NASA to study aircraft engine icing puzzle

NASA says it has begun a study of why airplanes flying in or near tropical regions in the summer can have an engine fill up with ice, freeze and then shut down.The phenomenon, known as engine core ice accretion, has been documented more than 150 times since 1988, prompting NASA aviation safety experts to prepare a flight test program in northern Australia to learn more about the occasional hazard and try to determine what can be done to prevent it, a NASA release said."It's not happening in one particular type of engine and it's not happening on one particular type of airframe," Tom Ratvasky, a NASA flight research engineer said. "The problem can be found on aircraft as big as large commercial airliners, all the way down to business-sized jet aircraft."No accidents have been attributed to the phenomenon but there have been some close calls.In 2005, both engines of a Beechcraft business jet failed at 38,000 feet above Jacksonville, Fla., forcing the pilot to glide the aircraft to an airport, dodging thunderstorms on the way down. Engine core ice accretion was blamed.Scientists say they suspect the trouble occurs around tropical storms that move moist air from low altitudes to high altitudes where temperatures are very cold, creating high concentrations of ice crystals."We need to understand what that environment is out there and, even though it may be a rare case, be able to fly through those icing conditions unscathed," Ratvasky said. "Or if we can find ways of detecting this condition and keep aircraft out of it, that's something we're interested in doing."