Originally Posted by
tdracer
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.)
Interesting work, but it's got a long ways to go before it's ready for the primetime...
Yes, and only being able to fly in what is essentially VFR will always be a limitation of this system.
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.