies and
manufacturers. One year after the eruption, in June 1992, there was an incident involving loss of engine power on a jumbo jet owing to accumulation of sulfate deposits in jet engines. Isotopic studies of these deposits suggest that the sulfate is derived from the ingestion and oxidation of SO2 and
sulfuric acid aerosols that originated in the Pinatubo eruption cloud of June 15 (Casadevall and Rye, 1994). Related problems recognized in 1992 such as the increased incidence of crazing of acrylic windows (Berner, 1993) and fading of polyurethane paint on jetliners are also due to volcanogenic sulfuric acid droplets in the atmosphere. Frequent inspections of aircraft should reveal any corrosion problems due to volcanogenic sulfur gases.

[VinRouge]

Willie Walsh's boardroom? :E

[cuthere]

Infrequent. You're a satellite interpretation/atmospheric dispersion expert now are you? And what does volcanic ash look like on a satellite image? Excellent. Then no doubt you know the Eurocontrol charts are based on data provided by the Met Office. (Under ICAO the MO are the ONLY body allowed to produce VAAC charts….but no doubt you knew that).

[Phalken]

Further:
"In addition, the CAA’s Revised Airspace Guidance requires 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."

Anyone has info on these?
Specs, instructions, instrumentation for inspections...?
Location of reports or CAA reporting scheme...?

[iwantmyhols]

how can these SOPs be up and running already so that all these flights were able to go- I do not understand this, it takes the company I work for weeks/months to get a gobal one of these signed off!!! These companies have got them in place in one night shift! How can their maintance teams been able to buy into/ contribute to these as some of it will depend on them?

[30AB-JK]

Initially, the God given Mk 1 Eyeball - like we have been using for years!!!

Mind you, It might have to be Licensed for Volcanic Ash Inspections :ugh:

[kyloe]

Anyone care to comment as to why this, frankly quite interesting and useful page appeared and then rather quickly disappeared from the VAAC website?

Met Office: Icelandic volcano - Ash concentration charts (http://metoffice.com/corporate/pressoffice/2010/volcano/ashconcentration/)

[Phalken]

As any coal-miner will tell you: silicosis is diagnosed only after your lungs are bleeding, when you have already begun to cough and splutter, and loose your breath until your legs give way...

[Air.Farce.1]

put in place an intensive maintenance ash damage inspection before and after each flight

So how long does this take?

[Pace]

Met Office: Icelandic volcano eruption (http://www.metoffice.gov.uk/corporate/pressoffice/2010/volcano.html)

Read into their response what you will

[handsfree]

One would imagine longer than a 30 minute turnaround allows.

[peter we]

Someone was asking for mass-flow numbers earlier on. RR's Web site gives an intake mass-flow for the RB211-535E4B (I picked an engine arbitrarily) of 1,177lb/sec or 533.87kg/sec.

Based on the figure of 0.3 milligrams per m3 given for Stranraer, at an air density of 1.2kg/m3 at sea level (obviously we're not interested in sea level, but at least it's wrong in a known way - the ash measurement is a sea-level one and I guess RR's figures are test-stand measurements, so it's consistent) that would be 444m3 of air a second and 0.133g of ash a second - 478g of ash per engine-hour.

(Although, the -535 is a very high bypass turbofan, so perhaps we need the core mass flow...)

Now, scientists and engineers have agreed a threshold concentration for ash of 0.002g per cubic metre of air. At or below this concentration, there is no damage to the engine.

BBC News - Was the flight ban necessary? (http://news.bbc.co.uk/2/hi/science/nature/8634276.stm)

Thats a pretty high level.

[Less Hair]

Germany is back to unrestricted air traffic since noontime today. IFR anywhere possible again in Deutschland.

German language source based on DFS statement:
DFS: Deutscher Luftraum wieder uneingeschränkt nutzbar - FLUG REVUE (http://www.flugrevue.de/de/zivilluftfahrt/airlines-flugbetrieb/dfs-deutscher-luftraum-wieder-uneingeschraenkt-nutzbar.21583.htm)

[Phalken]

Quote:
Now, scientists and engineers have agreed a threshold concentration for ash of 0.002g per cubic metre of air. At or below this concentration, there is no damage to the engine.

But this is a TV news report. How are measures taken?

What time scaling: 15 min? hourly? 8 or 24 hours? ...like terrestrial air pollution?

Where are the specs?

"Considering that a commercial aircraft will travel about 150 km (80 M) in 10 minutes and that volcanic ash can rise to flight levels commonly used by turbine-engine aeroplanes in half that time, timely response to reports of volcanic ash is essential."

from ICAO EUR/NAT OFFICE (Paris): Volcanic Ash Contingency Plan EUR Region (Second Edition September 2009) Page 3

[Gualala]

My take is ICAO have been trying to tackle this issue for years on 2 fronts - (1) where is ash and provide warning for it (VAAC) and (2) what is the engine susceptibility level.

They got nowhere on (2) and then set a susceptibility threshold of 0 which the CAA, and NATS adopted to the letter. One particle in the whole airspace means close it!

It seems one of the culprits for this fiasco over the years is the engine manufacturers not supporting efforts on volcanos - plus the head of ICAO, CAA and BA not persuading them to. I don't understand how in PPRUNE and the wider press, RR et al have so far got away scott free.

[Pace]

"Considering that a commercial aircraft will travel about 150 km (80 M) in 10 minutes and that volcanic ash can rise to flight levels commonly used by turbine-engine aeroplanes in half that time, timely response to reports of volcanic ash is essential."

6000 fpm? maybe from the centre of the volcanic eruption but who will be flying over that?

If not that from what level are they talking about and where......
all this scientific detail is amazing. :ugh:

Pace

[Flightmech]

Per the AMM chapter 5 it will be progressive. Initial inpsection includes evidence of windshield crazing, paint erosion, erosion of pitot tubes, TAT probes, AOA sensors, engine inlets etc, smells in air conditioning etc If findings found during this process then you move on to engine boroscopes etc etc. each manufacturer's AMM will be different but thats a very basic explanation.

[Bristolhighflyer]

Re: Airvanman's post:

"Thomas Cook TCX952P registration G-JMCF (Boeing 757-28A) just made a u-turn to Manchester, it was out over the North Sea off Nofolk/Suffolk, it reported to London and Manchester Control it had an engine bleed problem after an 'intense smell of volcanic ash in the cabin during the climb between FL160 and FL200."

FYI here is a partial transcript of what went on:

"For information we got the smell of the ash from about 16,000 feet in the climb, it stayed with us even when we were well above FL200. We had no smell at all on the way down and we're passing 14..."

ATC: "so between 160 to 200?"

"Difficult to say when it stopped in the climb because we still have the smell in here, and it took a while to clear. There are still traces of the smell but it was quite intense in the climb..."

(Later)

"Negative emergency, no special handling, everything is normal, its just that we have lost one of our engine bleeds, possibly through a contaminated valve."

Comments please?

[pete999]

People have been assigning some blame to the engine manufacturers. On here certainly if not in the mainstream media.

As a side note, this is an interesting article covering possible future directions for the manufacturers:
The Great Debate UK Debate Archive Impact of the volcano disruption on the airlines | The Great Debate | (http://blogs.reuters.com/great-debate-uk/2010/04/20/impact-of-the-volcano-disruption-on-the-airline-industry/)

[Phalken]

The simple fact is that a 20+ year-old, worldwide safety regime was overthrown at a 2 hour meeting packed with British politicians and airline executives.

