Volcanic Ash

You may recall the eruption of the Icelandic volcano Eyjafjallajokull in April 2010 caused massive disruptions to air travel in Europe.

Reference AIM AIR 2.6 and AIM MET 2.5

There are numerous hazards associated with volcanic ash:

• damage to surfaces, windshields, powerplants
• read about KLM 867 which had a quadruple engine failure near Anchorage Alaska in 1989
• contamination of heating, ventilation, hydraulic and electronic systems
• adverse effects on weight and balance

Ash can rapidly reach heights in excess of FL600, and weather radar is not effective in detecting it.

The best preventative measure is avoidance, although this could be difficult in IMC or at night.  "St. Elmo's fire is usually a telltale sign of a night encounter, although rapid onset of engine problems may be the first indication."  Refer to PIREPs, SIGMETS and NOTAMs and advice ATC if an eruption or ash is observed to help warn others.