An international field research campaign led by Airbus and NASA has gathered a wealth of data on icing conditions in convective weather, especially on ice crystals that cause engine icing. The eight-week effort ended in March in Darwin, Australia, and the researchers expect to publish their report early next year. The partners in the project hope to gain a better understanding of icing conditions that will allow them to devise mathematical models for equipment manufacturers to use when designing detection systems.
Scientists in the propulsion system laboratory (PSL) at NASA’s Glenn research center in Cleveland, Ohio, have developed a test facility that can recreate high-altitude engine icing, a long-awaited capability that should equip the aviation industry to tackle a poorly understood hazard.
Over the last 20 years, the aviation industry has documented more than 200 incidents in which turbofans have lost power during high-altitude flights, according to NASA.
France’s Zodiac Aerospace has unveiled a new in-flight ice detection system capable of detecting ice in any format, including large droplets. Zodiac says current systems are incapable of detecting ice crystals. The new ice-detection system is set to begin flight-testing in 2016, with service entry planned for 2017.
Researchers are gradually coming to understand the physics of in-flight engine icing due to ice crystals. In response to this enhanced knowledge of the subject, civil aviation authorities, such as the European Aviation Safety Agency (EASA) and the U.S. Federal Aviation Administration (FAA), are considering more stringent certification requirements.
Current in-flight icing detection systems (FIDS) cannot detect ice crystals. But equipment manufacturer Zodiac Aerospace (Booth E07) is developing a new FIDS, using optical techniques. It will detect any form of icing and will be able to tell which form of ice–small or large supercooled droplets, crystal and so forth–is impacting the aircraft. It will give the crew specific warnings when large-droplet icing conditions or ice crystals are encountered, François Larue, head of research and technology of Zodiac’s Aircraft Systems division, told AIN.
The FAA is reissuing and revising a Special Airworthiness Information Bulletin (SW-08-03R4) covering recommendations for rotorcraft powered by turboshaft engines flying into snowy or icy conditions. The SAIB describes procedures to reduce the probability of an uncommanded in-flight engine shutdown due to snow and/or ice ingestion and reminds operators that most helicopters are not approved/equipped for flight into icing conditions.
Even as researchers study ways to improve detection of in-flight icing and make airframes and engines more resistant to icing conditions, they continue to struggle to understand the icing phenomenon–especially the formation of ice crystals–according to speakers at a conference on the subject organized by the European Aviation Safety Agency (EASA) in Cologne, Germany recently. Ice-prevention techniques present their own challenges, which aircraft makers, airports and ground handlers are endeavoring to solve.
Boeing has advised GEnx engine operators that it is revising the 787’s and the 747-8’s flight manuals to prohibit flight within 50 nm of thunderstorms that may contain ice crystals. Following Boeing’s recommendation, Japan Airlines immediately announced it would switch aircraft on two routes. From April to November, GEnx-powered aircraft suffered six engine-icing events, according to a GE statement. All aircraft landed at their planned destinations, said the engine maker, and none of the incidents involved in-flight shutdowns–only temporary thrust losses.
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