[STC-8]

Long time 'lurker' - felt compelled to chime in..

Hello to all... I'm not a pilot, aircraft engineer or vulcanologist.

orig. post didn't turn up for some reason so here goes again:

Thoughts go out to stranded travelers and those impacted by the current ash situation.

The dynamics of the debate and the political, business and management pressures on the one hand versus the aircraft engine designers on the other (saying 0 tolerance for ash) is reminiscent to me of events surrounding the Challenger Space Shuttle disaster. I think there are some lessons to be considered there.


Space Shuttle Challenger disaster - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster)

Use as case study

The Challenger accident has frequently been used as a case study in the study of subjects such as engineering safety, the ethics of whistle-blowing (http://en.wikipedia.org/wiki/Whistle-blowing), communications, group decision-making, and the dangers of groupthink (http://en.wikipedia.org/wiki/Groupthink). It is part of the required readings for engineers seeking a professional license in Canada[52] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-51) and other countries. Roger Boisjoly (http://en.wikipedia.org/wiki/Roger_Boisjoly), the engineer who had warned about the effect of cold weather on the O-rings, left his job at Morton Thiokol and became a speaker on workplace ethics.[53] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-52) He argues that the caucus (http://en.wikipedia.org/wiki/Caucus) called by Morton Thiokol managers, which resulted in a recommendation to launch, "constituted the unethical decision-making forum resulting from intense customer intimidation."[54] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-53) For his honesty and integrity leading up to and directly following the shuttle disaster, Roger Boisjoly was awarded the Prize for Scientific Freedom and Responsibility from the American Association for the Advancement of Science. Many colleges and universities have also used the accident in classes on the ethics of engineering (http://en.wikipedia.org/wiki/Engineering_ethics).[55] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-54)[56] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-55)
Information designer Edward Tufte (http://en.wikipedia.org/wiki/Edward_Tufte) has used the Challenger accident as an example of the problems that can occur from the lack of clarity in the presentation of information. He argues that if Morton Thiokol (http://en.wikipedia.org/wiki/Morton_Thiokol) engineers had more clearly presented the data that they had on the relationship between low temperatures and burn-through in the solid rocket booster joints, they might have succeeded in persuading NASA managers to cancel the launch.[57] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-56) Tufte has also argued that poor presentation of information may have affected NASA decisions during the last flight of Columbia.

The Presidential Commission on the Space Shuttle Challenger Accident, also known as the Rogers Commission (http://en.wikipedia.org/wiki/Rogers_Commission) (after its chairman), was formed to investigate the disaster. The commission members were Chairman William P. Rogers (http://en.wikipedia.org/wiki/William_P._Rogers), Vice Chairman Neil Armstrong (http://en.wikipedia.org/wiki/Neil_Armstrong), David Acheson, Eugene Covert, Richard Feynman (http://en.wikipedia.org/wiki/Richard_Feynman), Robert Hotz, Donald Kutyna (http://en.wikipedia.org/wiki/Donald_Kutyna), Sally Ride (http://en.wikipedia.org/wiki/Sally_Ride), Robert Rummel, Joseph Sutter, Arthur Walker, Albert Wheelon, and Chuck Yeager (http://en.wikipedia.org/wiki/Chuck_Yeager). The commission worked for several months and published a report of its findings. It found that the Challenger accident was caused by a failure in the O-rings sealing a joint on the right solid rocket booster, which allowed pressurized hot gases and eventually flame to "blow by" the O-ring and make contact with the adjacent external tank (http://en.wikipedia.org/wiki/Space_Shuttle_external_tank), causing structural failure. The failure of the O-rings was attributed to a faulty design, whose performance could be too easily compromised by factors including the low temperature on the day of launch.[34] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-33)
More broadly, the report also considered the contributing causes of the accident. Most salient was the failure of both NASA and Morton Thiokol to respond adequately to the danger posed by the deficient joint design. However, rather than redesigning the joint, they came to define the problem as an acceptable flight risk. The report found that managers at Marshall had known about the flawed design since 1977, but never discussed the problem outside their reporting channels with Thiokol--a flagrant violation of NASA regulations. Even when it became more apparent how serious the flaw was, no one at Marshall considered grounding the shuttles until a fix could be implemented. On the contrary, Marshall managers went as far as to issue and waive six launch constraints related to the O-rings.[35] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-34) The report also strongly criticized the decision making process that led to the launch of Challenger, saying that it was seriously flawed.[36] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-35)
“ ...failures in communication... resulted in a decision to launch 51-L based on incomplete and sometimes misleading information, a conflict between engineering data and management judgments, and a NASA management structure that permitted internal flight safety problems to bypass key Shuttle managers.[37] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-36) ” One of the commission's most well-known members was theoretical physicist Richard Feynman (http://en.wikipedia.org/wiki/Richard_Feynman). During a televised hearing, he famously demonstrated how the O-rings became less resilient and subject to seal failures at ice-cold temperatures by immersing a sample of the material in a glass of ice water. He was so critical of flaws in NASA's "safety culture" that he threatened to remove his name from the report unless it included his personal observations on the reliability of the shuttle, which appeared as Appendix F.[38] (http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#cite_note-37) In the appendix, he argued that the estimates of reliability offered by NASA management were wildly unrealistic, differing as much as a thousandfold from the estimates of working engineers. "For a successful technology," he concluded, "reality must take precedence over public relations, for nature cannot be fooled.

[eagleflyer]

This was the biggest farce in our company´s history! I completetly lost faith in our management and political leadership in the last couple of days.

No one seems to have the slightest understanding of what safety in aviation means. Stick to known procedures for example, or at least brief unusual procedures thoroughly. How on earth can someone in his right mind consider it safe if a passenger jet goes VFR through airspace E at 1200ft AGL 20 miles away from the field trying to find his way towards the runway while trying to seperate itself from small Cessnas and to establish a sequence to other big jets doing the same??

[nnc0]

So how long does this take? (put in place an intensive maintenance ash damage inspection before and after each flight)



Paraphrasing from a knowledgeable fella on another board

Assuming engine has cooled down a bit and there are no hiccups in doing the job
5 minutes to get the cowls opened,
3 minutes to get the boroscope plugs out,
5 minutes to get access to turn the N2 rotor through the gearbox,
10 to 30 minutes for inspection
X mins to send pics for analysis if there's an obvious issue/concern
30 -60 minutes to get the plugs back in and locked,
5 or ten to get the N2 drive pad access cover back on
Y minutes for a leak check (possible engine run rqd)
5 minutes to close the the cowls

Total time required = 63 + X + Y minutes
(varies per engine type)

Summary - you could expect an average of somewhere between 75 - 90 minutes

[pete999]

It's true but something had to be done, otherwise the situation would have gone on forever. And it wasn't just the UK - exactly the same thing obviously happened the previous day when Eurocontrol's ash map magically changed after pressure from the EU.

It's been quoted several times on here already, but I think it's important to bear in mind the warning that the ICAO themselves made about their own policy back in 2008:
"As remote sensing techniques improve, it is likely that the aggregate areas
where ash is sensed or inferred will increase, possibly leading to over-warning for ash and cost-blowouts for airlines."

