A large number of flights to and from Ben Gurion airport in Tel Aviv continued to be disrupted Tuesday, as a large portion of European airspace, especially the airspace over Britain, remained closed to all airline traffic as a result of the eruption of the Eyjafjallajoekull volcano in Iceland last week. Several Israeli airlines scheduled extra flights over the weekend to several southern European destinations in order to help stranded Israeli citizens make it home for the Independence Day celebrations. The airlines had succeeded in securing arrangements for their passengers to travel overland from northern European points in order to connect with the additional flights added from southern Europe points.

Flights to and from the north of Europe remained problematic early this week, however, as the volcanic ash continued to plume sporadically skyward and to splay out across large portions of Britain and the continent. Flights to and from North America from Southern Europe and from Israel operated, though frequently delayed, by rerouting across southern Spain and the mid-Atlantic rather than through the shorter, more normal flight path across Eastern and Northern Europe, allowing the flights to avoid the closed airspace.
European aviation authorities reported that as of late Tuesday over 95,000 flights had been cancelled, leaving millions of passengers stranded, with the airline industry losing over $250 million (U.S) in revenue per day and the world economy suffering losses of billions of dollars.

The worst disruption in air travel since World War II caught almost everyone by surprise—not since World War II has British airspace been totally closed to all traffic.  Even while North American airspace was totally closed in 2001 after 9/11, British airspace still remained open.  SAS announced late Saturday that it is planning to initiate temporary lay-offs of its ground workers, pending the resumption of flights.  If the disruption continues as expected, other airlines will have no choice but to do the same.

A reduction in volcanic ash over the past few days has not resulted in a concomitant reduction in adverse atmosphere within the airports, however, as passengers’ frustrations continued and as tempers flared, with frequent confrontations between stranded passengers and airline staff who frequently appeared ill-equipped or utterly helpless to assuage the legitimate concerns of those in distress.

Why is the impact on the industry so severe and so sudden? Essentially, there are two reasons: the  location and the intensity of the volcanic eruption. Although on any given day there are as many as ten active volcanoes spewing volcanic ash into the air throughout the world, air traffic is rarely so disrupted because the volcanoes are neither erupting violently, nor are they located upwind of major concentrations of populations.  The Iceland volcano suffers neither impediment.  In addition to violently lifting billions of miniscule particles of glass and  igneous rock high into the atmosphere to precisely the altitudes at which most long-haul aircraft operate, the volcano is situated near the core of the upper atmosphere Atlantic jet stream that carries and splays out those corrosive particles directly across one of the world’s most densely populated regions.

Why Is Volcanic Ash So Dangerous To Aircraft? When volcanic ash is observed through a microscope, it is seen to be composed of microscopic shards of broken glass, usually mixed with miniscule pieces of igneous rock.  Although different volcanoes produce different mixtures and forms of the glass-rock combination, the impact on collision of these particles with modern jet aircraft is essentially the same. The particles that strike the exterior of the aircraft act like a huge sandblasting machine, rendering the aircraft skin and windows surfaces the same texture as a shower door, totally obscuring forward vision. Particles ingested into the aircraft’s air conditioning system are trapped by the air conditioning filters, blocking off air flow altogether, resulting in a stifling smell in the aircraft cabin.

Volcanic glass shards retrieved from the Yellowstone Caldera. Source: U.S. Dept. of the Interior

More importantly, when the volcanic ash particles are ingested by the jet engines they are heated in the combustion chamber of the engines, causing the glass particles to melt and fuse together, forming blobs of molten glass that then adhere to the compressor blades inside the core of the engines. These accumulations choke off the engines’ air flow, causing an immediate overheating of the engines, followed within seconds by total engine failure.

Eruption of Italy’s Mt. Etna, December 7, 2002 as seen from Flight 084, Toronto to Tel Aviv.

Because both or all of the aircraft’s engines ingest the particles at the same time, both or all engines are susceptible to total failure within minutes of the aircraft entering the volcanic ash cloud.  In fact, this is precisely what happened to British Airways Flight 009 on June 24, 1982, a Boeing 747 en-route on a scheduled flight between Kuala Lumpur and Perth, Australia. The aircraft unknowingly entered a volcanic ash cloud from the eruption of Mt. Galunggung. The flight was operating at night, and because aircraft weather radar does not detect microscopic ash particles, the flight crew had no advance warning of the ash cloud’s presence.  Within an estimated two minutes of entering the cloud, one of the engines failed.  One minute later, a second engine failed.  Then less than one minute later the remaining two engines failed, putting the aircraft into a 3,000 foot per minute powerless descent over the Indian ocean.

At approximately 13,000 feet above sea level the crew managed to restart one of the engines, then, another, and finally the remaining two.  Still, one of the engines continued surging and had to be shut down for a second time.  The crew made an emergency landing in Jakarta, though the landing had to be made entirely “on instruments” as the forward windscreens had been totally obscured by the sandblast effect of the volcanic ash.

Nineteen days later, a Singapore Boeing 747 flying through the very same airspace experienced the failure of three of its four engines for the very same reason.

In the past 30 years, more than 90 jet-powered commercial airplanes have encountered clouds of volcanic ash and suffered damage as a result.  With recent improvements in satellite imagery and ground-based volcanic ash reporting systems combined with an International Civil Aviation Organization program to monitor and disseminate information on volcanic activity, avoidance of the dangerous clouds by large commercial aircraft is becoming much more feasible.

Avoidance Is The Only Practical Solution

Despite the immensely adverse consequences of shutting down a huge swath of European airspace, so long as the volcanic ash cloud continues to spill over the European continent, the governments and the airlines have few options but to sit out nature’s events.  Limited flight operations may be possible, especially during the day when the ash cloud can be spotted visually and described accurately in terms of altitude and azimuth, however with varying upper wind patterns, the reliability of avoidance is highly susceptible to error.  The conflict between the need to end the economic disruption, as seen by airline industry executives, and the need to ensure the absolute safety of the flights, as seen by the world’s airline pilots, is one that grows in prominences as the adverse forces of nature slowly abate.  On Tuesday, for example, while the European airlines executives were pleading with the European governments to ease the flight restrictions, the European Airline Pilots Association, representing some 40,000 pilots, were urging further caution instead.

Volcanologists in Iceland have expressed a great deal of uncertainty as to how long this eruption will continue, although some relief is forecast for later in the week, as the ash plume lowers in altitude and intensity. Management of the airspace is now being handled in sectors, both vertically and horizontally, with many areas, especially those further south and east, unrestricted.  However, if the volcano should regain its vigour, sporadically spewing ash up to 30,000 feet above sea level, the North Atlantic and European air travel system will suffer a repeat of this past week .

Raymond Hall is a recently-retired Air Canada Captain who has operated over 200 flights between Canada and Israel.