Hayli Gubbi Volcanic Eruption
Context:
The Hayli Gubbi volcano in Ethiopia erupted on November 23, reportedly for the first time in around 12,000 years
Ash clouds from the eruption drifted over Yemen, Oman, Pakistan, and entered India, disrupting flight schedules and prompting an urgent advisory from the DGCA
SCIENCE OF VOLCANO ERUPTIONS
Volcanoes erupt because of how heat moves beneath Earth's surface.
Deep within the planet, it is so hot that rocks slowly melt to become a thick, flowing substance called magma.
Since it is lighter than the solid rock around it, magma rises, collecting in chambers near the surface.
As these chambers fill up, pressure exerted on the surrounding rock increases.
Eventually, some of the magma pushes through the cracks in the rock, and vents onto the surface.
This is a volcanic eruption
The magma that has erupted is called lava.
About Volcanic Ash:
It is a mixture of rock, mineral, and glass particles expelled during an eruption.
It often contains a high amount of silica
Physical Properties:
The particles are very small (less than 2 mm in diameter), pitted, and have low density.
Unlike wood ash, volcanic ash is extremely hard, abrasive, and has jagged edges
It is accompanied by water vapor and toxic gases.
Due to their tiny size and low density, the particles that make up volcanic ash can travel long distances, carried by winds.
Why is it a Threat to Aviation?
Melting Point Differential:
The hottest part of a jet engine operates at over 1,500°C, whereas volcanic ash (silica) melts at around 1,000°C
Mechanism of Failure:
When ash enters the combustion chamber, it melts into a substance similar to molten glass
This molten material coats the turbine blades, preventing them from functioning and potentially causing the engine to stall or shut down
The abrasive particles can clog sensors, impair pneumatics, and render cockpit windscreens opaque.
Historical Precedence:
The danger is well-documented, with notable incidents including a British Airways Boeing 747 (1982)and a KLM Boeing 747 (1989) suffering all-engine failures after flying through ash clouds.