Introduction
There are different modes of transport and we do not even think what dangers await us while traveling. Here are 5 reasons why airplane crash happens: 1. Pilot error; 2. Mechanical failure; 3. Weather; 4. Intentional crashes; 5. Volcanic ash cloud.
Let’s consider one of the events that affects air traffic.
Eyjafjallajokull is a strato volcano, also known as a composite volcano. The eruptions of Eyjafjallajökull caused enormous disruption to air travel across western and northern Europe over an initial period of six days in April 2010. In response to concerns that volcanic ash ejected during the 2010, eruptions of Eyjafjallajökull in Iceland would damage aircraft engines, the airspace control of many European countries considered to instrument flight rules traffic, resulting in the largest air-traffic shut-down since World War II. Volcanic ash is a great danger to jet planes. Particles get caught in the engines, turn hard and stop them. The closures caused millions of passengers to be stranded not only in Europe, but across the world. With large parts of European airspace closed to air traffic, many more countries were affected as flights to, from, and over Europe were cancelled. About 20 countries closed their airspace to commercial jet traffic and it affected approximately 10 million travellers. The eruption was declared officially over in October 2010, when snow on the glacier did not melt. [1, p.1]
Although no one died, everyone nearby had been evacuated safely ahead of the eruption. Gina Christie one of the residents that witnessed the eruption of the volcano, Eyjafjallajökull. «I woke up on Friday with a weird feeling that something just wasn’t right. It wasn’t light as it normally is — we don’t really have night-time at this time of year. I looked outside and there was a thick, black cloud of ash directly above us. It was exactly like the middle of winter. What is even more surreal was the absolute bright daylight on either side of our village.» Gina was in fact right, nothing was right and she was soon evacuated safety. Although it didn’t kill anyone, it was scientifically amazing. The ash plume stayed in the atmosphere for about a month. Also the ash ended up spreading unusually far. Also the magma had a reaction with the glacier water and turned it into ash.
Now, a new camera has been developed that will allow pilots to see and avoid volcanic dust clouds, making similar eruptions in the future much less disruptive.
Main points
What is volcanic ash?
Volcanic Ash is defined as very small solid particles ejected from a volcano during an eruption which have intermediate axes measuring 2 mm or less (US Geological Survey) and «fine ash» is further defined by the same source as particles smaller than 1/16 (0.0625) mm across.
Description of volcanic eruption
During a volcanic eruption, huge quantities of material can be ejected into the atmosphere, reaching great height and remaining a threat to aviation for several months. Volcanic ash accumulates at higher altitudes in clouds which then drift with the wind. The ash does not show up on aircraft weather radar or ATC radars because of the small size of the particles. Ash particles carry electrical charges and, within a cloud of volcanic ash, this can give rise to Thunder and Lightning in the area immediately overhead the eruption.
At night, St Elmo’s Fire, created when charged ash particles hit the aircraft, may be the first circumstantial indication to a flight crew that they are flying into dense volcanic ash. Other indications might be a sulphurous smell and dust within the cabin.
What effects does volcanic ash have on airplane?
Volcanic Ash encounter can result in engine damage and malfunction:
Engine Malfunction. The principal risk to continued safe flight, arising from flight through high concentrations of volcanic ash, is the melting within the engine of ash particles, which are predominantly composed of silicates with a melting point of 1100°C This melting point is considerably less than the core operating temperature of high by pass turbine engines which, at normal thrust settings, is at least 1400°C. Ingested silicate ash melts in the hot section of the engine and then fuses onto the high pressure turbine blades and guide vanes. This drastically reduces the throat area and both static burner and compressor discharge pressures rapidly increase and cause engine surge. Transient and possibly terminal loss of thrust can occur in the most severe cases with a successful engine re-start only possible if clear air can be regained. If present at sufficient densities, ash particles can also contribute to engine malfunction by simple deposition. In either case, the added debris clogs up the engine airflow and is likely to initially lead to engine surging and ultimately to a Flame Out. Reducing the thrust setting quickly to idle may lower the core temperature enough to prevent silicates melting.
Long Term Engine Damage. The abrasive effect of volcanic ash particle impact can cause surface roughness inside turbine engines which, whilst it will not affect their continued normal operation, will result in a reduced specific fuel consumption. It is impossible to repair such damage, so the life of an affected engine could be considerably reduced. [2, p.1-2]
External Surface Corrosion. Ash can cause significant damage to the exposed surface of the aircraft skin and to the outer ply of windscreens. If the ash encounter is severe, the latter may become sufficiently abraded to be difficult to see through. [2, p.1-2]
Researchers from the Norwegian Institute for Air Research have developed a device (AVOID) with which airline pilots can detect ash clouds and fly around them. Volcanic ash is a great danger to jet planes. Particles get caught in the engines, turn hard and stop them.
