Volcanic ash and aviation emergencies


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Volcanic ash and aviation emergencies

  1. 1. Volcanic Ash Emergency in Europe Prof. David Alexander CESPRO - University of Florence
  2. 2. The problem
  3. 3. Volcanic Ash Aviation Hazard • from 1935 to 2003 102 aircraft encountered significant concentrations of volcanic ash • ash is not detectable by weather radar as it is dry • ash can reach cruise altitudes in five minutes • stratospheric ash concentrations may remain at circa 20,000 metres.
  4. 4. SEVERITY OF ENCOUNTER Class 0: acrid odour, electrostatic discharge 1: light cabin dust, EGT fluctuations 2: 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 restart 5: engine failure or other damage leading to crash No class 5 encounters have occurred so far.
  5. 5. Volcanic ash on jet engine turbine blades
  6. 6. Level 4 incidents KLM Asia Boeing 747 PH-BFC BA Boeing 747 G-BDXH
  7. 7. BA Flight 9 London to Auckland: 24-6-1982 • 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 made difficult by windscreen damage.
  8. 8. KLM Flight 867, Amsterdam-Tokyo 15 December 1989 • eruption of Redoubt Volcano, Anchorage, Alaska • all four engines failed leaving only critical systems on backup electrical power • battery loading caused temporary blanking of flight instruments as attempts made to restart engines • $80 million damage, all four engines written off.
  9. 9. What is the safe level of volcanic ash concentration in the stratosphere for commercial aviation flights?
  10. 10. The case of Eyjafjallajökull, April 2010
  11. 11. Source: UCL-IRDR Report
  12. 12. 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.
  13. 13. Eyjafjallajökull
  14. 14. Eyjafjallajökull eruption sequence
  15. 15. Problems • the safe level had never been established • the general circulation is dynamic • many forms of remote sensing do not give accurate readings of ash conc. • main risks ascending and descending through ash strata in upper troposphere and lower stratosphere • 'safe corridors' could close before flights along them can be completed.
  16. 16. Surveillance and warning International Civil Aviation Organisation (ICAO) Internat'l Airways Volcano Watch (IAVW) London IAVW: for UK, Iceland and N.E. N Atlantic Ocean Meteorological Watch Offices (MWOs) issue significant met. information (SIGMET) National Air Traffic Control Services (NATS)
  17. 17. Aviation hazard warning levels
  18. 18. 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 mile buffer area around black zone. On 17 May: creation of 'flyable' grey zone (2000-4000 μgm-3)
  19. 19. "The ALARP* level is only reached when the time, effort and cost of further reduction measures become disproportionate to the additional risk reduction obtained. The original values that defined the ALARP upper and lower limits in this case, viz. 2000 μgm-3 and 200 μgm-3 are ad hoc and without scientific basis and were generated by a Met Office program that was designed designed for entirely different purposes. *ALARP: As Low As Reasonably Possible
  20. 20. The ALARP concept Unacceptable risk Unacceptable region ALARP or tolerability region: risk assumed only if benefit warrants it Broadly acceptable region (no need for detailed work to demonstrate ALARP) Negligible risk
  21. 21. Reactions I was here for 9 days!
  22. 22. Reactions • was it right to ban all flights? • slow response with four-day delay • response was country level more than Europe-wide.
  23. 23. UK Cabined Office Briefing Room (COBR) convened Monday 19 April: travel emergency began at 12:00 Thursday 15 April
  24. 24. Volcanic ash was not in the UK Government's risk register
  25. 25. Hard times for the travelling public • 6.8 million travellers stranded • max stranding about 3 weeks (in Asia and Latin America) • bone marrow for transplants delayed • lack of interconnectedness of different transportation modes • UNNECESSARY RISK AVERSION?
  26. 26. "The havoc arising from the eruption of Eyjafjallajökull has been presented in many circles as being a consequence of the event being both unprecedented and unexpected – neither is the case."
  27. 27. Possible future scenario • much larger, longer eruption (Katla? - last erupted 1918) • civil aviation shut down for months ... or years ...? • need to integrate alternative transport modes for mass transit • need to integrate European emergency decision-making.
  28. 28. Volcanic emergencies are not totally predictable, can last a very long time, may be very expensive and can cause enormous disrpution (as well as major effects on weather and climate).
  29. 29. Did planes or the volcano emit the most CO2? European aviation Eyjafjallajökull industry: volcano: 344,109 150,000 tonnes tonnes Figures per day 206,465 tonnes CO2 saved by cancelling flights across Europe
  30. 30. d.alexander@alice.it www.emergency-planning.blogspot.com