The question is: How does ash affect airplanes ?:
Less safety in the cabin
The presence of ash in the middle of the flight reduces operational safety in the cabin. Above all, due to the impact of these particles on the cockpit windows.
If this volcanic material enters the pilot probes and static probes it can cause errors in the reading of speed and altitude.
The ashes that are introduced into an engine can melt inside and clog parts of the turbines and injectors.
In addition to triggering cooling system failures, ash can contaminate cabin air and create disturbances in the ventilation and pressurization systems of an aircraft.