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Prof. David AlexanderCESPRO - University of Florence
Volcanic AshEmergency in Europe
The problem
• from 1935 to 2003 102 aircraftencountered significantconcentrations of volcanic ash
• ash is not detectable byweather radar as it is dry
• ash can reach cruisealtitudes in five minutes
• stratospheric ash concentrationsmay remain at circa 20,000 metres.
Volcanic Ash Aviation Hazard
SEVERITY OF ENCOUNTERClass0: acrid odour, electrostatic discharge 1: light cabin dust, EGT fluctuations2: heavy cabin dust, external and internal
abrasion damage, window frosting,3: engine vibration, erroneous instrument
readings, hydraulic-fluid contamination,damage to engine and electrical system
4: engine failure requiring in-flight restart5: engine failure or other
damage leading to crashNo class 5 encounters have occurred so far.
Volcanicash onjet engineturbineblades
Level 4 incidents
BA Boeing 747 G-BDXH
KLM Asia Boeing 747PH-BFC
• Mount Galunggung, Indonesia
• four engines surged and flamed out
• 12-minute gliding time, 7000 m descent
• no. 2 engine failed again at 4000 m
• landing madedifficult bywindscreen damage.
BA Flight 9 London to Auckland: 24-6-1982
• eruption of RedoubtVolcano, Anchorage, Alaska
• all four engines failed leaving only criticalsystems on backup electrical power
• battery loading caused temporaryblanking of flight instruments asattempts made to restart engines
• $80 million damage,all four engines written off.
KLM Flight 867, Amsterdam-Tokyo15 December 1989
What is the safe level of volcanicash concentration in the stratosphere
for commercial aviation flights?
The case of Eyjafjallajökull, April 2010
Source: UCL-IRDR Report
Eyjafjallajökull eruption of 1821-3:• started 19-12-1821, ended 1-1-1823• central vent, subglacial explosive eruption• volcanic explosivity index VEI=2• 4 million m3 of tephra emitted
Eyjafjallajökull eruption of Apr-May 2010:• started 20-3-2010, ended(?) 21-5-2010• VEI 2-3• vulcanian eruption style• maximum plume height 13 km• ash had 58% silica concentration.
Eyjafjallajökull
Eyjafjallajökulleruptionsequence
• the safe level had never been established
• the general circulation is dynamic
• many forms of remote sensing do notgive accurate readings of ash conc.
• main risks ascending and descendingthrough ash strata in uppertroposphere and lower stratosphere
• 'safe corridors' could close beforeflights along them can be completed.
Problems
International Civil Aviation Organisation(ICAO)
Internat'l Airways Volcano Watch (IAVW)
London IAVW: for UK, Icelandand N.E. N Atlantic Ocean
Meteorological Watch Offices (MWOs)issue significant met. information(SIGMET)
National Air Traffic Control Services(NATS)
Surveillance and warning
Aviation hazard warning levels
On 20 April 2010:-• No Risk: below 200 μgm-3
• Enhanced Procedures Zone (EPZ)(Red Zone): 200 μgm-3 to 2000 μgm-3
• No Fly Zone (NFZ) (Black Zone):above 2000 μgm-3
On 11 May: removal of 60 nautical milebuffer area around black zone.
On 17 May: creationof 'flyable' grey zone(2000-4000 μgm-3)
"The ALARP* level is only reached when thetime, effort and cost of further reductionmeasures become disproportionate to theadditional risk reduction obtained. Theoriginal values that defined the ALARPupper and lower limits in this case, viz.
2000 μgm-3 and 200 μgm-3 are ad hoc andwithout scientific basis and were generatedby a Met Office program that was designeddesigned for entirely different purposes.
*ALARP: As Low As Reasonably Possible
The ALARP concept
Negligible risk
Unacceptable risk
Broadly acceptableregion (no need fordetailed work todemonstrate ALARP)
Unacceptable region
ALARP or tolerabilityregion: risk assumedonly if benefit warrants it
Reactions
I was here
for 9 days!
Reactions
• was it right to ban all flights?
• slow response with four-day delay
• response was country levelmore than Europe-wide.
UK Cabined OfficeBriefing Room(COBR) convenedMonday 19 April:travel emergencybegan at 12:00Thursday 15 April
Volcanic ash wasnot in the UKGovernment'srisk register
• 6.8 million travellers stranded
• max stranding about 3 weeks(in Asia and Latin America)
• bone marrow for transplants delayed
• lack of interconnectedness ofdifferent transportation modes
• UNNECESSARY RISK AVERSION?
Hard times for the travelling public
"The havoc arising from the eruptionof Eyjafjallajökull has been presentedin many circles as being a consequenceof the event being both unprecedentedand unexpected – neither is the case."
• much larger, longer eruption(Katla? - last erupted 1918)
• civil aviation shut down for months... or years ...?
• need to integrate alternativetransport modes for mass transit
• need to integrate Europeanemergency decision-making.
Possible future scenario
Volcanic emergencies are not totallypredictable, can last a very long time,may be very expensive and can causeenormous disrpution (as well as major
effects on weather and climate).
European aviationindustry:344,109tonnes
Eyjafjallajökullvolcano:
150,000 tonnes
206,465 tonnes CO2 saved bycancelling flights across Europe
Did planes or the volcano emit the most CO2?
Figuresper day
