Out of the ashes

2 min read

Andrew Allcock argues that the recent volcanic ash-inspired air transport chaos highlights the critical nature of science, engineering and technology, offering an example that can be put to future good use

It's an ill wind that blows nobody any good, as the saying has it. So what 'good' can be extracted from the Icelandic volcano incident (I've called it that, so you don't have to read this – Eyjafjallajökull). The two things that jump out to me are weather simulation (technology) and the safe-fly limits for ash, as measured in parts per million, or some such, and as can be accommodated by jet engines (technology, again). Taking engine technology first, we know aero engines can stall when encountering volcanic ash. The most often cited example involved a British Airways flight that encountered an ash cloud over Indonesia in 1982. Its four engines suffered power loss and the plane lost significant altitude before the turbines could be restarted. The key safety issue is the potential for fine ash deposits to damage jet engines, which take in air to cool turbines – ash can clog ducts, and cause overheating and engine failure. In addition, glass particles in ash can melt and destroy rotating blades and other parts. But there was no established safe-fly limit, other than zero ash, that is. A report of 19 April revealed that detailed analysis of the Rolls-Royce RB211 engines on a British Airways Boeing 747 that flew through the European volcanic cloud indicated no deterioration in performance. Prior to that, German airlines Lufthansa and Air Berlin said the decision to close much of Europe's airspace was not based on proper testing, saying that their aircraft showed no signs of damage, too. A maximum ash level was subsequently agreed late on 20 April. A few days before that, simulation was under attack. "The decision to close the airspace was made exclusively as a result of data from a computer simulation at the Volcanic Ash Advisory Centre in London," Air Berlin chief executive Joachim Hunold bellowed, while Lufthansa spokesman Klaus Walter was equally unhappy: "Not one single weather balloon has been sent up to measure how much volcanic ash is in the air. The flight ban, made on the basis just of computer calculations, is resulting in billion-high losses for the economy ...... In future, we demand that reliable measurements are presented before a flying ban is imposed." Basically, simulation became prediction (and that is a whole other topic). In both cases, the actual measurement of conditions, together with verification tests, were seen as necessary to establish reality. This is science and engineering in action, in support of the application, verification or improvement of technology. The establishment of safe working limits, in the case of jet engine technology, and the verification of what you think might be true, in the case of weather simulation. In both cases, this will most certainly lead to technology improvements and/or better understanding of the limits of the application of technology. Perhaps this might be an example used to galvanise schoolchildren when discussing the impact/relevance/use of science, engineering and technology viz daily lives. Some will have experienced its effects first hand, after all. First published in Machinery, May 2010