[Coolcirrus]

The so-called "test flights" should have produced clear evidence that aircraft are capable of negotiating certain prespecified atmospheric conditions. If so, what were the specified conditions and where are the data? It appears that numerous aircraft on Sunday flew in relatively low-ash or even ash-free areas of Europe. When these aircraft landed there were almost instantaneous claims from various airlines that no problems had been encountered, yet insidious damage to an aeroengine by repeated exposure to particulates would surely only be detectable by a proper engine stripdown after having conducted several test flights? Ideally, one would include some worst-case conditions in the test battery to provide a safety margin, just as in aircraft test flights. Using older aircraft with parachutes would make a lot of sense! Do we seriously think that BA would send up an expensive 747-400 into an ash cloud? Of course not! I take the event to be purely a publicity stunt until such time as they provide actual data to prove otherwise.

I have no objection to the "no ash" threshold being revised if it is done in a scientifically transparent and defensible way. It is a standard process in risk assessment that thresholds are objectively revised in light of new evidence. But, where exactly is this new evidence? Sending a few planes up for random forays on unspecified missions and then not openly disclosing the findings is not the way to go about this!

[EllyTech]

It was only reported that no problems were experienced during the flights ...

[Coolcirrus]

Quote

EllyTech - 19/4/2010 19:03 It was only reported that no problems were experienced during the flights ...

But that's pretty meaningless isn't it? What would one expect from one short flight? :s

[EllyTech]

Quote

Coolcirrus - 19/4/2010 19:10

Quote

EllyTech - 19/4/2010 19:03 It was only reported that no problems were experienced during the flights ...

But that's pretty meaningless isn't it? What would one expect from one short flight? :s

Perhaps there *is* something positive to be said regarding no damage to fuselage as this would indicate little in the way of dust particles entering the engines elsewhere - ?

[John Mason]

I think NAT are a pretty good authority on this. They get their info from the right places. Anybody who thinks it is alarmism can try the following experiment:

1) take a quartz pebble (can be found in most gardens)

2) carefully break into little bits with a heavy hammer (eye goggles ESSENTIAL)

3) place the bits on a 1" steel plate

4) continue hammering (goggles ON) until it resembles flour in consistency and grainsize (this may take a while)

5) scrape into an old cup

6) add a bit of engine oil

7) mix to a paste

8) remove the top of the carburettor in your car

9) add a couple of generous pinches of the mixture

10) replace the top of your carb

11) attempt to go for a long drive

12) see what happens

And THAT's at low temperatures!!! 

Cheers - John 

[summer '85]

Quote

Big Dave's Gusset - 19/4/2010 14:45

Because Europe is the affected area, it is densely populated with a large concentration of some of the world's busiest airports and the volume of flights is probably higher than any other area of the world apart from the NE United States . The NW where the volcanoes are is far more sparsely populated and the skies probably far less busy, and therefore may not provide a good comparison.  If you look at the ash spread of the 1980 eruption it affect only states such as Washington State,  Montana, North & South Dakota, Wyoming, some of Idaho:

"Air travel was disrupted for a few days to 2 weeks as several airports in eastern Washington shut down because of ash accumulation and poor visibility. Over a thousand commercial flights were cancelled following airport closures."

http://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens

See also http://vulcan.wr.usgs.gov/Volcanoes/MSH/Maps/map_may18_ash_path.html

But what goes for the USA doesn't always apply to other parts of the world despite what Hollywood tells us, that's why I asked specifically about Europe.

Pretty obvious this answer, Dave, no. Otherwise, the media would have cited past examples for Europe and certainly I can't recall past examples. However, it is not for the rest of the world though.

For instance, how often has Indonesia airspace  been affected, mount Pinatubo probably affect airspace in the Far East

[Dave W]

“The science behind the model we are running at the moment is based on certain assumptions where we do not have clear scientific evidence,” he said.

“We don’t even know what density the cloud should be in order to affect jet engines. We have a model that runs on mathematical projections.

It is probability rather than actual things happening.”

Sound to me like they are shooting the messenger! Surely it was not up to UKMO to do those tests on jet engine ash density safety affectiveness?

[skanky]

Where's that quote from, Dave?

[Dave K]

This is from the Wall Street Journal:

"Until the latest volcanic eruption in Iceland, air-safety regulators were nearly unanimous in adhering to a "zero tolerance" rule for flying through ash clouds. The International Civil Aviation Organization, an arm of the United Nations, for many years urged airlines to avoid such particles if at all possible, and recommended a minimum warning time of five minutes so pilots could avoid flying through the stuff....

In 2000, a McDonnell Douglas DC-8 operated by NASA suffered significant engine damage en route to Sweden from California, after flying through a cloud of volcanic ash near Iceland. The engines on the research plane didn't quit, but mechanics were amazed at the extent of the damage they discovered. All the nearly new engines had to be replaced."

Seems simple "lesson learned" to me then, firstly Jet Engine manufacturers need to set the tolerance thresholds and the Met Agencies need to be able to accurately measure concentrations at various levels on a near constant basis during VA cloud events.

