ATW Daily News
Volcanic ash, invisible to weather radar, presents serious danger to aircraft
Monday April 19, 2010
There have been 90 incidents over the last 30 years in which aircraft have encountered volcanic ash, invisible to weather radar and totally undetectable at night, and several of the encounters created very dangerous situations.
Made up of pulverized rock and glass, the ash gets into virtually every aircraft system and can paralyze engines in minutes. The ash turns molten in a jet engine's combustion chamber and melds with moving parts like spray paint. It blasts cockpit windows, compromising visibility in seconds, and also clogs vital speed sensors, rendering an aircraft's flight computers almost useless. The deposits additionally coat the fuel system's temperature sensors, creating a false and lower temperature reading that causes the automatic monitoring system to pour in more fuel. This makes the engine dangerously hot, damaging the turbine and potentially leading to a shutdown.
The two most famous encounters with volcanic ash involved 747s, one a British Airways flight over Indonesia in 1982 en route to Perth from Kuala Lumpur and another involving a 1989 KLM flight en route from Amsterdam to Anchorage. In both cases, all of the engines failed and eventually were restarted at much lower altitudes but later were scrapped because of the damage. The KLM 747's environmental control system was replaced, its fuel tanks were cleaned and the hydraulic systems needed repair.
When Mt. St. Helens erupted in 1980, a 727 and a DC-8 encountered separate ash clouds. Both experienced damage to their windshields and several systems but both landed safely despite the damage.
The increased availability of satellites and the technology to transform satellite data into useful information have reduced the number of volcanic ash encounters. But extensive ash clouds, such as the one now hovering over Europe, still present an enormous challenge.
In 1991, Mount Pinatubo on the island of Luzon in the Philippines erupted just 90 km. northwest of Manila. Over the course of several eruptions, the volcano ejected 10 cu. km. of material, making it the second-biggest eruption of the 20th century. There were 20 volcanic ash encounters with aircraft. Despite the more advanced ability to predict where ash could be found, the wide extent of the ash cloud made it difficult to avoid.
The eruption of Mt. Popocatepetl in Mexico in 1997 and subsequent intermittent eruptions forced the Mexico City airport to close multiple times for up to 24 hr.
Scientists working with the University of Iceland suggest it is a distinct possibility that the Eyjafjallajokull volcano will continue to erupt on and off for months to come, as occurred during the last eruptive period in 1821-1823.
Made up of pulverized rock and glass, the ash gets into virtually every aircraft system and can paralyze engines in minutes. The ash turns molten in a jet engine's combustion chamber and melds with moving parts like spray paint. It blasts cockpit windows, compromising visibility in seconds, and also clogs vital speed sensors, rendering an aircraft's flight computers almost useless. The deposits additionally coat the fuel system's temperature sensors, creating a false and lower temperature reading that causes the automatic monitoring system to pour in more fuel. This makes the engine dangerously hot, damaging the turbine and potentially leading to a shutdown.
The two most famous encounters with volcanic ash involved 747s, one a British Airways flight over Indonesia in 1982 en route to Perth from Kuala Lumpur and another involving a 1989 KLM flight en route from Amsterdam to Anchorage. In both cases, all of the engines failed and eventually were restarted at much lower altitudes but later were scrapped because of the damage. The KLM 747's environmental control system was replaced, its fuel tanks were cleaned and the hydraulic systems needed repair.
When Mt. St. Helens erupted in 1980, a 727 and a DC-8 encountered separate ash clouds. Both experienced damage to their windshields and several systems but both landed safely despite the damage.
The increased availability of satellites and the technology to transform satellite data into useful information have reduced the number of volcanic ash encounters. But extensive ash clouds, such as the one now hovering over Europe, still present an enormous challenge.
In 1991, Mount Pinatubo on the island of Luzon in the Philippines erupted just 90 km. northwest of Manila. Over the course of several eruptions, the volcano ejected 10 cu. km. of material, making it the second-biggest eruption of the 20th century. There were 20 volcanic ash encounters with aircraft. Despite the more advanced ability to predict where ash could be found, the wide extent of the ash cloud made it difficult to avoid.
The eruption of Mt. Popocatepetl in Mexico in 1997 and subsequent intermittent eruptions forced the Mexico City airport to close multiple times for up to 24 hr.
Scientists working with the University of Iceland suggest it is a distinct possibility that the Eyjafjallajokull volcano will continue to erupt on and off for months to come, as occurred during the last eruptive period in 1821-1823.
by Geoffrey Thomas
European flights remain grounded; airlines question 'proportionality' of response
Monday April 19, 2010
Volcanic ash from last week's eruption in Iceland continues to cause dramatic disruption to air traffic in Europe, with many airlines cancelling services for a fifth consecutive day Monday owing to airspace closures but questioning whether EU governments and ATC providers are overreacting.
Severe restrictions on civil flights across most of northern and central Europe remained in place over the weekend. This included airspace over Austria, Belgium, Croatia, the Czech Republic, Denmark, Estonia, Finland, most of France, most of Germany, Hungary, Ireland, northern Italy, the Netherlands, Norway, Poland, Romania, Serbia, Slovenia, Slovakia, Sweden, Switzerland, Ukraine and the UK. In some areas, upper airspace was made available for limited flights. But rather than easing, the restrictions spread on Sunday: 11 airports in Spain closed as did Bulgarian airspace.
