one green and hoping (post #79)
I seem to recall the pilot mentioning that volcanic ash didn't appear on weather radar, and hadn't been informed of the eruption from ATC.
Because the ash cloud was dry, it did not show up on the weather radar, which is designed to detect the moisture in clouds.
The investigations eventually led to...
It was recognised that there was an issue following the incident in 1982 with the British Airways Flight 9 and therefore the ICAO established the Volcanic Ash Warning Study Group in 1982. Due to the difficulty in forecasting accurate information out to 12 hours and beyond the VAAC were set up by the ICAO as part of IAVW.