[markhooper]

The simple fact is that a 20+ year-old, worldwide safety regime was overthrown at a 2 hour meeting packed with British politicians and airline executives.

No, I think they just reinstated it. ie. "See and avoid"

[peter we]

But this is a TV news report. How are measures taken?

What time scaling: 15 min? hourly? 8 or 24 hours? ...like terrestrial air pollution?

Where are the specs?


There will be very few measurements, it will be based on the Met Office predictions which will now be taken as Gospel as they allow flights to precede.

The Met office provided the wrong answer, so the question has been changed.

[Profit Max]

According to news reports from Germany, it was the "right kind of ash" after all. It appears that the Eyjafjallajökull ash consists of basalt, which only melts at 1,200°C, a temperature in the engines normally only reached during take-off. The ash of many other volcanoes (including Pinatubo, Mount St. Helens or volcanoes in the Andes) consists of andesite, which melts at below 1,000°C, a temperature in the engines reached much more frequently.

The abrasive properties of basalt appear to be the same as those of andesite though.

Ergebnisse des Messflugs: Vulkanasche schwebt in 3,5 bis 6 Kilometer Höhe - SPIEGEL ONLINE - Nachrichten - Wissenschaft (http://www.spiegel.de/wissenschaft/natur/0,1518,690205,00.html)

[Beanbag]

Just curious to know what the pax on those 10 flights were told. That they were going to be guinea pigs on a test of the aircraft's response to ash? That diversions were likely if WW's bluff was called?

I wonder if anyone declined to travel on that basis.

[albi]

Saw the headlines of the Comic The Daily Star which shows photo of a 747s engines all on fire as it flies through the volcanic ash cloud...... what it doesnt tell you is its a still from Air Crash Investigation off sky relating to the BA flight in the 80s c/o cpt Moody...... if thats not arse end scare mongering from journalists who should actually be washing the salad at Mcdonalds instead of scaring the general public... i dont know what is, the airlines have had enough of a battering from this and the downturn without them making s@*t like this up.... they should be hung drawn quartered and dipped in battery acid for a week and then forced to watch their relatives on Jeremy Kyle.... is that a bit harsh... rant over:}

[Fred Bound]

Just curious to know what the pax on those 10 flights were told.


Probably that they would be landing at Heathrow.

LHR was previously forecast to be open by 19.00BST as part of the phased opening starting at 07.00 in the north. Notice that the BA flights started to arrive in time for that 19.00 opening - BA124 being the first to show up crossing the Dutch coast at about 18.45.

By the time it was announced that the planned re-opening wasn't going to happen, all BA's were en-route.

Who can blame them for continuing hoping for things to change.

[pete999]

According to the Guardian, they had to remove these newspapers from shops in Gatwick and Manchester airports to avoid panicked passengers.

Pretty irresponsible stuff from the editor.

[seat 13a]

Pax inbound on BA longhaul last night asked to sign a waiver, I understand, saying that they understood they might be diverted away from LHR...

[STC-8]

Similarities between the leadup to the Challenger disaster & the current flying through ash situation I think lie in the element of powerful political, management, public & economic forces wanting to get 'the bird in the air' versus the quiet voice of those involved with the engineering side saying its not wise.

In the case of the shuttle, engineers were warning 'do not launch, safety cannot be guaranteed under these conditions' yet the concerns were ignored. In this current ash debate, powerful voices from the airline industry and politics monopolize the discussion, particularily in the media - whereas those who have expert, detailled knowledge of airplane engines and ash, namely the engineers who design and manufacture jet engines, are less heard (their message: ' ash & jet engines don't mix'). Yet, it appears the public & those in authority to make decisions are hardly hearing the voice of the true experts on the subject during this crisis.

Uncharted territory...

I'm hoping that existing protocols, wind, luck & maintenance regimes will help avoid any potential catastrophic outcomes. Just imagine what an ash-related accident would do to the industry (!)...

[Phalken]

It's true but something had to be done, otherwise the situation would have gone on forever.

The point is: Where is the science? Before or after this decision?

[BarbiesBoyfriend]

Lord Adonis stated on 'The world at One' today that there had been an over reaction to the Ash event by the authorities concerned.

Fancy that.

I'm no expert, but it seems me that only an idiot would knowingly fly into the plume found above a volcano.

However, low levels (too low to see at all from air or ground) must have been encountered countless times over the years with no one any the wiser, and no problems reported, given that there are plenty active volcanoes all over the world.

Given that any problems to be caused by ash from Iceland are plainly going to be tiny compared to flying in the plume, why not simply fly on and see if any problems occur- likely none will.

I guess we are now in that situation.:rolleyes:

Definately, as many on here have said and now had confirmed by the gummint no less, a gross over reaction.

[BoughtTheFarm]

Whilst there will be diverse opinions about the events of last night, the fact remains that BA had a number of Speedbirds inbound to LHR and LGW and whatever was going on in COBRA, with some still in holds long after they could have diverted a decision was made to act. Note - DECISION. Whilst it's easy from the armchair to "fly the plan" sometimes someone needs to step up and take a tough decision.

If WW did indeed bring pressure to bear to get UK FIR's open then I stand by him. After some days of little clear directive other than what some could describe as health and safety syndrome, the fact is that UK airspace cannot be closed for business indefintely without someone or body standing up to be counted. If WW did that then good on him.

Safety first yes. But, it takes more courage to stand up and make the call than be part of a group erring on caution no matter what.

BA got the planes in. The skies are open and I hope lessons are learned from this so that mother nature cannot be the only one deciding on how we go about our lives.

Whatever the context and final outcome, good job to the crews who brought their birds in. Not everyone may agree that BA is still the 'worlds favourite airline' but I for one would say that they are the 'worlds most determined airline'. We sometimes need people to take tough decisions, and I for one prefer a world with them than without.

[ex-EGLL]

Well this is a rumour network, so here goes.

Flew into YYZ from FRA yesterday on LH. Talking to some of the AC staff in YYZ, it seems that LH operated the same flight, A340-600, a day earlier albeit at a later departure time. During the turn round inspection "ash damage" was found in the engines. Aeroplane towed to maintenance area.

Any one able to confirm / deny this.

I must admit that I was alittle suprised at out routing yesterday, FRA- London - South Wales, to 55N for the crossing, I was expecting to be further South.

We were told that the highest reported ash had been FL350, so we went at FL360!!:hmm:

ex-egll

[Phalken]

Lord Adonis stated on 'The world at One' today that there had been an over reaction to the Ash event by the authorities concerned.

Reaction was based on long-standing international safety proceedures, and especially on manufacturers' (both engine and body) zero-tolerance of volcanic ash. They have (apparantly) revised this tolerance upward by 10x, but as any child knows 10x0=0!

It begs the question: why did Adonis not make this change before? But we know from this morning's Guardian that airlines have opposed revision for their own legal/economic advantage.

[yoganmahew]

Mr. O'Leary was on RTE news saying that he thought it was fair enough that airspace was closed for a day or two last week while assessments were made of whether it was safe to fly on not. He did not think it justified that it has taken seven days to come to a conclusion on that.

It does not take huge bravery to close airspace, but having closed it, it takes huge bravery to reopen it.