BUT

"Experts said deciding where and when to fly can be particularly tricky because pilots often can't see ash plumes clearly and current technology isn't good enough to use small balloons or unmanned aircraft to map the extent and movement of ash clouds."

catch-22 then. Just one of those cases where natural events are getting the better of us.

[Dave W]

Quote

skanky - 20/4/2010 09:26 Where's that quote from, Dave?

This article http://www.telegraph.co.uk/news/7608722/Volcanic-ash-cloud-Met-Office-blamed-for-unnecessary-six-day-closure.html

[skanky]

Quote

Dave W - 20/4/2010 09:37

Quote

skanky - 20/4/2010 09:26 Where's that quote from, Dave?

This article http://www.telegraph.co.uk/news/7608722/Volcanic-ash-cloud-Met-Office-blamed-for-unnecessary-six-day-closure.html

Thanks, I agree with you there. That's a very (typically) one-sided article.

[John Robert Mellor]

Quote

skanky - 20/4/2010 10:04

Quote

Dave W - 20/4/2010 09:37

Quote

skanky - 20/4/2010 09:26 Where's that quote from, Dave?

This article http://www.telegraph.co.uk/news/7608722/Volcanic-ash-cloud-Met-Office-blamed-for-unnecessary-six-day-closure.html

Thanks, I agree with you there. That's a very (typically) one-sided article.

Indeed....diidn't someone tell them that it is NATs that issue the No Fly order, not the Met Office. Another opportunity to have a dig at the Met Office.

 

[PK2]

Quote

John Robert Mellor - 20/4/2010 10:12

Quote

skanky - 20/4/2010 10:04

Quote

Dave W - 20/4/2010 09:37

Quote

skanky - 20/4/2010 09:26 Where's that quote from, Dave?

This article http://www.telegraph.co.uk/news/7608722/Volcanic-ash-cloud-Met-Office-blamed-for-unnecessary-six-day-closure.html

Thanks, I agree with you there. That's a very (typically) one-sided article.

Indeed....diidn't someone tell them that it is NATs that issue the No Fly order, not the Met Office. Another opportunity to have a dig at the Met Office.

It seems it's becoming clear why the MetO put these statements Andy noted into their advisory now

Quote

Andy Mayhew - 19/4/2010 21:27

Latest News Release update from the Met Office (note this may change with the next update)

Quote

Volcanic ash update

Last updated: 2112 BST on Monday, 19 April 2010

It is for the aviation industry and regulator to set thresholds for safe ash ingestion. Currently, world-wide advice from ICAO is based on engine and airframe manufacturers stating that aircraft should not be exposed to any volcanic ash.

Met Office and NERC observations are consistent with Met Office model forecasts for spread of ash over UK and north-west Europe and NATS are continuing to advise restrictions on UK airspace until Tuesday morning.

[John Mason]

Gotta cross-post this one, from elsewhere:

"But the aviation industry wasn't grounded by a volcanic dust cloud. It was grounded by a Met Office mathematical model which said there was a volcanic dust cloud, when there wasn't. Such is our faith in computer models that it was four days before anyone went to look. The only simplification needed to the system is the sacking of the head of the Met Office."

Priceless!! Absolutely priceless!!

Cheers - John

[John Robert Mellor]

Quote

John Mason - 20/4/2010 10:50

Gotta cross-post this one, from elsewhere:

"But the aviation industry wasn't grounded by a volcanic dust cloud. It was grounded by a Met Office mathematical model which said there was a volcanic dust cloud, when there wasn't. Such is our faith in computer models that it was four days before anyone went to look. The only simplification needed to the system is the sacking of the head of the Met Office."

Priceless!! Absolutely priceless!!

Cheers - John

:s   I don't who posted that John, but I can say that definitely has a style not too far removed from one of the more, should I say,  controversial posters on here, from the south-east of England ;)

[skanky]

Did anyone see the BA test pilot on Breakfast this morning? I didn't get a chance to watch or listen properly, but it seemed that he stated that the BA test flight avoided any restricted airspace - that is the areas with the highest concentrations of ash. I may have got that wrong, so can anyone confirm or deny? Also, it would be interesting if there's a comparison of their flight path to the advisory areas at the time - something you'd hope a newspaper or other media might have knocked up. Also for the other "test" flights. Anyone seen one?

[Paul Sherman]

Had 3 KLM Flights go directly above my House just NE Of Southend this morning. First one at 8am, 2nd one at 10am which went back Eastbound around 40 minutes ago, these took off from Schipol and went back to same airport. 3rd KLM Was going from Schipol to Sao Paulo, all flights were at 33,000ft on the radar I was watching. It was wierd seeing the Contrails in the clear blue skies again.

Paul S 

 

[Lightning Hunter]

I was suprised to look up and see a contrail from a 747 at about 8:45 this morning above Southampton, despite being able to see ash in the sky - maybe they were above the ash?