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Ash Cloud Detector
Three years after Eyjafjallajokull erupted and closed most European airspace down, maybe we're getting a bit closer to a practical onboard detection system, according to Airbus.
easyJet, Airbus and Nicarnica Aviation successfully create first ever significant artificial ash cloud for test purposes. http://www.airbus.com/typo3temp/pics/6a414f29f2.jpg AVOID sensor concept proven to detect and estimate concentrations of volcanic ash in the atmosphere 13 November 2013 During the experiment the test team successfully:
An A400M Airbus test plane dispersed one tonne of Icelandic ash into the atmosphere at between 9,000ft and 11,000ft thereby creating conditions consistent with the 2010 eruption. A second Airbus test aircraft, an A340-300, with the AVOID technology fitted, flew towards the ash cloud identifying and measuring it from around 60km away. The experiment also used a small aircraft, a Diamond DA42 from Duesseldorf University of Applied Sciences, to fly into the ash cloud to take measurements which help to corroborate the measurements made by the AVOID system. The ash cloud produced during the test was between 600ft and 800ft deep measuring 2.8km in diameter. To be begin with the ash cloud was visible to the naked eye but dissipated quickly becoming difficult to identify. The AVOID volcanic sensor detected the ash cloud and measured its density which ranged from 0.1 to 1 g m-2 – or concentrations of 100 to 1000 μg m-3. This is within the range of concentrations measured during the Eyjafjallajokul ash crisis in April and May 2010. |
I hope the permanent sensor doesn't protrude into the airflow like that one?
Nice drag increase!! |
We'll see what the real engineers come up with. Grand idea, but not yet ready for Prime Time.
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On one of our science flights a fews years back someone on the team in the back got all excited about a reading and wanted us to turn around for another "sniff". As it turns out, the airplane flew through some ash and did some damage to the engines. A detector? Damage will already be done, so this will only prompt maint to do an inspection (if the damage is not severe enough to cause an engine shutdown, or worse), and maybe save the guy behind you (see the following story).
I was flying from PAFA-KONT when an Alaskan volcano was demonstrating it's thing. The ash cloud was clearly visible on a severe clear day with no other clouds visible. I gave a thorough PIREP, a KLM 744 checked in, center asked them if they heard my PIREP, they said yes...and then promptly flew into the ash cloud. After getting some power back on the heavy glider, they limped to PANC where there was reportedly $80 million in damages on the relatively new 744. :ugh: I'm not sure how practical this might be in a real world application given that after the fact is after the fact. |
Good points, Desert. But the Airbus news piece does say
an A340-300, with the AVOID technology fitted, flew towards the ash cloud identifying and measuring it from around 60km away. Also To be begin with (sic) the ash cloud was visible to the naked eye but dissipated quickly becoming difficult to identify. |
That was NASA's DC8 Desert, it's quite a well known story and yes, did a lot of expensive damage. All the instrumentation carried was "in-situe" stuff: nephelometers, cloud particle imagers and the like.
The instrument that press release is about uses forward looking IR to detect ash from a different signature to other aerosol, or background sky. It works - the only problem is that it can't see through cloud, which is a bit of a limitation. |
This was the very first 'live' test of the technology. It's still at an early stage of development. But it provided good detection ranges, more than enough to allow an aircraft to execute an about turn before encountering the ash.
The ash cloud was visible, but the AVOID system still detected it even after it had dissipated enough to be difficult to detect visually. |
Getting it to work is one thing, getting the legal liability sorted for if it doesn't next time mount unpronouncable kicks off is quite another. First few times I had to give out those sigmets I tried to pronounce that mountain's name, Impossible.
Looks like it's going to work in a similar way to the wx radar i.e. pilot sees a big red blotch, he/she will avoid. Where on the airframe will it be mounted though? |
Knowing ash is present is not enough - you also need to know where the ash isn't present or avoidance is going to be rather difficult (short of just doing a 180.):uhoh:
Interesting work, but it's got a long ways to go before it's ready for the primetime... |
Originally Posted by Una Due Tfc
(Post 8156302)
Getting it to work is one thing, getting the legal liability sorted for if it doesn't next time mount unpronouncable kicks off is quite another. First few times I had to give out those sigmets I tried to pronounce that mountain's name, Impossible.
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Originally Posted by tdracer
(Post 8156451)
Knowing ash is present is not enough - you also need to know where the ash isn't present or avoidance is going to be rather difficult (short of just doing a 180.):uhoh:
Interesting work, but it's got a long ways to go before it's ready for the primetime... The 2010 work in the UK using the BAe-146 and a downward facing LIDAR, as well as ascents and descents with that aircraft and an instrumented Do226 showed that the ash tended to form into very thin layers (say 500-1500ft) separated by multiple thousands of feet of clear air. So avoidance is theoretically do-able; however, it also showed that these layers have a complex 3D structure so it's hard to stay permanently between the ash layers. But to be fair, all the science says that the AVOID system, whilst limited, will work - and has potential to allow aircraft to significantly reduce their exposure to the ash. If it's combined with another system that's coming out of the UK work to meaningfully measure direct exposure, there's good potential to avoid most of it, then know how much an aircraft was exposed to so that maintenance can be managed. There's a future in it, but a limited one. And a lot of work to be done yet. But that's no reason not to do it. |
airsound
"So maybe this really is 'before' rather than 'after the fact'"
Before is the only practical solution. |
Genghis the Engineer
That was NASA's DC8 Desert, it's quite a well known story and yes, did a lot of expensive damage. All the instrumentation carried was "in-situe" stuff: nephelometers, cloud particle imagers and the like. |
Ash cloud detector ?!?! It may go off any time during land ot T/O in India ??:confused:
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It all boils down to risk analysis vs. investment required. For example, CFIT accidents were rather common until some 20 years ago, so the development of (E)GPWS was reasonable and appropriate, the costs of it were not prohibitive and outweighed by the gains. The same for TCAS/ACAS (however You want to call it).
Please forgive my doubts, but seeing that serious volcanic eruptions are few and far between (and VA related incidents luckily even more so) and also seeing the airlines reluctance in parting with their scarce money I cannot imagine having such a system in widespread use or even compulsory like the two previously mentioned ones in the foreseeable future. |
Quote... Generated an artificial ash cloud over the bay of Biscay by releasing a tonne of volcanic ash using an Airbus A400M aircraft.
I wonder how soon the military will be before they realise that this would be an ideal way of limiting flights over a particular hostile airspace... Could have been very useful over Bagdad or Port Stanley. Edit... Just seen that it was an A400M... so maybe they have thought of it. |
60km isn't very far, is it?
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