[John Farley]

Understanding why a jet engine should flame out when heavy concentrations of ash go in the front end (compressor and combustion chambers) is just common sense. We also know from experience of this that it is possible to glide down for 15 mins into some cleaner air where the engines can be restarted.

However, there is another failure mode which is much more of a problem and potentially terminal for the engine.

If very fine material that the compressor and combustion stages can happily swallow enters the engine, the risk is to the turbine which in normal operation must be cooled. This risk arises because the airflow past the turbine is sometimes several hundred degrees above the melting point of the turbine material. The cooling air exits through a myriad of small holes in the surface of the blade ensuring that the blades are encased in a cocoon of cool air.

Clearly quite small particles could affect this cooling flow but even worse, depending on the composition of the particles, the temperature can cause some of the particles to change their nature and form a glass like material that can build up in and on the blades. In the worst case such a process, when the engine is running normally, could destroy the turbine in a minute or so.

Apologies to all those who understand these matters.

[fleigle]

Time to buy stock in engine manufacturers/re-builders methinks.:E

[Fred Bound]

BBC News (http://redirectingat.com/?id=42X487496&url=http%3A%2F%2Fnews.bbc.co.uk%2F1%2Fhi%2Fscotland%2Fnorth_ east%2F8634712.stm&sref=http%3A%2F%2Fwww.pprune.org%2Frotorheads%2F412150-helicopters-volcanic-ash-12.html)

Offshore Helicopter Operations

[anotherthing]

Lord Adonis stated on 'The world at One' today that there had been an over reaction to the Ash event by the authorities concerned.
Lord Adonis would be best advised to keep his mouth shut and seek some advice before spouting of.

Irrespective of whatever anyone on here thinks about the decision to close airspace in the UK, the glaringly obvious FACT during the whole episode is that none of the incumbent Cabinet Party were visible in the first few days. They only started coming out with opinions when it was clear that the airspace was about to re-open - and even then they didn't know the roles of NATS etc.

Looking at charts over the past 24Hrs, even if using the old criteria the majority of UK airspace would now be open.

It's very easy for politicians to say it was an over-reaction - pity they didn't have the balls to stand up at the outset...

HMG acted very poorly (well, very seldom) throughout this whole episode :=

[infrequentflyer789]

BBC News (http://redirectingat.com/?id=42X487496&url=http%3A%2F%2Fnews.bbc.co.uk%2F1%2Fhi%2Fscotland%2Fnorth_ east%2F8634712.stm&sref=http%3A%2F%2Fwww.pprune.org%2Frotorheads%2F412150-helicopters-volcanic-ash-12.html)

Offshore Helicopter Operations

With interesting line being: "There was no damage and no ash was found in engines."

Another interesting snippet from bbc ( BBC News - Volcano cloud as it happens: 21 April (http://news.bbc.co.uk/1/hi/world/europe/8634046.stm) ):

Dr Colin Brown of the Institute of Mechanical Engineers in London has studied the effect of volcanic ash on plane engines. He told BBC World Service: "We've been running test flights over the last four or five days and collecting information from the engines that have flown through those clouds and seen what damage the clouds done to them, and we've found that the damage is zero and so we're in the situation where we're now happy to continue flying through those clouds."

[rab-k]

BoughtTheFarm

Whatever the context and final outcome, good job to the crews who brought their birds in. Not everyone may agree that BA is still the 'worlds favourite airline' but I for one would say that they are the 'worlds most determined airline'. We sometimes need people to take tough decisions, and I for one prefer a world with them than without.

A "tough decision" would have been to accept full responsibility for safe conduct of flights through contaminated airspace whatever the outcome. BA could've been flying all week long had WW simply said that he and his board of directors would do so, irrespective of CAA/Met Office advice. Guess what, they didn't.

Instead, they sat wringing their hands looking for someone else to make the decision and when that didn't come quick enough they turned up the heat on, in this case, our 'unelected' politicians.

Nothing brave about wanting to carry on doing something whilst at the same time looking to apportion blame elsewhere in the event of an incident.

If it turns out it is one of his 747s with a double IFSD (http://www.pprune.org/rumours-news/412863-747-emergency-diversion-two-engines-shut-down.html)I'll look forward to hearing his take on the supposed over reaction on the part of the CAA.

[Postman Plod]

Now. If that will not happen, which is far more likely, do you expect any MET Office, NATS, CAA bodies will take any responsibility? For what they've done, they should be jailed and heavily penilized (on personal level, not only as organisation) for a gross misconduct.

Why should they?! They have done EVERYTHING right and by the book, as per manufacturers reccomendations, as per ICAO guidance, and observations have backed up forecasts. Gross misconduct? I think not. Safety before money - yes.

Should the airlines have done more for their passengers? Maybe. Should the government have done more for stranded passengers of all nationalities? Yup. NATS / CAA / Eurocontrol / Met agencies have done their jobs in the face of increasing pressure and hostility from those losing money.

[infrequentflyer789]

From BBC News - Ash cloud chaos: Airlines face huge task as ban ends (http://news.bbc.co.uk/1/hi/uk/8633892.stm)

Meanwhile Ryanair has said it will defy the regulations and warned customers it will only reimburse customers their airfare and no additional expenses.Here's your 50p back, good luck hitching to Calais...

[lomapaseo]

The aviation industry, because there seems to have been so little prior investigation of the physical effects of this phenomenon. How can airframe and engine manufacturers have issued documents stating that should be no flight through ash-contaminated airspace with a straight face? Surely that was a prohibition honoured more in the breach than the observance, since a zero concentration of ash is clearly never possible, mathematically or practically, in the atmosphere of a planet whose geology is driven by plate tectonics.


Question above ..... How could XXX have issued documents ....

Be careful of using a lay persons intreprrtation of what these documents for the pilots are intended to convey.

Lets get back to the traffic light anology of red light clouds, yellow light clouds ad green light clouds.

It was postulated based on routine everyday maintenance findings that volcanic ash in clouds exists everyday someplace in the world and that some planes fly through it without impact on the flight. Thus the Green-light cloud concept.

Then there are the rash of events following a major eruption like Pinatuba where the cloud being unseen and untracked produces any symptoms described in detail in the OEM warnings that should be reacted to by the flight crews and the ground engineers This at least defines the Yellow clouds that were either not identified and tracked or that there was no intended avoidance. The OEMs thus have a duty to warn that abnormalities may occur in this situation.

And finally the Red Light cloud that represents the worst of the combinations of either not being tracked or not being avoided and at the same time producing major symptoms in combination of smell, sight, windshield effects, Pitot effects, engine symptoms and an immediate need to throttle back engine descend and turn away.

I believe that what is being dealt with today is the realization that all clouds are not bad and that traffic control and alert pilots can still lead to safe flights.

[H.Finn]

Here we go: Finnish AF has now inspected the engines of the F-18 Hornet, which were allegedly damaged in flying into the volcanic ash. You know, the ones of which fine pictures were shown on tabloids and even reputable papers.
Finding: NO DAMAGE FOUND!!!! Ok, traces of ash, but: NO DAMAGE!!!!

Why am I not surprised....

