Ash billows from the eruption of the long-dormant Hayli Gubbi Volcano in Ethiopia’s Afar region, on November 23.
| Photo Credit: AP
The story so far: Last week, the Director General of Civil Aviation (DGCA), India’s aviation regulator, ordered airlines to brace for the impact of volcanic ash travelling from Ethiopia after volcano Hayli Gubbi erupted for the first time in 12,000 years.
How did it travel?
Hayli Gubbi volcano in northern Ethiopia erupted on November 23 for the first time in nearly 12,000 years, sending thick plumes of ash up to 14 km into the sky, and across the Red Sea towards Yemen and Oman. It even drifted towards Iran. The volcanic ash reached India’s western border on November 24 at 5.50pm and moved out of the country’s airspace by 10.30pm on November 25. Moving at around 100-120 km/hour at an altitude of 15,000 to 25,000 feet the plume carried volcanic ash, sulphur dioxide and tiny particles of glass and rock, travelling over Rajasthan, parts of Gujarat, Delhi-NCR, Punjab and Uttar Pradesh before crossing over to China.
How does it impact aircraft?
A jet engine works by sucking in air, squeezing it, mixing it with fuel, burning it, and pushing hot gases out the back to produce thrust.
The engine runs extremely hot at temperatures of 1,600 degrees Celsius while turning very fast, with air racing through it at 600 mph. When volcanic ash gets into this environment, the silicate components melt and re-solidify at high temperatures creating a glassy deposit on hot parts, which blocks tiny cooling holes choking off flow within the engine. This can lead to engines losing power or shutting down.
What did the DCGA order state?
The DGCA issued an advisory urging airlines to steer clear of affected altitudes and regions to ensure safety. Airlines were also advised to report any suspected impact of ash on engine performance or cabin smoke or odour. Airports were ordered to inspect runways for contamination and suspend or restrict flight operations, if need be.
Air India cancelled at least nine flights on November 24 and 25, including those originating from Dubai, Doha and Dammam and said it was carrying out precautionary checks on aircraft.
Akasa also cancelled flights to and from Jeddah, Kuwait and Abu Dhabi.
How have flights been affected?
In 1982, a British Airways Boeing 747 flying at 37,000 ft enroute from London to Auckland flew through a volcanic ash cloud from Mount Galunggung near Jakarta. All four engines failed one after another due to the ash. As engines control the pressurisation system, the oxygen levels in the passenger cabin started to drop and passenger oxygen masks were deployed. With mountains blocking the way to the emergency airport, it seemed like the plane would have to ditch in the Indian Ocean. Luckily, after descending more than 25,000 feet, the pilots managed to restart one engine and then the other three, although one engine had to be shut down again. With enough power to reach the airport safely, the crew still faced the difficult task of landing with windscreens clouded almost completely by volcanic ash.
In 1989, a KLM Boeing 747-400 flying to Anchorage, Alaska, hit ash from the nearby Mount Redoubt eruption. All four engines shut down suddenly at 24,000 ft. The crew descended 14,000 ft and had to perform the engine restart procedure a number of times before it was able to successfully land the plane safely. But the engines worth $80 million were severely damaged and had to be scrapped.
Published – December 04, 2025 08:30 am IST
