Volcanic ash can be transported by atmospheric winds for several days following an explosive volcanic eruption. During that time the ash cloud poses a potential hazard to flying aircraft. The abrasive effects of ash can scour windscreens to near total opacity and severely damage aircraft exteriors. The ingestion of ash can cause severe impairment of engine cooling function, internal abrasion damage to turbine blades, and even engine failure. As an aid to pilot instruction and long-term flightpath planning for avoiding airborne volcanic ash, the NOAA Air Resources Laboratory Volcanic Ash Forecast Transport And Dispersion (VAFTAD) model is used to investigate airborne volcanic Ash Encounter Probabilities (AEPs). VAFTAD is run for a volcano site with hypothetical eruptions daily at 0000 UTC, for monthly periods, using archived meteorological analyses. Visual ash cloud patterns at 12, 24, 36, and 48 hours after each eruption are statistically combined for three month periods to give seasonal AEP charts. As an added aid to long-term planning, AEP values along predetermined flightpaths are calculated and displayed. This paper focuses AEP calculations on two volcanoes with very different ash transport characteristics - Kluchevskoi (Kamchatka) and Popocatepetl (Mexico) — both of which are capable of large explosive eruptions
The 8th Conference on Aviation, Range, and Aerospace Meteorology