How does volcanic ash affect air travel?
More than 80 commercial aircraft have unexpectedly encountered volcanic ash in flight and at airports in the past 15 years. Seven of these encounters caused in-flight loss of jet engine power, which nearly resulted in the crash of the airplane. A range of damage may occur to airplanes that fly through an eruption cloud depending on the concentration of volcanic ash and gas aerosols in the cloud, the length of time the aircraft actually spends in the cloud, and the actions taken by the pilots to exit the cloud.Ash ingested by jet engines may lead to the immediate deterioration in engine performance and engine failure.
The principal cause of engine failure is the deposition of ash in the hot sections of the engine. Glass from melting volcanic ash will coat fuel nozzles, the combustor, and turbine, which reduces the efficiency of fuel mixing and restricts air passing through the engine. This causes surging, flame out, and immediate loss of engine thrust. Ash may also seriously erode moving engine parts, including the compressor and turbine blades, which reduces the efficiency of the engine.
Air that enters an airplane's interior first passes through the engines. Some ash particles ingested through the engines will travel through the plane's ventilation ductwork throughout the plane. The ash may clog air-filter systems and spread throughout the cabin, contaminating cabin fixtures, carpeting, seat covers, and cushions. The ash can also damage the plane's electronic system, including power generators and navigation instruments.
The principal cause of engine failure is the deposition of ash in the hot sections of the engine. Glass from melting volcanic ash will coat fuel nozzles, the combustor, and turbine, which reduces the efficiency of fuel mixing and restricts air passing through the engine. This causes surging, flame out, and immediate loss of engine thrust. Ash may also seriously erode moving engine parts, including the compressor and turbine blades, which reduces the efficiency of the engine.
Air that enters an airplane's interior first passes through the engines. Some ash particles ingested through the engines will travel through the plane's ventilation ductwork throughout the plane. The ash may clog air-filter systems and spread throughout the cabin, contaminating cabin fixtures, carpeting, seat covers, and cushions. The ash can also damage the plane's electronic system, including power generators and navigation instruments.
Catania's Airport
On 4 September 2007 a spectacular episode of lava fountaining occurred from the new vent on the east side of the Southeast Crater, also producing a plume of ash and scoriae which fell over the east flank of the volcano. A lava flow travelled about 4.5 km (2.8 mi) into the uninhabited Valle del Bove. This eruption was visible far into the plains of Sicily, ending the following morning between the hours of 5 to 7 am local time. Catania-Fontanarossa Airport shut down operations during the night for safety precautions.
Ash falling on airports will affect runways, taxiways and aprons, buildings, ground services, electrical utilities, communication facilities, and airplanes parked on the ground. Before these facilities and airplanes can return to normal service following an ash fall, the ash must be removed and cleaned from all surfaces, facilities, and airplanes.
Problems at airports include:
Problems at airports include:
- difficult landing conditions due to reduced runway friction coefficient, especially when the ash is wet,
- loss of local visibility when ash on the ground is disturbed by engine exhausts during take off and landing,
- deposition of ash on hangars and parked aircraft, with structural loading considerably worsened if weight is added by precipitation absorbed by ash, and
- contaminated ground-support systems.