Four eruptions in the modern jet age have grounded flights at scale — and the record shows no single rulebook governs the response. The biggest of them, Iceland’s Eyjafjallajökull in 2010, cancelled more than 100,000 flights.
What shifted after 2010 was the size of the shutdown. What hasn’t shifted is the decision itself: each airline still judges on its own whether to fly through a plume.
Your departure board can go dark on a cloudless morning. Volcanic ash doesn’t need to be visible overhead to shut an airport — it only needs to be forecast to drift across the approach path, or to have fallen on the runway overnight.
That physical fact is why ash is treated as a hard safety boundary rather than bad weather. But the industry’s answer to it has never been one answer. In 1989, a Boeing 747 flew into ash from Alaska’s Redoubt and lost all four engines mid-air; the crew restarted them and landed. Two decades later, Iceland’s Eyjafjallajökull didn’t kill a single engine — it grounded a continent.
This list covers four eruptions that forced the industry to react, and the decision-making gap they expose. Only events confirmed by official assessments made the cut.
At a glance
- Redoubt, 1989: the KLM 867 engine loss
- Redoubt, 2009: the Anchorage shutdown
- Pinatubo, 1991: the costliest ash bill
- Eyjafjallajökull, 2010: the airspace-wide closure
The eruptions that grounded flights
Four events made the verified record: two eruptions of the same Alaskan volcano twenty years apart, plus the two that bracket the shift from in-flight improvisation to airspace-wide shutdown.
| Date | Volcano/location | Airports closed or duration | Documented aviation impact | Economic cost | Regulatory era and carrier decision point | Status |
|---|---|---|---|---|---|---|
| December 15, 1989 | Redoubt, Alaska | Anchorage airport remained open immediately after the incident; no verified closure duration in the retrieved primary source | KLM Flight 867, a Boeing 747-400, lost power in all four engines in ash, restarted them, and landed safely | About US$80 million in aircraft damage; the 1989-90 eruption’s total estimated economic cost was US$160 million | Pre-2010 incident-management era; the aircraft crew encountered the plume and recovered in flight | Confirmed |
| March-April 2009 | Redoubt, Alaska | Ted Stevens Anchorage International Airport closed for 20 consecutive hours | Approximately 200 Alaska Airlines flights were cancelled; FedEx, UPS, and other cargo carriers rerouted to Seattle | Total 2009 impact was unavailable in the assessment; air-freight disruption was estimated at approximately US$20 million per day | Pre-2010 transition period; airport and carriers made operational cancellations and rerouting decisions in response to ashfall and forecasts | Confirmed |
| June 1991 | Pinatubo, Philippines | Clark Air Force Base permanently closed after approximately 175 mm of ashfall; no commercial-airport closure duration established | USGS reports damage to 16 aircraft flying during the eruption | US$700 million total eruption damage, including US$100 million to aircraft | Pre-2010 era; operators grounded or relocated aircraft as ash distribution remained difficult to predict | Confirmed |
| April 2010 | Eyjafjallajökull, Iceland and Europe | Progressive closure of much of European airspace over seven days | More than 100,000 flights cancelled; just under 30% of worldwide scheduled passenger capacity grounded | Airlines lost about US$400 million per day at the peak; AEA members lost just under €200 million overall | Post-2010 airspace-wide restriction era; authorities closed airspace proactively while airlines cancelled or rerouted services | Confirmed |
| Source: National Weather Service; U.S. Geological Survey; International Air Transport Association | ||||||
1. Redoubt, 1989: the KLM 867 engine loss
All four engines quit on a Boeing 747-400 descending into Anchorage on December 15, 1989.
KLM Flight 867 flew into ash from Redoubt and lost power across every engine. The crew restarted them and landed safely — but the jet took roughly US$80 million in damage, according to the National Weather Service assessment of the eruption.
That figure covers the aircraft alone. The wider 1989–90 Redoubt episode carried an estimated US$160 million in total economic cost. The distinction matters: one number is a repair bill, the other is what a volcano costs a region.
2. Redoubt, 2009: the Anchorage shutdown
Ted Stevens Anchorage International Airport stayed shut for 20 consecutive hours in March–April 2009.
This time the ash fell rather than drifted. Roughly 200 Alaska Airlines flights were cancelled, and FedEx, UPS and other cargo carriers rerouted through Seattle.
The freight hit ran about US$20 million a day. For a traveler, the lesson is that a closure can be triggered by ash on the ground, not just a plume in the flight path — which is why your flight can be grounded under a clear sky.
