Volcanic ash cloud and Private / VFR flying (merged)

[mm_flynn]

Originally Posted by Droopystop

I have to say I am torn with this ash issue. I was "stranded" for a few days, both as pilot and a passenger. On the one hand we have the "we don't know, but we reckon that ICAO say no so no flying", on the other we have the "Russian Roulette" approach to safety management. Both are equally inappropriate in this day and age.

With hindsight we can probably say

1. The ICAO documents that Europe built their response on don't at any point appear to define what an ash cloud is. However, they clearly do not require a zero ash content (that would shut down aviation as there is always a non-zero amount of ash in the air)
2. Europe coose to implement an initial policy based on a forecast possibility of ash being present (although these forecast all clearly state that the density is unknown). This is somewhat like treating the metoffice 'there could be ice in clouds below 0' routine statement as banning flight in spam cans whenever there is the possibility of a cloud above the freezing level.
3. There doesn't appear to be a single instance of an immediate flight safety incident attributable to ash densities insufficient to show as haze/cloud/St Elmo's fire. (Note - The NASA DC 8 crew had noticed they couldn't see the stars so they were in or under a layer of visually opaque 'cloud'.
4. There are a number of incidents where crew could not tell the difference between a water and ash cloud or at night unable to see the cloud.
5. Operators that frequently encounter ash conditions seem to have a policy of no IMC and no night when ash is forecast (as the crew won't be able to see the ash)

So it seems a more sensible approach would have been to require operations clear of cloud and during daylight. This would have caused some disruption but not anything like the closure of the airspace for 6 days.