p4 todays Grauniad quotes one Jim McKenna, (CAA's Head of Airworthiness) and in a long, well written and balanced (IMHO) summary states, inter alia:
Initial no-go areas defined as those the model predicted to have more than ten billionths of a gram per cubic metre.
After tests and consultation with Airframe and Engine manufacturers:
1. Anywhere with more than 2000 micrograms/cu.m. = No Fly
2. 200 - 2000 micrograms /cu.m. = Can fly with 'precautions', taken by me to mean extra inspections, particularly of engines.
3. < 200 micrograms / cu.m = no threat.
Enjoy, I'm off to MXP.
