Why Volcanic Ash is a Threat to Aircraft Safety | Volcanic Ash UPSC Prelims Topic

Context

• Hayli Gubbi volcano, northern Ethiopia erupted on 23 November after ~12,000 years.
• Sent ash plumes up to ~14 km into the sky.
• Ash cloud travelled across the Red Sea and Arabian Peninsula and even reached India’s western border.
• DGCA issued an advisory to airlines to steer clear of affected altitudes/areas.

How Volcanic Ash Impacts Aircraft — Step by Step

1. Ash enters jet engine
   • Engine sucks in air + ash instead of clean air.
   
2. Melting inside engine
   • Inside temperature: ~1,400–1,600°C.
   • Ash (fine rock/glass) melts and becomes a glassy liquid.
   
3. Deposits on hot parts
   • Melted ash sticks to turbine blades and other hot components.
   
4. Blocks cooling & airflow
   • Forms a glassy coating, blocking tiny cooling holes.
   • Chokes airflow inside the engine.
   
5. Engine damage/shutdown
   • Causes overheating, loss of power, compressor stall.
   • Engine can lose thrust or completely shut down.
   

Other effects on aircraft
• Ash abrades windscreens → poor visibility.
• Can clog sensors and contaminate cabin/air filters.