|Volcanic Ash and Aviation Safety
ever-growing reliability of the turbojet engines of air transport
aircraft today allows twin engine extended range operations globally on
routes where previously only three- and four-engine aircraft could
travel. Threatening that reliability, however, is a hazard capable of
silencing these engines under the worst of conditions—volcanic ash.
There are 1,500 known volcanoes around the world, and 600 of them are
currently listed as active. Collectively there are 55 to 60 volcanic
eruptions annually, and monitoring records tell us that some of these
explosive eruptions are propelling volcanic ash to the thirty- and forty-thousand foot flight levels traveled by the airlines. Commercial
aircraft encountering ash spread by such eruptions have experienced
multiple engine flameouts.
ALPA Safety, through its Volcanic Ash project under the Air Traffic
Services Group, has devoted several years to expanding the database of
operationally relevant information on this potential hazard and
improving the warning system necessary to reduce unplanned encounters of
hazardous ash clouds.
The information under this Banner may be useful toward understanding
the hazard; understanding recommended practices for avoidance, if
possible; achieving survival in the event of an unexpected encounter;
and finally, reporting the experience.
A recommended starting point is the video, “Volcanic Ash: An Aviation
Hazard of Explosive Proportions.”