There is probably a chance of contaminated air getting into the oil system via balancing air for the labyrinth seals.

PWC recommend an oil change in the event of flight through volcanic ash.

Fly3est,

I didn't say Oil analysis would be in this case.

No, 'scopes are not the be all and end all, i didn't say they were either.

And it depends on the engine type what you can inspect, on the engines i have owned (all off wing from 737) have been able to inspect all the LPC, all the HPC and the T1 blades and disks. I have about 40 scope video on my shelf behind me, some of those engines I have owned some I have not.

As I said, what they enable is an understanding of what is going on, or rather, what has gone on in the engine without having to break it open and subject yourself to unnecessary maintence.

In the case of contaminant ingestion in this case, we know that damage can occur from the combustion chamber backwards and with the T1 operating higher than the material limits, as such a scope of the T section will provide an indicator of any damage due to contaminant ingestion.

I would rather scope an engine than not.

The 'ash cloud' charts produced by the Met Office are computer predictions of where the ash might be, taking into account the wind at various levels. As is stated below the maps, they do not indicate the concentration (if any) of the ash.

Should we stop calling it an ash cloud and now call it an 'area of computer predicted possibility'?

Right I have counted to ten!

Given the circumstances it was probably prudent to take drastic action last week but given the nature of the problem several things should by now have happened and have not.

Those making the decisions should have instigated a comprehensive flight test program in collaboration with the engine and airframe manufacturers. Had they done so we would now have some solid data on which to base the decisions being made. However, none of this has happened or at least only to a very limited degree and it has fallen to a few airlines to put aircraft up, at their own expense, to see what effects the ash cloud actually has, apparently only to have their findings largely ignored.

Military fighter engines are very different animals to civilian engines and may be more susceptible to such damage. The point is we need data and we need to start getting it now as this volcano is not going away anytime soon it would appear and even if the weather pattern moves the cloud away we a very likely to be back in this position within a few weeks.

Doing nothing and closing airspace as a precaution is not not an option, we face an economic catastrophe and not just in the airline world. If this ash cloud is dangerous fair enough but we need data and we need it now. What we don't need is a devastated economy based on assumptions and poor or no science!

Spot on!

EU and national government have been too slow to act on this.

Becuase the CAA has no authority to do so on foreign registered aircraft overflying UK airspace.

Then, the CAA doesnt have the equipment or the capacity to do so.

Then, Ok they scope the engine, then what ?

It's the A&P that signs it off, he's regulated by the authority, but it's his a$$ that he signing off on a Form 1. :}

Bruce,
I think you are missing my point.
I set up spectro analysis on a small fleet of DC-6Bs way back in 1974, and it was so effective that we could tell who had been using fast idle on #4 to boost cabin ground cooling.(High Si)
Thing is, it is not normal to check for Sulphur which is not an expected wear product. This was the clue for NASA.

How frequent are scheduled Borescope checks? What is the interval?
I am aware of blade contamination from sulphur products in fuel (and additives eg water methanol in turbo-props) We used to walnut shell blast compressors for salt air contamination. Volcanic ash was not among the contaminants we used to to deal with. What are the procedures?

It certainly seems to me that not enough data gathering is going on. The handful of planes going up through the levels and hanging around for an hour or so trying to make a point didn't really prove much because they couldn't measure what level of ash they actually encountered.

The NASA document on their accidental ash encounter was a real eye opener on the insidious danger posed by the cumulative effect of diffuse ash. Certainly scared me.

Ideally we'd have got all the military/scientific aircraft available worldwide flying round and round for as long as possible over the last week then getting their engines boroscoped/stripped down in an effort to quantify things. Until we're able to say something like x g/m3 = y safe hrs between boroscope inspections then we're stuck I'd guess.

Without this aren't we looking at a future of trying to operate long term with long periods of lockdown followed by massive repatriation efforts. Would the public adjust to that, going on holiday thinking they had a 50/50 chance of getting home on time?

Unless we put this volcano out of course. I saw this cartoon once and all they needed was a really big bucket of water.

Bruce,

Only scope UK operators ?

Maybe the CAA obtain the services of an engineer with a borescope and expertise in analysis of the engine core ?

Then, assess the results and come to a conclusion - maybe publish the results for all to see ?


I'm no expert but it seems logical to me, purely to gain an insight of some sorts if nothing else.

I really can't see the objection to an investigation of the exposed airframes and engines in order to clear this whole sorry mess up and all being well get things flying as normal.

Bruce I agree 100%, I am just raising a question as to whether a borescope inspection is sufficient to clear a passenger carrying flight following events, the effects of which are relatively poorly understood. I am thinking a comprehensive test flight through the anticipated environments, followed by a thorough engine inspection upon which less intrusive maintenance operations / inspections may be based, might be a more robust solution to an otherwise much speculated issue?