With the new device installed airline pilots will be able to see ash clouds up to 200 km ahead of them. The system uses infrared cameras that are on the wings of the plane. It can also measure how dense the clouds are and spot layers of clean air between them. Together with weatherdata a detailed 3D map of the surrounding airspace can be created. Pilots can monitor how ash clouds will spread and adjusttheir course . Up to now, scientists have only been able to see the ash clouds but not make out how dense they are.
The new device has already been tested in an Airbus flying around Europe’s most active volcano, Mount Etna in Sicily. British budget airlines Easyjet will be the first to use the new ash cloud detection. If it works properly other airlines will be soon to follow.
In Russia a method of monitoring the airspace has been developed in the zones of volcanic ash clouds distribution based on the use of specialized unmanned aerial vehicle (UAV).
The technical result of the proposed method is an increase in accuracy and reliability of emissions in airspace affected by clouds of volcanic ash, pollution areas in order to determine the flight zones (sections of air routes, airport areas), allowing, taking into account the meteorological situation, to safely operate air transport. The technical result is achieved by the fact that the method monitoring of airspace in volcanic ash cloud propagation zones determination of cloud location and current concentration value the eruptions are carried out using a UAV equipped with specialized measuring equipment that provides optimal collection volcanic cloud information, transmission of information to the monitoring point and control of UAVs to build a three-dimensional model of propagation in the atmosphere products of volcanic eruption in order to determine in the airspace of flight zones (sections of air routes), allowing the safe operation of air transport.
The UAV provides monitoring of at a distance from the control point of the order of hundreds (thousands) kilometers; the specialized research equipment of the UAV additionally includes equipment for remote detection of atmospheric pollution products (optical location systems), including LIDAR locators and passive IR sensors, equipment designed to determine the direction and speed of the wind in the studied part of the airspace for the development of predictive trajectories of displacement of volcanic ash clouds at different levels.
The proposed composition of UAV’s measuring equipment provides integration in a single system of all information collecting media about the volcanic ash cloud:
— automatic multi-component gas analyzer;
— radiometer;
— apparatus for remote detection of volcanic ash clouds in front of aircraft (optical location systems including LIDAR locators and passive IR sensors);
— dust monitoring instruments (dust meters) of different operating principle, providing rapid, repeated measurement of the current concentration value volcanic ash in the atmosphere;
— equipment for determining the current location of the aircraft (NAVSTAR and/or GLONASS);
— equipment for determining wind parameters (wind direction and speed) in point of the air space under study;
— equipment for transmitting measurement results in real time to the point UAV flight monitoring and control.
The use of the proposed method of monitoring airspace in volcanic ash cloud propagation zones improve the regularity and efficiency of air transport in regions with high volcanic activity . The economic efficiency of the proposed method is primarily determined by ensuring the safety of people in the process of monitoring the airspace through UAV’s research flights, covering all possible costs.
Conclusion
In areas of volcanic ash cloud propagation the use of AVOID and UAVs can improve the rhythmicality and efficiency of air transport in regions with high volcanic activity. But the device and the UAV have their drawbacks.
AVOID has some shortcomings:
– the system does not allow to provide targeted, safe monitoring for the crew of the atmosphere directly in the areas of volcanic plume propagation with instrumental determination of the concentration of volcanic eruption products to create an accurate three-dimensional model of volcanic ash distribution in the airspace;
– the system does not allow to create a detailed picture of air pollution by various products of volcanic eruption, including at different levels.
Shortcomings of using UAVs are:
— The duration, range and ceiling of the flight of the claimed class of UAVs do not allow monitoring of airspace areas affected by the volcanic plume.
— In the process of monitoring the atmosphere the obtained results are not compared with the maximum permissible concentration values of volcanic eruption products, which ensure trouble-free operation of aircraft, primarily equipped with turbojet engines.
— The absence of an algorithm of using data from artificial earth satellites and the results of forecasting the motion pattern and evolution of volcanic ash clouds at different levels to develop optimal routes and trajectories of airspace monitoring at the stage of preparation of the UAV’s research flight.
Despite the above disadvantages these methods can permit to preclude the beginning of aviation accidents and thus save the lives of many people in the world.
References:
- Weinzierl Physics and Chemistry of the Earth: 2012.
- Flight Safety and Volcanic Ash: First edition, 2012.
