Ash Cloud Update

This article is taken from IBT Traveller, and gives a reasonable summary of how the Mount Puyehue volcano has been affecting Australian airlines.

The Volcanic Ash Cloud Menace: To Fly or not to fly?

Mount Puyehue, Chile

I. FLIGHTS RESUME.  A week after ash clouds cancelled flights in Australia and New Zealand, flights are returning normal as the ash clouds have moved away.  Australia's Qantas resumed domestic flights resumed June 16.  Jetstar, Virgin Australia, and Air New Zealand have also restarted flights.  The ash clouds reached South Africa on Saturday, and South African Airways promptly suspended flights.

II. 7,000 MILES AWAY.  The ash clouds were spewed by Mount Puyehue volcano at the Cordon Caulle in the Andes mountains in Southern Chile, which is 7,000 miles or 11,300 kilometres from Australia.  After 51 years of inactivity, the volcano erupted June 4, sending an ash cloud towering up to 20 miles (30 km).  Chilean authorities evacuated 3,500 people but some have already returned to their homes.  Chilean geologists predict the volcano will be less active in the next two weeks. 

Ash plume spreading from the volcano

III. TO FLY OR NOT TO FLY.  Australian aviation authorities acknowledged that the ash clouds are a significant threat to aircraft, particularly jet engines, but said it was safe to fly around or under the plum.  Authorities left the decision making  -- whether to fly or not fly -- to the airlines or their operators.Qantas acknowledged there was insufficient equipment in Australia to measure volcanic ash density and hence, when in doubt, it opted to cancel flights. 

IV. FLAME OUT.  Australia's Bureau of Meteorology said ash melting in the hot section of the engine, and then fusing into a glass-like coating on components further back in the engine can cause loss of thrust and possible "flame out" or engine failure.  Other risks include windscreens becoming opaque, contamination of cabin air and hydraulic systems and erosion of aircraft parts, according to Qantas chief executive Alan Joyce.  About 30 years ago, a British Airways 747 suffered severe damage and had all four engines flame out upon encountering ash from Mt. Galunggung in Indonesia though it was able to make an emergency landing in Jakarta.

V. WRATH OF NATURE COSTLY.  Qantas cancelled about 350 flights and disrupting 40,000 passengers as a result of the week-long ash cloud problem.  It said the vast majority of the backlog had already been cleared.  It's even worse in Chile's neighbor Argentina -- not only flights were affected, some regions declared an economic emergency as falling ash is endangering sheep and other livestock and keeping tourists away at a time when winter season is starting.

VI. ASH CLOUDS DO A MAGELLAN.  Airservices Australia says it is not unprecedented for a volcanic ash cloud to circumnavigate the globe.  For example, in 1991 the volcano Cerro Hudson in Chile erupted and ash was transported twice around the world in two weeks, and was observed over south-east Australia a few days after the eruption.  In April last year, the eruption of another Icelandic volcano, Eyjafjallajokull, led to 100,000 canceled flights, affecting 10 million people at a cost of $1.7 billion.

VII. HOME SWEET HOME.  While the cloud disrupted flights in Argentina, Brazil and Uruguay, Chile has largely been spared and domestic flights were only cancelled June 17, the first time since the volcano erupting June 4.  Chile Civil Aviation Office chief Pablo Ortega said the tip of the cloud that has "traveled around the world" for thirteen days is now in front of Coyhaique, which is 800 kilometers (500 miles) south of the volcano.

VIII. COULD BE MONTHS.  Experts say fine ash particles from the Mount Puyehue volcano could potentially continue to affect air travel for months.  For instance, Qantas said that while it has resumed flights to and from Melbourne volcanic ash cloud could close airspace again on Tuesday afternoon (June 21).  Australia may see the ash cloud back on its second circuit of the globe.

IX. CALM BEFORE STORM.  The National Service of Geology and Mining in Chile said that in the coming days either (i) lava will flow out, indicating the eruption is nearing its end, or (ii) there will be a new explosion due to a build-up of magma below the surface.  The agency's director, after flying over the volcano, said it looked very similar to the 1960 eruption, which lasted for two months.

X. THOUSANDS OF OTHERS IN CHILE.  Chile's has 2,000 volcanoes, world's second-largest after Indonesia's.  About 50 to 60 are on record as having erupted, and 500 are potentially active.  Chile's Chaiten volcano erupted in 2008 and spewed molten rock and a vast cloud of ash that reached the stratosphere.  Chilean volcanoes are said to spew more ash than European volcanoes like Iceland's.  Not only that, the Calbuco volcano lies on the same fault as the Puyehue, and both are known to erupt within a few years of each other or together, according to Volcano Live.

Volcanoes in Chile - image from suehandel.wordpress.com

View the original article here.