3. Pinatubo, 1991: the costliest ash bill
US$700 million in total damage, US$100 million of it to 16 aircraft.
Pinatubo’s June 1991 eruption buried Clark Air Force Base under roughly 175 millimeters of ash and closed it permanently. The USGS accounting of the eruption is the costliest in this list.
What it shows is how hard ash distribution was to predict in the pre-2010 era. Operators grounded or moved aircraft after the fact, reacting to where the ash had already gone rather than to a forecast.
4. Eyjafjallajökull, 2010: the airspace-wide closure
More than 100,000 flights cancelled and just under 30% of worldwide scheduled passenger capacity grounded.
Iceland’s April 2010 eruption didn’t kill an engine. It closed airspace — progressively, across much of Europe, over seven days — and that is the hinge this list turns on.
Airlines lost about US$400 million a day in scheduled-service revenue at the peak, per IATA. The Association of European Airlines put its members’ full-period losses at just under €200 million. Travelers caught in it were delayed an average of three and a half days and spent roughly NOK 9,000 extra on travel and accommodation.
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How we picked
Every event here is backed by an official assessment or an industry body’s own accounting — the National Weather Service for both Redoubt episodes, the USGS for Pinatubo, IATA and the Association of European Airlines for Eyjafjallajökull. Two eruptions the research flagged, Kelud 2014 and Sinabung, could not be confirmed against official or industry sources and were left out rather than padded in.
What this means for you
The practical takeaway isn’t geological. When ash disrupts your trip, the decision to fly or cancel sits with your airline — so the questions you ask matter more than the science.
Start with the waiver. Ask whether your carrier has issued one, whether it will rebook you on a partner airline, and what its rerouting policy covers. Waiver terms are policy-dependent; the research turned up no universal reimbursement rule.
Budget for a long wait, and keep receipts. Insurer payouts, government compensation, and a complete passenger-compensation total for either the 2009 or 2010 events didn’t surface in the public record — which means your airline’s own policy is the document that decides what you get back.
Reporting by
Key terms
- ICAO Document 9691
- ICAO Document 9691 is the Manual on Volcanic Ash, Radioactive Material and Toxic Chemical Clouds, the international reference on how aviation handles ash hazards. It is addressed to states and to the organizations taking part in the International Airways Volcano Watch, and it covers how ash clouds are detected and tracked, what they do to aircraft, and who is responsible for warnings. It is guidance rather than regulation, so it does not dictate any carrier’s flight decision.
- Annex 6
- Annex 6 is the ICAO standard covering how commercial air operators must run their operations. It requires operators to build appropriate volcanic-ash mitigation into the safety-management systems they have had approved. That duty sits with the operator rather than the regulator, which is why two airlines can read the same ash forecast and reach opposite decisions.
- Safety-management system
- A safety-management system is the formal framework an operator uses to identify hazards and control risk across its operations. Under ICAO Annex 6, operators must fold volcanic-ash mitigation into the safety-management system they have had approved. Because these systems are internal, no two carriers are guaranteed to handle the same ash forecast the same way.
- International Airways Volcano Watch
- The International Airways Volcano Watch is the international network that monitors volcanic ash and issues warnings to aviation. It brings together states and the organizations that take part in it, and ICAO’s Document 9691 is addressed to them. Its warnings feed the forecasts carriers rely on, but the go/no-go call still rests with each airline.
Questions? Answers.
Is there one shared rulebook that decides when airlines can fly through volcanic ash?
No. ICAO’s Document 9691 offers guidance to states and warning organizations rather than a binding rule, and Annex 6 places ash mitigation inside each operator’s own approved safety-management system. No consolidated public source listing major airlines’ complete go/no-go procedures was identified.
What happens to your money when volcanic ash cancels a flight?
The retrieved record doesn’t establish a universal rule. Insurer payouts, government compensation, and a complete passenger-compensation total weren’t identified for the documented eruptions, so what you recover depends on your airline’s own waiver and refund policy.
How long has an ash cloud actually kept an airport shut?
Ted Stevens Anchorage International Airport closed for 20 consecutive hours during the 2009 Redoubt eruption. Pinatubo’s 1991 ashfall buried Clark Air Force Base under roughly 175 millimeters and closed it permanently.
Has a commercial jetliner ever lost all four of its engines to volcanic ash?
Yes. KLM Flight 867 lost power in all four engines after flying into Redoubt ash on December 15, 1989, while descending toward Anchorage. The crew restarted the engines and landed safely, with damage reaching about US$80 million.