[silverstrata]

Steamchick:
Unfortunately, it just seems that there is a sort of subculture of (usually) right-wing people in the UK who are obsessed with the idea that the Met Office is plotting against them. This thread has now reached the point where the same people who were yelling that Gordon Brown was at fault for closing the airspace and it wasn't really a problem - no link or citation has yet been produced to support the idea that it was Brown's decision rather than CAA, NATS, or VAAC - are now yelling that Brown should really intervene and have it reopened rather than "hiding behind NATS".


No, there is a body of normal, rational people of many political persuasions who want to know who made the decision to close all airspace. It is a reasonable question to ask. And in the absence of any hands going up, it is natural to go to the top and ask what role the government played in all this.

And even if the government was not directly involved, they have still instituted and encouraged the recent social atmosphere where no risk-taking is allowed - which precipitated the closure of airspace in the first place. Had this been the 1950s (even with jets, satellites and computers etc,), we would have carried on flying, as you well know.


And BTW, I have flown for two days across all Europe, and not seen a speck of vitrious deposits on my turbines. Ergo, at whatever concentrations we have now, everything is fine. Are you listening, CAA, NATS, Eurocontrol and governments??



Oh, and as an aside, why were all those who were against the closure of airspace deleted from this site? Especially as we turned out to be correct, and the closure was excessive. If that is not political/judgmental, I don't know what is.


.

[anotherthing]

Yup. NATS / CAA / Eurocontrol / Met agencies have done their jobs in the face of increasing pressure and hostility from those losing money.
Some people tend to forget the fact that during this NATS has been losing heaps of money as well. Not the sums the larger airlines have, because NATS profit is miniscule to the likes of BA. Taken as a percentage of earnings though, NATS have lost as much profit as any other organisation - not far from a months worth of profit down the drain.

[Airbubba]

Be careful of using a lay persons intrepretation of what these documents for the pilots are intended to convey.


And, the way these things are written, often pilots can't figure out what they are trying to say. The human interface on our NOTAMs and other flight papers is primitive to say the least. Obscure abbreviations and lack of graphics with coded number and letter groups mean it's so easy to overlook something important. Everything is in caps since 1930's teletypes couldn't do lower case.

[WHBM]

Lord Adonis stated on 'The world at One' today that there had been an over reaction to the Ash event by the authorities concerned.
We will therefore be standing by for Lord Adonis' resignation. He is at the top of the whole tree of bureaucrats.
If WW did indeed bring pressure to bear to get UK FIR's open then I stand by him. After some days of little clear directive other than what some could describe as health and safety syndrome, the fact is that UK airspace cannot be closed for business indefintely without someone or body standing up to be counted. If WW did that then good on him.
Indeed. Well done WW for actually pushing it through and launching all those flights from overseas (was it really 26 ?) into London to arrive the minute it was planned to open. I may have had harsh words about his commercial and managerial decisions in the past, but am right behind him on this one. Bear in mind, all those going on about the commercial aspects, the principal beneficiaries of this were the PASSENGERS who were returned home. Sometimes they get forgotten along the way.

Notably the Bearded Wonder didn't do the same at his carrier.

[blueskythinking]

whilst I agree completely that lessons need to be learnt from this whole incident. I am not sure I have seen it stated anywhere that Nats as a company has also lost millions of pounds in revenue during the crisis. Nats has been portrayed as somewhat like a police service of the air. Personally if I had been in charge of Nats (god forbid some may say ! ) i would have said that the airspace was open and it was up to the caa , government and the airlines to make the decision to fly or not. I would put forward that Nats overstepped its remit and to listen to junior people being allowed to appear on TV and advise passengers what to do or not do was a total farce. I have not seen the new ceo at any time on tv or senior board members! I think the airlines were well placed to make their own judgements , obviously with government and met office guidance. If , as seems likely it was a case of possible long term engine damage as opposed to aircraft having in flight shutdowns then That is a commercial decision for the operators.

[H.Finn]

I'll try to give a link, but it is in Finnish...

Puolustusvoimat: Ilmavoimat raportoi tuhkapölyn vaikutuksista Hornetin moottoriin (http://www.mil.fi/ilmavoimat/tiedotteet/5998.dsp)

[silverstrata]

And, the way these things are written, often pilots can't figure out what they are trying to say. The human interface on our NOTAMs and other flight papers is primitive to say the least. Obscure abbreviations and lack of graphics with coded number and letter groups mean it's so easy to overlook something important. Everything is in caps since 1930's teletypes couldn't do lower case.


Hooray, well said.

I have been asking for a map of NOTAM sites at the beginning of all NOTAMS for over 20 years. (especially for PPLs, where route NOTAMS are not always available). Yes, graphics for taxiway closures would be nice too, instead of everyone in the pilot community spending hours trying to find exactly where W1 and F6 are.

And little things like grass-cutting, bird scaring and firework displays being the top lines and waaaayy down the bottom you find that the ILS and radar are out of action.

The guys and gals who make NOTAMS should be tasked with reading all the NOTAMS within 4 minutes (all we are allowed) and if they fail, they should be put out to grass.

.

[silverstrata]

If WW did indeed bring pressure to bear to get UK FIR's open then I stand by him. After some days of little clear directive other than what some could describe as health and safety syndrome, the fact is that UK airspace cannot be closed for business indefintely without someone or body standing up to be counted. If WW did that then good on him.


And where, one might ask, was the BIG Mouth of Aviation himself during all this?? Normally willing to push every operational and safety parameter to its absolute limit, suddenly the Big Mouth of Aviation goes quiet?

Is he turning over a new leaf - or suddenly aware that safety considerations need considered discussion rather than a bullying Big Mouth?


.

[GarageYears]

Via Google translation:

Air Force studies, the ash dust did not cause significant damage to the Air Force Hornet fighter jet engine. Exposed volcanic tuhkalle fighter engine study found, however, signs of the engine surfaces accumulated contaminants.

Air Force safety switch engine parts, which show signs or foreign material implantation. Detachable parts will be carefully analyzed, and then settled their usefulness in the future.

Machine on the surface of the collected dust and engine components of the samples have not yet shown results. The analysis of air samples, however, is found in volcanic material in the typical elements such as aluminum, silicon, magnesium, sulfur and iron.

Operations will continue piston engine fleet. Aviation training jet-turbine equipment, and kick start gradually.

Two Air Force Hawk jet trainer planes remain on standby Pirkkala base case letters rogatory. Both are sampling its safety yet.

Operational Operations are managed as usual.

So not quite no damage, but perhaps better characterized as limited or minimal damage.

- GY

[ricardian]

HIAL (http://www.hial.co.uk) have just (16:00) announced that all HIAL airports north of Inverness (including Wick, Kirkwall & Sumburgh) are closed due to a volcanic ash cloud. Next update will be at 18:00.