I am coming from a point of view of getting aircraft flying whilst mitigating as much risk as possible in the interests of safety, as opposed to "I have seen tons of aircraft on an internet screen so it must be alright" - Not that I am suggesting that's your point of view, I understand we are both batting off the same crease. :ok:

FT

ZQA297/30

Good questions! I know the engines are scoped on major checks but not on daily or weekly checks. This would need to change whilst this cloud is affecting airspace. I have no doubt we would need to carry out a range of checks on the engines and pitot static systems post flight as long as the aircraft are operating in the area of the ash cloud.

Again these are procedures I hope someone is working on now. I believe the BA aircraft will have been subjected to a wide range of inspections as it is no coincidence the aircraft flew to Cardiff, as this is a heavy maintenance base for BA.

I suspect the authorities have had a full report from BA but I doubt BA will publish this to the public other than making vague statements for very obvious liability reasons.

Swiss fly through the cloud above Switzerland.
 

Diamond Airborne Sensing : A Diamond aircraft delivers volcanic ash cloud measurement data

"Since Saturday, a Diamond HK36 MPP (Multi Purpose Platform), operating at MetAir, the Swiss airborne measurement company, is providing the only specific measurement data from the ash cloud of volcano Eyjafjallajökull.

...The results clearly show that the ash particle concentration is remarkably high and noticeably decreases visibility. Additionally, the ash cloud loses altitude very quickly. At the beginning of the measurement flights the cloud was at an altitude of 5000 meters but only nine hours later it had descended to just 2000 meters....

.....are able to fly in the heavy aerosol particle concentration due to being equipped with a special air filter."

Video of the flight here.
Schweizer Fernsehen: SF Videoportal - Tagesschau - Flug in Aschewolke
The HK36 MPP is a single engine internal combustion engine aircraft.


Mickjoebill

IFR VFR
 

Could somebody explain why VFR and IFR are treated differently?
If this is about ash density VFR / IFR seems to be irrelevant and a VFR flight will be just as safe / dangerous as an IFR flight in the same density

or is it just simpler to control ifr traffic ?

ZQA297/30,

I think we are aiming for the same target, but from different angles.

In terms of scheduled borescope inspection, thats up to the operator, on how they want to monitor the condition of their engines. As I am sure you are aware an engine in the shop is not only costly in terms of maintenance but also in terms of down time, unless of course you have a spare engine you can spin on wing in the interim, then of course if you have multiples then what about spare engine quantities and that is a lot of money to tie up and of course your spare engine is calendaring out while its on a stand, unless it is subject to a an approved storage program.

The upshot is that, as I am sure you are aware, an operator wants to preserve its engines.

An operator i used to work for, it was a sackable offence to go over 95% The types we operated would get off at 92% MTOW, hot and high at our shortest runway limits. Anything above that was toasting the engines and burning dollar bills.


What are the concentration levels ?

Like I said, we seem to be on the same target but from different angles.

Tentative flights are fine, if frequent inspections are made, but a return to full scale ops is reckless.

The problems in continental Europe will be less than in the UK for the reason I clearly explained - the plume passes over the UK in a narrow corridor before spreading east and west as it reaches the Channel, diffusing as it spreads. If you cannot grasp that, I pity you.

At no point have I back pedalled - you are claiming a false victory because you, like many others, can't understand the logic of the argument. I have maintained throughout that we simply don't know whether the ash levels are safe or not because too little research has been available. The evidence seems to support the view that it is unsafe, but those supporting a return to normal ops are keener to show traits of machismo than prudence or intelligence.

The severity of the implications of this risk demand that it be treated with the utmost seriousness and caution. It is one thing for an aircraft to have failures of all engines, but it is quite another to have dozens of simultaneous emergencies, with the ATC and airport saturation which would occur. Just imagine two or more aircraft needing to make glide or partial power approaches to the same airport at the same time, and other aircraft with damaged engines having to hold or divert for them. Do you really want to risk being a part of that?

As I said before, I really don't know whether it's safe or not, and nor does anyone on here, but I'll hedge my bets with the cautious side, especially since they're the ones with the evidence to back them up. the old mantra of "if there's doubt" seems to be being wilfully ignored by many so called "professionals", adding weight to the companies' positions when they try to force us all to fly in unsafe circumstances and strengthening the management position of money over safety.

IFALPA spokesman Gideon Ewers just seen on BBC News stating similar thoughts with regard to inspection on aircraft exposed to low levels of particulate and stating that it is better to be on "the safe side" with regard to flying under the current circumstances.

comments/thoughts ? personally, seemed logical to me.

BA on the move...at last!
 

Understand from a source in BA that at least 6 long haul fleet flights are now en-route for LHR hoping to make it in time for this evening's 'window' as per the earlier NATS press release.

Flights all over Europe
 

Everywhere in N Europe they are now flying (flightradar24.com). But over England a big empty space. What an absolute nonsense: nobody here wants to take responsibility for the decision, nothing to do with the technicalities of ash concentrations: look at the maps from VAAC/Met Office. Its just indecision, pure and simple.

Interesting, balanced article:

The Great Debate UK Debate Archive Impact of the volcano disruption on the airlines | The Great Debate |

Au contraire. A decision was made - just one you don't agree with.

Scottish airspace has been opened - was that the result of indecision as well ?

13Alpha