Comparative analysis of optical in-situ probes and the MSG satellite for improved detection of aircraft icing conditions

In-flight icing poses a significant threat to aircraft safety, potentially leading to the distortion of airflow over wings, loss of lift force, reduced speed, and even stall. While current aircraft are equipped with protection systems against icing, supercooled large droplets (SLDs) still present a safety hazard as they can impinge behind the protected surfaces of an aircraft. To detect and understand the characteristics of SLD conditions, airborne in-situ measurements provide a comprehensive examination of cloud microphysical properties using sensors mounted on an aircraft. One well-established instrument for measuring cloud particles is the Cloud Imaging Probe (CIP), which has been widely used for cloud measurements. However, it is associated with measurement uncertainties. A newer 2D imaging probe, the High-Speed Imager (HSI), is designed to address some of the limitations of the CIP. The CIP and HSI probes were integrated into SAFIRE's research aircraft ATR-42 during the SENS4ICE flight campaign conducted in Southern France in April 2023. These in-situ measurements served as reference data for the validation of new ice detection sensors. The primary objective of this study is to develop a methodology aimed at evaluating CIP measurements, particularly in finding out SLDs and large droplet icing conditions following the criteria outlined in Appendix O of aircraft certification standards. The processed data and images from a selected icing encounter are then compared with the HSI data to discriminate their measurement characteristics. The findings can provide support for future flight campaigns to choose the suitable instrument. The presented data evaluation procedure is then demonstrated on an observational flight of the SENS4ICE campaign. An incoming warm front system with a high likelihood of containing SLD is sampled throughout the flight. Cloud measurements were conducted at temperatures ranging from 0 to -15 degrees Celsius and altitudes below 5 km. The proposed methodology effectively detected large droplet icing conditions, which extended for nearly an hour. Additionally, the in-situ cloud data collected was used to characterize atmospheric conditions conducive to SLD formation. The results were subsequently cross-validated with Meteosat Second Generation (MSG) satellite products to enable a comprehensive analysis. The tool utilized predominantly categorized the cloud-top of the sampled clouds as mixed-phase. However, the confidence level in these classifications is relatively low due to the obstruction caused by higher-level clouds, limiting the satellite’s observation of the cloud system

A flux controlled electronically tunable fully floating OTA based memristor emulator

In this paper, flux controlled high frequency floating/grounded type memristor emulator circuit based on single OTA (Operational Transconductance Amplifier) is introduced by using CMOS technology. The emulator is realized using single OTA, multi output transconductance amplifier, a grounded resistor and a grounded capacitor. The proposed circuit can be configured in both incremental and decremental topology by changing the connections. The proposed circuit has been simulated in LT-Spice using 0.18 μm CMOS parameters at a supply voltage of ± 1.5 V. The memristor characteristics can be electronically tuned by changing the transconductance of the OTAs. In addition, with change of the capacitor value in the proposed circuit, the pinched hysteresis loop observed in the current versus voltage plane can be held at higher frequencies. The proposed emulator circuit performs well up to 20 MHz. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

Overview of Cloud Microphysical Measurements during the SENS4ICE Airborne Test Campaigns: Contrasting Icing Frequencies from Climatological Data to First Results from Airborne Observations

The European Union’s Horizon 2020 programme has funded the SENS4ICE (Sensors for Certifiable Hybrid Architectures for Safer Aviation in Icing Environment) project [1], an innovative approach for the development and testing of new sensors for the detection of supercooled large droplets (SLD). SLD may impinge behind the protected surfaces of aircraft and therefore represents a threat to aviation safety. The newly developed sensors will be tested in combination with an indirect detection method on two aircraft, in two parallel flight programs: One on the Embraer Phenom 300 in the U.S. and one on the ATR-42 in Europe. In this framework the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center) is in charge of the airborne measurements and data evaluation of the microphysical properties of clouds encountered during the SENS4ICE field campaigns in February, March and April 2023. We present the instrumentation that is used in the flight experiments for the characterization of icing environments and for the validation and performance assessment of new sensors for the detection and discrimination of Appendix O and Appendix C conditions [2, 3]. Further, with partners from Centre Europeen De Recherche Et De Formation Avancee En Calcul Scientifique (CERFACS), the German Weather Service (DWD), the Italian Aerospace Research Center (CIRA) and Leading Edge Atmospherics (LEA), we present the considerations that were undertaken to find the best campaign location with highest frequency of icing occurrence on a climatological basis, taking into account the safety requirements of the aircraft. Four data sets of icing conditions based on various meteorological input data (model and observations) have been analyzed to provide an overview of the occurrence of icing. The data give a good impression on the geographical and vertical distribution of icing conditions above Europe and the Northern U.S. in general and specifically at higher altitudes (> 750 hPa or 8000ft) for the European campaign. We find enhanced icing frequencies between 1 to 5% at altitudes between 2 and 6 km even in the spring, summer and autumn months above Europe. We show highlights from selected individual cases from the North American test campaign performed in February and March 2023. The analysis gives a first impression of the extensive data set of icing conditions made available by the SENS4ICE project for sensor evaluation and for validation of satellite observations and model forecasts