Volcanic Ash Grounded Flights in Europe - Engine Moving Parts and Windshield Can Suffer Indentation

AIRCRAFT AVOID airspace that has volcanic ash as it can wreck the flight ability of propeller and jet aircraft. The ash is so fine that it will invade the spaces between rotating machinery and jam them – silica in ash melts at about 1,100 degrees and fuses to turbine blades and nozzle guide vanes (another part of the turbine assembly), which in modern aircraft operate at 1,400 degrees.

Aeronaves evitam espaço aéreo que tenha cinca vulcânica porque ela pode destruir a habilidade do voo de aeronave à hélice e à jato. A cinza é tão fina que ela invadirá os espaços entre as partes rotativas dos motores [Jet Engine Animation] e emperrá-las. Sílica [areia] na cinza derrete acerca de 590ºC e adere às palhetas da turbina e às alhetas guias de esguicho [de combustível para os queimadores], as quais operam em aeronaves modernas à temperatura de 760ºC.

That can be very dangerous – as the crew of two aircraft, including a British Airways Boeing 747, discovered in 1982 when they flew through an ash cloud from the Galunggung volcano in Indonesia.

Isso pode ser muito perigoso - quando a tripulação de duas aeronaves, incluindo um Boeing 747 da British Airways, descobriu em 1982 quando eles voaram através de uma nuvem de cinza do vulcão Galunggung na Indonésia.

All four engines on both planes stopped; they dived from 36,000ft to 12,000ft before they could restart the engines and make emergency landings.

Todos quatro motores em ambos aviões pararam. Eles mergulharam de 36.000 pés para 12.000 pés antes que eles pudessem reacender os motores e fazer pousos de emergência. [Os motores foram reacendidos]

That is not the only problem. Ash can pit the windscreens of the pilots cabin, damage the fuselage and light covers, and coat a plane so much that it becomes tail-heavy. At runways ash creates an extra problem as takeoffs and landings will throw it into the air again - where the engines can suck it in and it will cause major damage to moving parts.

Esse não é o problema único. Cinza pode chanfrar [sulcar] os para-brisas da cabines dos pilotos, danificar a fuselage e coberturas de luzes, e cobrir um avião tanto que ele fica com a cauda pesada. Em pistas com cinzas cria um problema extra quando decolagens e pousos soprarão ela no ar novamente - onde os motores pode sugá-la e ela causará dano maior para as partes móveis [dos motores].

Severity Index for Ash Encounters (from ICAO 2001, Appendix I, P. I-6):


•Class 0 Encounter: Acrid odor (e.g. sulfur gas) noted in cabin; electrostatic discharge (St. Elmo's fire) on windshield, nose, engine cowls; no notable damage to exterior or interior.


•Class 1 Encounter: Light dust in cabin (no oxygen used); exhaust gas temperature (EGT) fluctuations with return to normal values.


•Class 2 Encounter: Heavy cabin dust ("dark as night" in cabin); contamination of air handling and air conditioning systems requiring use of oxygen; some abrasion damage to exterior surface of aircraft, engine inlet, and compressor fan blades; frosting or breaking of windows due to impact of ash; minor plugging of pitot-static system (insufficient to affect instrument readings); deposition of ash in engine.


•Class 3 Encounter: Vibration of engines owing to mismatch, surging; plugging of pitot-static system to give erroneous instrument readings; contamination of engine oil hydraulic system fluids; damage to electrical system; engine damage


•Class 4 Encounter: Temporary engine failure requiring in-flight restart of engine.


•Class 5 Encounter: Engine failure or other damage leading to crash.
 

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