Nothing can blow your travel plans like a volcano.
Case in point: the Kasatochi Volcano, which recently erupted in Alaska’s Aleutian Islands and blasted ash to altitudes of 50,000 feet, forcing Alaska Airlines to cancel 44 flights.
Earlier in the year, Chaiten volcano in Chile erupted and its plume of ash disrupted flights in the region for months.
Why is volcanic ash so dangerous to aircraft?
First of all, there are more volcanic eruptions than most of us realize and the plume of ash from an eruption can rise far into the atmosphere.
To make matters worse, the volcanic ash that can stop jet engines cold, is not detected or displayed on cockpit radars because of the small size of the ash particles and low reflectivity. Plus, it can be obscured by weather clouds, according to The National Oceanic & Atmospheric Administration (NOAA).
On average, 15 major explosive eruptions — those powerful enough to inject ash above 25,000 feet — occur each year. Ash plumes from a major eruption can affect aircraft thousands of miles downwind. For example, when Mt. St. Helens erupted in 1980, the plume reached an altitude of 90,000 feet in 30 minutes and was 50 miles wide.
NOAA operates two Volcanic Ash Advisory Centers – one in Anchorage , Alaska, and the other in Camp Springs , Md. These centers issue advisory statements, including graphics and text messages about the location and size of the ash clouds, which are distributed through several global networks and posted online in real-time. There is also a Volcanic Ash Forecast Transport and Dispersion model that projects the trajectory and location of the clouds at different altitudes on certain time scales.
According to the Air Line Pilots Association, nine Volcanic Activity Advisory Centers (VAACs) have been established worldwide to detect volcanic activity and disseminate information about it to the aviation community in a timely manner. Despite this important step having been taken, airlines have suffered significant financial losses caused by volcanic ash encounters in VAAC areas since their inception.
Volcanic ash is one of the most dangerous conditions that can be encountered in the air by aircraft. Airborne ash can diminish visibility, damage flight control systems, and cause jet engines to fail. A fact sheet published by the Air Line Pilots Association details the history of volcanic eruptions and their effects on aircraft in flight.
In 1982, a British Airways flight had one of the first jumbo jet incidents with volcanic ash.
On 24 June 1982, the route was flown by City of Edinburgh, a 747-236B registered G-BDXH. The aircraft flew into a cloud of volcanic ash thrown up by the eruption of Mount Galunggung, resulting in the failure of all four engines, although the reason for the failure was not then apparent to the crew or ground control. The aircraft was diverted to Jakarta in the hope that enough engines could be restarted to allow it to land there. The aircraft was able to glide far enough to exit the ash cloud, and all engines were restarted (although one failed again soon after), allowing the aircraft to land safely.
Then in 1989 a KLM flight from Amsterdam to Anchorage descended through another cloud of volcanic ash and also had all four engines stop. After descending 14,000 feet, the pilot managed to restart the engines and land the aircraft.
As the crew of KLM Flight 867 struggled to restart the plane’s engines, “smoke” and a strong odor of sulfur filled the cockpit and cabin. For five long minutes the powerless 747 jetliner, bound for Anchorage, Alaska, with 231 terrified passengers aboard, fell in silence toward the rugged, snow-covered Talkeetna Mountains (7,000 to 11,000 feet high).
All four engines had flamed out when the aircraft inadvertently entered a cloud of ash blown from erupting Redoubt Volcano, 150 miles away. The volcano had begun erupting 10 hours earlier on that morning of December 15, 1989.
Only after the crippled jet had dropped from an altitude of 27,900 feet to 13,300 feet (a fall of more than 2 miles) was the crew able to restart all engines and land the plane safely at Anchorage. The plane required $80 million in repairs, including the replacement of all four damaged engines.
After these two major near disasters, international governments created the Volcanic Ash Advisory Centers to monitor this particulate along flight paths. Alaska’s Aleutian Islands lie directly along one of the major North America to Asia aircraft corridors. The Philippines, where Mount Pinatubo erupted, lie at the center of one of Asia’s main flight routes. However, with warning, jets winging their way across these and other volcano affected routes can fly around the ash plumes.
The reality of volcano ash was brought home to travelers with the mass cancellations of Alaska Air flights in August 2008. And even today, flights in and out of sections of Argentina and Chile are affected by the remaining plume of ash from the eruption of the Chaiten volcano.
{ 1 trackback }
{ 1 comment… read it below or add one }
Thanks for the article Charlie. It brings back memories for me. I lived in Anchorage at the time of the KLM jet incident and we, like many others, were scheduled to fly out to the lower 48 that evening as that was the last day of school before Christmas break. Our flight was not cancelled because the plane was already in Anchorage and they wanted to get it out of town. It was very weird showing up at the airport and seeing every flight listed on the board as cancelled, except ours. People were standing around hoping they could get a seat on our flight. As we walked to the gate, we kept hearing announcements saying “All passengers to Fairbanks, all airlines, please proceed to gate B1 for the bus.” It was very solemn and sober on the plane as we boarded. And most of us on the plane were never more grateful to land safely than when we did that night in Seattle. We were the last flight out of Anchorage for 3 days.