[BDiONU]

I am not sure I have seen it stated anywhere that Nats as a company has also lost millions of pounds in revenue during the crisis. .
OK, the figures are in the public domain. NATS income is circa £2.1 million per day and running costs circa £1.86 million per day, you can do the math :)
Nats has been portrayed as somewhat like a police service of the air.
Not our job.
i would have said that the airspace was open and it was up to the caa , government and the airlines to make the decision to fly or not.
Nope, NATS operates on a licence from CAA (the goverment) and as a part of the conditions of it's licence must abide by rules, regulations and laws, including the ICAO guidance etc. which the government signed up to. Every ANSP in Europe operates similarly and, as you seem to have missed it, a lot of european ANSPs closed their airspace. Indeed some countries went further and banned all flying, but HM Government didn't take that step (and NATS don't have that remit).
I would put forward that Nats overstepped its remit and to listen to junior people being allowed to appear on TV and advise passengers what to do or not do was a total farce. I have not seen the new ceo at any time on tv or senior board members!.
Hhhmm, you must have missed NewsNight when Jeremy Paxman interviewed the new CEO. All the spokesmen on the TV etc were ATC facing senior managers (Alex Bristol Head of Strategy & Investment, Jonathan Astill Head of ATC Prestwick Centre, David Harrison formerly GM ATC Manchester now Head of Safety and so on) I think a member of the board wouldn't have quite the same street cred as a senior ATC manager.
I think the airlines were well placed to make their own judgements , obviously with government and met office guidance. If , as seems likely it was a case of possible long term engine damage as opposed to aircraft having in flight shutdowns then That is a commercial decision for the operators.
No it's not a commercial decision, it's a safety decision. Pilots may only fly aircraft with a relevant air safety certificate, pilots may only fly aircraft for which they have a valid licence. This is done for many safety reasons but a big one is public safety. I wouldn't want some gung ho flyer leaping into the skies when it had been deemed potentially unsafe to do so and have the wreckage landing on my head thank you very much.

BD

[paidworker]

I am amazed at the amount of people looking for heads to roll when all those heads did was follow the rules. Nobody can say any different .. Yes you may feel that the rules were over the top and that may well be , but herd ( or CEO opinion ) in itself should never be responsible for the convenient ignoring or sidestepping/ bulldozing of those rules. Neither should a 6th form physics experiment. I am sure there was a tremendous amount of work for the engine manufacturers to do in order to change their position and explicit rules in regards to volcanic ash.

I am relieved that things seem to be settling down now as my own company has been suffered some serious economic damage in the six days and the medium term damage we are unable to quantify at this time, still though at least we can now operate again.

[Airbubba]

The guys and gals who make NOTAMS should be tasked with reading all the NOTAMS within 4 minutes (all we are allowed) and if they fail, they should be put out to grass.

Just to show what we are talking about here is an actual volcanic ash advisory from pilot departure documents:

FVCN01 CWAO 211143
VA ADVISORY
DTG: 20100421/1143Z
VAAC: MONTREAL
VOLCANO: EYJAFJOLL 1702-02
PSN: N6337 W01937
AREA: ICELAND-S
SUMMIT ELEV: 1666M
ADVISORY NR: 2010/034
INFO SOURCE:
RMK: PLEASE SEE FVXX01 EGRR 211126 ISSUED BY LONDON
VAAC WHICH DESCRIBES CONDITIONS OVER OR NEAR
THE MONTREAL VAAC AREA OF RESPONSIBILITY

Which references this message that may or may not be included in the paperwork:

Subject: FVXX01 EGRR 211126


FVXX01 EGRR 211126 2010111 1127
VA ADVISORY
DTG: 20100421/1200Z
VAAC: LONDON
VOLCANO: EYJAFJALLAJOKULL 1702-02
PSN: N6338 W01937
AREA: ICELAND
SUMMIT ELEV: 1666M
ADVISORY NR: 2010/030
INFO SOURCE: ICELAND MET OFFICE
AVIATION COLOUR CODE: RED
ERUPTION DETAILS: ERUPTION CONTINUING TO AROUND FL120 TO FL160.
OBS VA DTG: 21/1200Z
OBS VA CLD: SFC/FL200 N6345 W02025 - N6337 W01219 - N6447 W01202 -
N6432 W00635 - N6234 W00431 - N5835 W00423 - N5744 W00551 - N5744
W00914 - N5416 W00405 - N5209 W00303 - N5136 E00400 - N4944 E00249 -
N4846 W00135 - N4711 E00417 - N4623 E00351 - N4611 W00201 - N4944
W00847 - N5324 W01746 - N5345 W02644 - N5513 W03348 - N5802 W03728 -
N5831 W03941 - N5826 W04534 - N5627 W05025 - N5247 W05720 - N5018
W05746 - N4817 W05831 - N5313 W04958 - N5136 W03618 - N4605 W02551 -
N4249 W02432 - N4110 W02525 - N4143 W02728 - N4835 W03458 - N4938
W03813 - N4956 W04432 - N5029 W04534 - N5029 W05052 - N4635 W05804 [remainder of coordinates omitted for brevity - Airbubba:)]
RMK: NO SIG ASH ABOVE FL200. ASH CONCENTRATIONS UNKNOWN. ALL PLUMES
ON ALL FOUR CHARTS APPLY TO SFC TO FL200.
NXT ADVISORY: 20100421/1800Z=


You can actually figure out what it says if you guess a little - e.g. PSN must be positon since it is followed by a lat long but why are we still using decoder rings in this era of high speed internet and laser printers? A few more vowels, a little punctuation, graphics and some formatting sure would make this easier to read. I realize there are much better versions of this advisory available on web pages but often the terse teletype text is all that makes it to our paperwork. Of course, if something goes wrong, they'll have the full color graphics at the hearing.

Apologies for talking a little shop with this operational pilot stuff on the ash advisories.

[Brian McGrath]

Looks to be getting pretty active again in the past few hours, this morning it was only a very small amount of cloud around it. Third picture down

Link: Mulakot - myndavelar (http://www.mulakot.net/myndavelar.html)

[Phalken]

Officials say 90% of flights will be operating at Heathrow by 1500 today and service should be at 100% by Thursday. However, that figure includes only regularly scheduled flights, not efforts to clear up the backlog of passengers.

How can this be when the CAA's Revised Airspace Guidance last night requires 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?

[Clandestino]

perhaps better characterized as limited or minimal damage.

Depends on the viewpoint; turbine bucket with ash sticking to it does not affect engine performance much. Replacing or scrubbing it might prove costly and time consuming.

Yes I did my "test" flight, thank you for asking.

Ever helpful ATC confirmed that my penetration of VA alert area was solely upon my discretion. I would have appreciated that even more, if they choose some earlier moment to tell me that than post-landing taxiing.

No, the engines did not flameout, stall, show glowing around intakes or props, spout fire from exhausts or increased their respective ITTs erratically & rapidly. There was no st Elmo's fire visible on the screen, it was noon anyway, and no strong sulfuric odour was present.

As I have made the post-flight written confirmation of the above mentioned facts, the maintenance stated that just flying through suspected VA contaminated area does not warrant complete post VA penetration maint procedure and cleared the machine for further flights.

At least now I won't get the bill if the overhaul comes before planned time.

Regarding see and avoid: in severe CAVOK one can discern layers of dirt in the atmosphere. Now I know what I've seen yesterday over mid Italy - it looked exactly as photo on the page 3 of German Falcon flight report. There was no practical way of going around this one, it stretched from the horizon to horizon. And I can tell that regarding my routing, Met office's prediction of VA spread was frighteningly correct.

[Buckster]

are you saying they are not following the CAA guidelines ?

doesn't it say if an aircraft flies into a low ash density area that damage inspection has to occur after the flight ?

[BigAl94]

Met office report Northern Ireland 1400 BST — ash layer around 8500 ft, at least 500 ft thick - visibility greatly reduced with a strong sulphur smell.

