Sinabung ash cancels 21 flights at Kualanamu International Airport

Disruption overview

A renewed eruption at Mount Sinabung disrupted travel through Kualanamu International Airport in Medan, canceling 21 flights in the first 24 hours and delaying or rescheduling others on both domestic and international services. The airport also suspended runway operations from 10:50 am to 12:45 pm local time on 1 September 2026 while ash levels were checked before flights resumed. Because the disruption was caused by a volcanic eruption outside the airline's control, cash compensation is usually unlikely. Airlines should still help with rebooking or refunds, and provide care if you're left waiting.

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Disruption details

Volcanic ash from Mount Sinabung canceled 21 flights at Kualanamu International Airport in Medan within the first 24 hours after the volcano resumed erupting on 31 August 2026. For passengers, this meant sudden changes to both domestic and international journeys, with other services also delayed or moved to later departure times.

The disruption affects multiple carriers using Kualanamu, even though no airlines have been named publicly. The first wave of cancellations came as airport and airline teams watched how the ash cloud was moving, and the total could still climb if conditions worsen or airlines decide to trim schedules again.

Passenger safety remains the priority, and travelers have been urged to check flight status through official airline channels before heading to the airport. In a fast-moving situation like this, a flight that looks on time can still be delayed, rescheduled, or canceled if ash drifts back over the airfield.

To protect operations, AirNav Indonesia issued NOTAM A3250/26 and temporarily closed the airport on 1 September 2026. Runway operations were suspended from 10:50 am to 12:45 pm local time while ash levels on the airfield and nearby flight paths were assessed.

The airport has since reopened, but that didn't end the disruption straight away. Airlines still had to work through knock-on delays and revised schedules after the temporary closure, and the airport operator, airlines, and AirNav are continuing to review conditions hour by hour.

Further ground stops are still possible if volcanic ash returns over the airport or if Mount Sinabung's activity intensifies. That means passengers traveling through Medan may continue to see last-minute timetable changes even after flights resumed.

Mount Sinabung is about 70 kilometers from Kualanamu and re-entered an eruptive phase on 31 August 2026, sending ash several kilometers into the atmosphere. Indonesia's Geological Agency has already raised the volcano's alert level and warned that larger eruptions are possible, while local authorities accelerate evacuations in nearby villages.

Because this disruption was caused by a volcanic eruption outside the airline's control, cash compensation under EC 261 is usually unlikely. But that doesn't mean you're without support.

If your flight has been canceled or heavily delayed, your airline should still help with rebooking or a refund. If you're left waiting at the airport, they should also provide care such as food and refreshments, and accommodation plus transport if you need to stay overnight. If you want to better understand what may apply to your trip, AirHelp's free flight checker is a simple place to start.

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