Saturday, December 10, 2011

PICTURES: Flying through the ash. It's EZY: During the European volcanic ash grounding in April 2010, EasyJet's head of engineering Ian Davies began to wonder if there was a better way, so he googled volcanic ash and emerged with a name: Dr Fred Prata of NILU, the Norwegian Institute of Air Research.

Dr Fred had been working for years on systems for tracking volcanic ash by satellite and was probably the world's foremost expert on it, so Davies hit the jackpot first time. But Dr Fred was also working on developing an aircraft-mounted infra-red ash sensor, called AVOID, that could provide pilots with a display a bit like a weather radar showing them where the worst ash was so they could avoid it. At FL200 it can see ash about 100km (54nm) ahead. Airbus will soon be joining the trials to provide the high-altitude test capability.

Ian decided EasyJet should get involved, because someone had to. He found out that Dr Fred knew a whole load of stuff that could have made April 2010 a relatively benign event, but nobody was listening to scientists then, least of all to Fred. It took Eyjafjallajokull to wake the authorities up. They are listening now.

EZY and Dr Fred's NILU offshoot Nicarnica Aviation, with the help of a piston-engined ultralight aircraft operated by the University of Dusseldorf, have just finished a fortnight of trials carried out in the shadow of Mt Etna, Sicily, which is always puffing out ash. Only the quantity varies. The Flight Design CT ultralight is fitted with an AVOID pod and other atmospheric sensors.Fred and crew.JPG
L-R: Uwe Post, the pilot of the Flight Design CT ultralight, Dr Fred Prata of NILU,
and Prof Konradin Weber of Dusseldorf University. The AVOID pod is below the wing on the right

Despite the sophisticated nature of the trials, the airstrip at the base of Etna that we were operating from on 6 December - Calatabiano (near Fiumefreddo north of Catania) - was charmingly basic.
Fiumefreddo aerodrome 3.JPG
(Above) Yes, that narrow strip the other side of the hangars is the runway...

Fiumefreddo aerodrome 5.JPG
...and (above) that's the surface near the TDZ (Etna in the background)...

There's rather a lot of terrain around too...
Fiumefreddo aerodrome 7.JPG

...and here our intrepid explorers are setting off from Calatabiano
to sniff Etna's crater

EZY provided us with a chopper to chase the ultralight on its mission.
Me and we did, and this is what we saw...

Microlight over Etna.JPGThat's Etna in the background, covered in cloud. Not the best day for seeing everything.

Etna from copter.JPG...But (above) the eyebrow window's tinted glass cuts out the glare so you can see where the ash is.

And here's a helicopter view of our return to the aerodrome...
Copter approach.JPGBut what's it all for?
Sensors 1.JPGThat's the AVOID pod. It's very expensive, making it rather unlikely that airlines will choose to fit it. But EZY is going to fit it to 20 of its A320 series fleet, and it hopes other European carriers will fit about 80 more to aircraft based around the continent. If they do, this exercise will achieve much more than just providing tactical avoidance capability to the airframes actually fitted with AVOID.

When the next ash event happens, the crews of these aeroplanes can send back pireps telling ATC where stuff actually is. This enables comparisons to be made with the predicted location of the various densities of ash, so the predictive algorithms can be refined, and the accuracy of the surveillance picture provided by satellite sensors and ground-based lidar stations can be checked in reality.

The whole exercise is about building confidence in the total system, and continually adding to the knowledge base. So when Katla blows its top, we know how to react.

Well done EZY, Dr Fred Prata, NILU, and Prof Konradin Weber of Dusseldorf University.

In fact the whole team...
Landing at the end of the day. Job done (below)
Fiumefreddo aerodrome 8.JPG

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