[paidworker]

Unconfirmed: Source BBC.

BBC reporting that pax from QF32 ( Heathrow - Singapore ) are contacting them. Flight is boarded but holding pax on the ground pending an improvement in the "air quality ". The skipper is telling pax that the ash concentration is above the levels in which Qantas are happy to fly.

[Clandestino]

are you saying they are not following the CAA guidelines ?

No - we're not regulated by the UK CAA anyway and they did they homework; risk was assessed , procedures put in place after liaising with local CAA. Leading edges, props, engine intakes and transparencies were checked for abrasion damage or dust accumulation. None was found and acft was returned to service. Legal - yes, sufficient - couldn't say.

[Buckster]

Clandestino (http://www.pprune.org/members/107081-clandestino) - thanks for the clarification - makes sense.

btw I'm glad flight wasn't eventful for you.

[BoughtTheFarm]

Rab-K - Your earlier post is twaddle. BA would not have just kept flying from day 1. After 5 days on FIR closure a DECISION needed to be made. Keep up the same position or open airspace. It's far easier to close it on safety grounds than open it on the same. But at some point a decision needed to be made. If WW helped get that one way or the other then good.

Inaction and hesitation are no more the friends of safety than knee-jerk, just do-it are. After 5 days and most EU FIR's starting to operate the UK was in danger of being the 'first ones in and the last ones out'.

And anyone who thinks that commercials are not heavily in play on all of this are much mistaken. No Buck, no Buck Rogers as they used to say in Flight Test.

As I said, I'd sooner have people who step up to the plate and make a decision than keep examining their naval fluff until someone else makes the decision for them.

We didn't go to the moon by waiting for the all clear from every quarter let alone getting to and from JFK. 'Decision height'. Captain Walsh called it.

[ricardian]

HIAL (http://www.hial.co.uk/) have just (16:00) announced that all HIAL airports north of Inverness (including Wick, Kirkwall & Sumburgh) are closed due to a volcanic ash cloud. Next update will be at 18:00.
HIAL update at 19:00 - airports closed until Thursday morning.

[Diversification]

Volvo-Aero has a short piece about ash in their jet engines, see the following url:
Actual - Actual : Volvo Aero (http://www.volvoaero.com/volvoaero/global/en-gb/newsmedia/press_releases/actual/Pages/Default.aspx)
In princople they state that their engines can stand rain, ice and some birds, but not ash.

[acad_l]

Someone was asking for mass-flow numbers earlier on. RR's Web site (http://www.rolls-royce.com/civil/products/largeaircraft/rb211_535/index.jsp) gives an intake mass-flow for the RB211-535E4B (I picked an engine arbitrarily) of 1,177lb/sec or 533.87kg/sec.

Based on the figure of 0.3 milligrams per m3 given for Stranraer, at an air density of 1.2kg/m3 at sea level (obviously we're not interested in sea level, but at least it's wrong in a known way - the ash measurement is a sea-level one and I guess RR's figures are test-stand measurements, so it's consistent) that would be 444m3 of air a second and 0.133g of ash a second - 478g of ash per engine-hour.

(Although, the -535 is a very high bypass turbofan, so perhaps we need the core mass flow...)

One can simply divide by the by-pass ratio of 4.3.

But there is the issue, under which conditions is the mass flow rate 1177 lb/s? We probably should consider a density figure at pressure and temperature corresponding to a typical cloud level. You can take standard atmosphere data etc.

However there is another estimate, based upon speed and diameter. Take the fan diameter, 74.1 in. Calculate the area. Divide my the by-pass ratio. If I do that, assume a speed of 180 m/s, for 0.3 g/m3, I end up with actually a very similar figure, 126 g/hour (assuming no algebraic error...) Of course one would hope crossing an ash zone would take less than an hour.


(From peter_we)

Thats a pretty high level.
BTW, indeed the new threshold figure of 2 g/m3 comes across as not very conservative. I would have expected them to pick a figure more like 0.5?

[slip and turn]

More accurate mapping of ash cloud with Risø DTU?s wind energy measuring equipment (http://www.risoe.dk/en/News_archives/News/2010/0421_LIDAR_askesky.aspx)

[peck]

In the UK MET charts posted by kyloe (#2186) the black area according to the label is the zone "that exeeds accepted manufacturer tolerance levels"

I´ll appreciate if somebody can give me the figure for that level.
¿some ash concentration? ¿An envelope for all turbines?

[Finn47]

Here´s a link to new hi-res pictures of the Hornet engine published by the Finnish Air Force today:

Puolustusvoimat - Frsvarsmakten - The Finnish Defence Forces (http://www.ilmavoimat.fi/index.php?id=1156)

Like has already been said, no significant damage was found, only "concentrations of foreign materials", partly melted, but it´s plain to see that these spots do not even come close to blocking any of the cooling holes in the turbine blades. On the other hand, the occurrence took place in the morning of the 15th, before any restrictions even had been put in place.

[Stoic]

I am amazed at the amount of people looking for heads to roll when all those heads did was follow the rules.I almost wrote, "Surely not the Nuremburg defence", but decided against. Instead may I refer you to the following quote:


Rules are for the guidance of wise men and the blind obedience of fools. (Solon, the Lawmaker of Athens, d. 559BCE) Actually I think it was Douglas Bader!

As others have pointed out, there was obviously a problem with the rules. There is never zero volcanic ash in the atmosphere. We have always coped around the world until an invisible plume hit the UK. Thank heavens we have leaders like Captain Willie Walsh to sort things out.

Regards

S:)

[BAMRA wake up]

Forecast models and charts fairly consistent on a gradual change to southerly winds, at least over the UK, overnight Friday/Saturday,

UKMO surface charts to T+120
Metbrief - Met Office Analysis and Synoptic Weather Forecast Charts via Wetterzentrale (http://www.metbrief.com/EGRR.html)

300mb forecast charts to T+120 (rh side of page)
CRWS Jet Stream Forecast Map Menu (http://squall.sfsu.edu/crws/jetstream_fcsts.html)

Here's hoping those lows approaching from the SW are more vigorous than forecast.

[Pace]

S

I think the argument was more about to many cooks and the fact that the tests needed to relax the "rules" could have been done days ago if what was said on the BBC was anything to go by.

Another reason why there has never been a statue made of a committee

Yes there will be a big row over who pays and maybe with some justification an expensive lesson to be learnt all round :sad:

Pace

[Sunfish]

The number of pompous punters here who are outraged that airspace was closed at all because the problem doesn't really exist is irritating.

The number who wonder why "tests" weren't done immediately is frightening.

The number who believe that the Government vacillated over decision making after tests and consultation is mind boggling.

Let me make a number of things quite clear.

1. The problem is real. Yes, I know volcanoes erupt all over the world. I know that there are sand storms in the Desert and dust in the air. I know intrepid pilots fly around erupting volcanoes. I know that some European airports remained open. The problem however is that this particular dust from this particular volcano thanks to this particular weather system stuck itself in large quantities over Britain, and it has the capacity to bugger up very expensive jet engines that are not quickly replaceable by the manufacturers. I know you paid your Twenty quid to get to Paris, but I am not going to risk wrecking Ten million dollars worth of engines to get you there today.