IATA's "initial and conservative" estimate of the financial impact on the airline industry is at least $200 million per day in lost revenue. It added that carriers will incur further costs for rerouting aircraft, maintaining parked aircraft at various airports and providing care for stranded passengers. Assn. of European Airlines said 63,000 flights were cancelled Thursday-Sunday.
AEA and Airports Council International-Europe yesterday jointly called for an "immediate reassessment of flight restrictions," asserting that nonpassenger test flights conducted by several European airlines "have revealed no irregularities at all." The organizations questioned the "proportionality of the flight restrictions currently imposed."
KLM and Lufthansa were among the carriers that performed test flights over the weekend. KLM operated one on Saturday and was scheduled to operate nine more yesterday. The technical inspection conducted after Saturday's 737-800 flight, which climbed to an altitude of 41,000 ft., "revealed that no problems had been encountered and that the quality of the atmosphere is in order," KLM said.
KLM President and CEO Peter Hartman estimated the combined financial impact of lost revenue and costs for stranded passengers at €5 million ($6.8 million)-€10 million daily. "This is rather dramatic," he told Dutch media. He confirmed that the carrier does not have insurance that covers this event.
SAS warned it would lay off up to 2,500 employees temporarily in Norway starting today if aircraft remain grounded. It later announced that nearly all of its flights would be cancelled today, though it did say "a few domestic flights" would operate in Norway.
Several European carriers, including Finnair and LH, grounded their entire fleets. Ryanair said yesterday it has cancelled all scheduled flights to/from the UK, Ireland, Denmark, Finland, Norway, Sweden, Belgium, the Netherlands, France, Germany, Poland and the Baltic States through at least 1 p.m. Wednesday.
Eurocontrol said there were 10,400 flights in European airspace Friday compared to 28,000 normally and approximately 5,000 Saturday compared to 22,000 on a normal Saturday.
The situation has forced airlines in North America and Asia to cancel a high percentage of their Europe-bound flights. The US Air Transport Assn. said US carriers cancelled 282 of 337 scheduled Saturday transatlantic flights. Meanwhile, hundreds of thousands of passengers were stranded at airports across Asia over the weekend as airlines in the region halted nearly all flights to Europe, though some to southern Europe were still operating. Qantas cancelled all of its European flights through at least Tuesday.
Severe restrictions on civil flights across most of northern and central Europe remained in place over the weekend. This included airspace over Austria, Belgium, Croatia, the Czech Republic, Denmark, Estonia, Finland, most of France, most of Germany, Hungary, Ireland, northern Italy, the Netherlands, Norway, Poland, Romania, Serbia, Slovenia, Slovakia, Sweden, Switzerland, Ukraine and the UK. In some areas, upper airspace was made available for limited flights. But rather than easing, the restrictions spread on Sunday: 11 airports in Spain closed as did Bulgarian airspace.
IATA's "initial and conservative" estimate of the financial impact on the airline industry is at least $200 million per day in lost revenue. It added that carriers will incur further costs for rerouting aircraft, maintaining parked aircraft at various airports and providing care for stranded passengers. Assn. of European Airlines said 63,000 flights were cancelled Thursday-Sunday.
AEA and Airports Council International-Europe yesterday jointly called for an "immediate reassessment of flight restrictions," asserting that nonpassenger test flights conducted by several European airlines "have revealed no irregularities at all." The organizations questioned the "proportionality of the flight restrictions currently imposed."
KLM and Lufthansa were among the carriers that performed test flights over the weekend. KLM operated one on Saturday and was scheduled to operate nine more yesterday. The technical inspection conducted after Saturday's 737-800 flight, which climbed to an altitude of 41,000 ft., "revealed that no problems had been encountered and that the quality of the atmosphere is in order," KLM said.
KLM President and CEO Peter Hartman estimated the combined financial impact of lost revenue and costs for stranded passengers at €5 million ($6.8 million)-€10 million daily. "This is rather dramatic," he told Dutch media. He confirmed that the carrier does not have insurance that covers this event.
SAS warned it would lay off up to 2,500 employees temporarily in Norway starting today if aircraft remain grounded. It later announced that nearly all of its flights would be cancelled today, though it did say "a few domestic flights" would operate in Norway.
Several European carriers, including Finnair and LH, grounded their entire fleets. Ryanair said yesterday it has cancelled all scheduled flights to/from the UK, Ireland, Denmark, Finland, Norway, Sweden, Belgium, the Netherlands, France, Germany, Poland and the Baltic States through at least 1 p.m. Wednesday.
Eurocontrol said there were 10,400 flights in European airspace Friday compared to 28,000 normally and approximately 5,000 Saturday compared to 22,000 on a normal Saturday.
The situation has forced airlines in North America and Asia to cancel a high percentage of their Europe-bound flights. The US Air Transport Assn. said US carriers cancelled 282 of 337 scheduled Saturday transatlantic flights. Meanwhile, hundreds of thousands of passengers were stranded at airports across Asia over the weekend as airlines in the region halted nearly all flights to Europe, though some to southern Europe were still operating. Qantas cancelled all of its European flights through at least Tuesday.
by Cathy Buyck and Aaron Karp
