Volcanic Ash

Volcanic ash consists of fine particles of pulverized rock, minerals, and volcanic glass ejected during a volcanic eruption. Volcanic ash clouds represent one of the most serious hazards to aviation because the particles can cause catastrophic damage to jet engines and aircraft systems.

Effects of volcanic ash on aircraft:

• Engine failure: Ash particles melt in the combustion chamber (which exceeds ash melting temperature) and re-solidify on turbine blades, blocking airflow and potentially causing complete engine failure
• Windshield damage: Abrasive particles sand-blast the windshield, reducing it to near-opacity
• Pitot tube blockage: Leading to unreliable airspeed indications
• Contamination: Ash enters environmental systems, affecting cabin air quality

The most dramatic volcanic ash encounter was British Airways Flight 9 in 1982, which flew through the eruption plume of Mount Galunggung and lost all four engines (they were eventually restarted at lower altitude).

Nine Volcanic Ash Advisory Centers (VAACs) worldwide monitor volcanic activity and issue advisories. The standard recommendation is zero tolerance — avoid all volcanic ash clouds entirely.