2. Tests were done immediately. Do you think the Government keeps a jet already wired up and on standby to test for volcanic ash? Is there a submarine kept ready and waiting to check the ocean floor for undersea earthquakes? Of course not. Tests were carried out. Did you know it takes time to design a test? It also takes time to prepare for a test and then analyse the results.

3. Vacillating Government? Tests had to be done. Manufacturers had to be consulted. The results of the tests had to be analysed. There are also regulatory frameworks that must be followed because they have the force of law. This takes time. Do you expect the Government to take a billion dollar bet without proper advice, just so that you can get your sorry backside to Amsterdam to smoke dope? I happen to think that Five days from whoa to go is a pretty snappy response where a technically, scientifically and operationally complex decision has had to be made.

Furthermore, next time the airspace is closed again because of this or other eruptions, you will have no further grounds whatsoever to complain.

Thank you to the person who posted the high resolution images of the F404 nozzle guide vanes and first stage blade. I have to take issue with your view that there was "no damage'. To make that statement would require the sectioning of at least one each of those hollow components to see what has been deposited internally, as it is internal build up that will have the most effect on blade and vane cooling.

[Stoic]

Hi Sunfish

The problem is that for the past week in the UK we have had brilliant, clear blue skies. In 1940 we had the same. Then the sky was full of aeroplanes. Our parents called it Battle of Britain weather.

This past week the sky has been empty of aeroplanes. Brilliant, clear blue skies. Volcano weather! Well, that is how I shall remember it.:)

Regards

S

[Pace]

Sunfish

I was flying a business jet up north hours before the airspace was closed if you PM me I will give you a link to a video I made from the cockpit.

Beautiful day 100 miles vis at FL250 with well pronounced and broken cumulus well below.

The MK1 eyeball is the best way of detecting particles either water or dust. Clear air is clear air. I find it hard to understand claims of invisible.
Pollution in dust form is visible to pilots either as a haze or thin cloud and usually with a slight colouration.

I take your point on looking vertically but horizontally NO unless of course your in cloud or flying at night.

Did the various groups involved do their best within the regs without doubt

Were we victims of our own burocracy possibly? I also take the point of hindsight and could things have been done differently.

Regardless there will be finger pointing as the huge cost and who bears it hits the courts.

Pace

[breakadjuster]

I heard a roumor that this incident when it lost its engines one of the crew was out walking around the cabin at the time. It was saved by the Flight Engineer and the other pilot, is this correct, if it is, what a fantastic effort by those on the flight deck!!

[Airbubba]

I heard a roumor that this incident when it lost its engines one of the crew was out walking around the cabin at the time.

From Wikipedia:

Shortly after 13:40 UTC (20:40 Jakarta time) above the Indian Ocean, south of Java, the flight crew (consisting of Senior First Officer Roger Greaves and Senior Engineer Officer Barry Townley-Freeman while Captain Eric Moody was in the lavatory) first noted an effect on the windscreen similar to St. Elmo's fire.

British Airways Flight 9 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/British_Airways_Flight_9)

[WojtekSz]

Pace:
The MK1 eyeball is the best way of detecting particles either water or dust. Clear air is clear air. I find it hard to understand claims of invisible.
Pollution in dust form is visible to pilots either as a haze or thin cloud and usually with a slight colouration.
I take your point on looking vertically but horizontally NO unless of course your in cloud or flying at night.of course you are right: a well trained or experienced eye will see the ash in the clear air. It has been cleary demonstrated by german and british research flights where lidar measurements were taken.
The question is how to standardise or validate the eye sightings against any definite level of aceptable ash contents in the air. The right answer was given in the documentation from the engine manufacturesre: avoid ANY area are where there is detectable ash. And since clouds do happen even in England ;) the NATS/CAA approach was justified.

[peter we]

As others have pointed out, there was obviously a problem with the rules. There is never zero volcanic ash in the atmosphere. We have always coped around the world until an invisible plume hit the UK. Thank heavens we have leaders like Captain Willie Walsh to sort things out.


Don't forget that WW is effectively responsible for the zero figure due to the airlines long standing refusal to provide provide an alternative figure.

He is also partly responsible for the chaos as he must have been fully aware of the risk of an Icelandic eruption and the potential effect it would have had on the industry - but did nothing to mitigate it until after the issue became a real problem. That indicates piss poor planning.

[Halfnut]

Sooooooooo how long was that Finnish Air Force F-18 up?

Did it do multiple sorties transiting the ash clouds several times climbing and descending for eight to ten hours a day like a B-737 would or did it stay local for only an hour or two and then got it's wings clipped?

As the weather has changed we'll never know.

[yoganmahew]

@anotherthing
HMG acted very poorly (well, very seldom) throughout this whole episode :=
Make up your mind.

Either it is "ridiculous and ignorant" (your words) to accuse the authorities of not being competent, or it is not. Or perhaps you are only accusing them when they don't agree with you?

Personally, as SLF with a cancelled business trip to a country that is well used to both volcanoes and crashing planes, I don't care either way, but at least be consistent.

[PaleBlueDot]

WojtekSz, Pace:
The MK1 eyeball is the best way of detecting particles either water or dust. Clear air is clear air. I find it hard to understand claims of invisible.Pollution in dust form is visible to pilots either as a haze or thin cloud and usually with a slight colouration.I take your point on looking vertically but horizontally NO unless of course your in cloud or flying at night.
of course you are right: a well trained or experienced eye will see the ash in the clear air. It has been cleary demonstrated by german and british research flights where lidar measurements were taken
You both have wrong underlining assumption: That ash is only possible pollutant in the air. It is not possible to differentiate between dangerous pollutant - ash - and anything else.

[visibility3miles]

Sunfish -- Wise advice.

Pace --Clear air is clear air. I find it hard to understand claims of invisible.
Pollution in dust form is visible to pilots either as a haze or thin cloud and usually with a slight colouration.

As someone living in an area with a huge pollen count every Spring, including now, clear air and blue skies do not stop me from teary eyes, runny nose, and sneezing, even if I can't see what I'm breathing.

The picture of the tiny vents use to cool the turbine blades gave me pause for thought, as have comments on the possibility of pitot tubes clogging.

After all, isn't the Air France crash in the mid-Atlantic attributed in part to misleading air speed from pitot tubes clogged with ice? What's the difference between ash and ice, aside from clear skies and sunny weather, and the relative (?) ease of switching to VFR?

[Pace]

You both have wrong underlining assumption: That ash is only possible pollutant in the air. It is not possible to differentiate between dangerous pollutant - ash - and anything else.

Where have I assumed that ash is the only pollutant in the air? I do assume that any pollutant which is dense enough to cause a problem will be visible in clear air.

If you are flying in an area with known volcanic ash I would assume the worst and that any pockets of mist or thin cloud especially with a pollution colouring is likely to contain ash and would avoid flying for prolonged periods in such pockets.

Equally a pilot will avoid flying in visible moisture ie cloud at temperatures of zero or below when that cloud is icing up his aircraft.
He will climb descend or avoid to get out of the icing situation.
As long as the pilot is visual his best means of detection are his eyes. most of this week above 5000 feet there has been very little cloud over a large portion of the UK and below 5000 feet well broken cumulus with suoerb visibility above.

What's the difference between ash and ice

One is a solid particle the other is formed from a liquid and is accumlative they are very different in form and how they react with the airframe.

Pace