Context:
Following the eruption of the Hayli Gubbi volcano in northern Ethiopia on November 23, the Director General of Civil Aviation (DGCA) has issued advisories urging airlines to avoid affected airspaces. The volcanic plume travelled across India’s western border and beyond, raising concerns about flight safety and engine performance.
Key Highlights
- How Did the Ash Travel?
- The eruption sent thick plumes up to 14 km into the sky, carried eastward by strong winds.
- The ash cloud reached India’s western border on November 24 at 5:00 PM.
- It later moved across Rajasthan, Gujarat, Delhi-NCR, Punjab, Uttar Pradesh, and travelled further toward China.
- The plume shifted at altitudes ranging 15,000–25,000 feet, posing risks to cruising aircraft.
- How Does Ash Affect Aircraft?
- Aircraft engines operate at 1,600°C, far above the melting point of ash particles.
- When volcanic ash enters engines:
- It melts, flows toward cooler sections, and re-solidifies as glassy deposits.
- This blocks airflow, damages turbine blades, and leads to loss of thrust.
- It can also contaminate fuel, scratch cockpit windows, and damage sensors.
- Ash can cause engines to lose power or shut down completely.
- DGCA Advisory
- DGCA urged airlines to:
- Avoid affected regions and conduct safety risk assessments.
- Perform precautionary checks after flights from Oman, Dubai, Doha, and Jeddah.
- Re-route flights if visibility or engine performance may be compromised.
- Based on global protocols, aerosol-rich regions require no-fly zones or restricted operations.
- Impact on Flights
- Indian airlines cancelled several flights, especially those originating from West Asia.
- Some long-haul international flights were re-routed to avoid the ash cloud.
Relevant Prelims Points:
- Volcanic Ash Composition: Tiny particles of glass, rock, and sulphur compounds; highly abrasive.
- Engines & Melting Point Dynamics:
- Jet engines: ~1,400–1,600°C
- Volcanic ash melts at ~1,100°C → re-solidifies in cooler sections → blocks airflow
- Visibility Hazard: Ash clouds are difficult to detect on radar.
- Historic Incidents:
- 1982 British Airways Flight 9: All four engines failed due to ash from Mount Galunggung; engines restarted after descent.
- 1989 KLM Flight 867: All four engines failed after volcanic ash encounter over Alaska; aircraft recovered but engines were scrapped.
- Flight Levels: Commercial jets cruise at 30,000–40,000 feet — a common altitude for volcanic ash clouds.
Relevant Mains Points:
- Aviation Safety Regulation:
- DGCA follows ICAO volcanic ash contingency guidelines.
- Use of Volcanic Ash Advisory Centres (VAACs) for global monitoring.
- Environmental Science Linkages:
- Volcanic plumes travel long distances via jet streams.
- Ash affects climate, air quality, and atmospheric chemistry.
- Disaster Management (NDMA/ICAO norms):
- Crises require rapid airspace closures, re-routing, and risk assessment.
- Economic Impact:
- Flight cancellation costs, engine damage, operational delays.
- Tourism and international trade disruptions when major airports are affected.
- Way Forward:
- Improved satellite-based ash detection.
- International airspace coordination for faster alerts.
- Enhanced training for pilots on ash-encounter recovery.
- Developing more ash-resistant engine materials.