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SLD and Ice Crystal Discrimination with the Optical Ice Detector
ISSN: 0148-7191, e-ISSN: 2688-3627
Published June 10, 2019 by SAE International in United States
Annotation ability available
In response to new safety regulations regarding aircraft icing, Collins Aerospace has developed and tested an Optical Ice Detector (OID) capable of discriminating among icing conditions appropriate to Appendix C and Appendix O of 14 CFR Part 25 and Appendix D of Part 33. The OID is a short-range, polarimetric lidar that samples the airstream up to ten meters beyond the skin of the aircraft. The intensity and extinction of the backscatter light correlate with bulk properties of the cloud, such as water content and phase. Backscatter scintillation (combined with the outside air temperature from another probe) signals the presence of supercooled large droplets (SLD) within the cloud-a capability incorporated into the OID to meet the requirements of Appendix O.
Recent laboratory and flight tests of the Optical Ice Detector have confirmed the efficacy of the OID to discriminate among the various icing conditions. Drizzle-sized droplets, mixed with a small droplet cloud in the Collins Cloud Chamber, appear as scintillations in the lidar signal when it is processed pulse-by-pulse. Averaging the signal over multiple pulses, causes large droplets to become obscured by the small droplet background. In addition, the OID has discriminated and quantified mixed phase in a flight test aboard the NASA DC-8 Airborne Science Laboratory. The threshold for ice water quantification is less than 0.5 g/m3 IWC, while that for liquid water cloud detection is less than 0.05 g/m3 LWC.
CitationAnderson, K. and Ray, M., "SLD and Ice Crystal Discrimination with the Optical Ice Detector," SAE Technical Paper 2019-01-1934, 2019, https://doi.org/10.4271/2019-01-1934.
- Federal Aviation Administration , “Airplane and Engine Certification Requirements in Supercooled Large Drop, Mixed Phase, and Ice Crystal Icing Conditions,” Final Rule, Docket No. FAA-2010-0636: Amendment Nos. 25-140 and 33-34; Federal Register Vol. 79, No. 213, November 4, 2014.
- Ray, M. and Anderson, K. , “Analysis of Flight Test Results of the Optical Ice Detector,” SAE Int. J. Aerosp. 8(1):1-8, 2015, doi:10.4271/2015-01-2106.
- SAE International Standards , “Minimum Operational Performance Specification for Inflight Icing Detection Systems,” AS5498A, Dec. 5, 2017.
- Ray, M., Nesnidal, M., and Socha, D. , “Optical Detection of Airborne Ice Crystals and Water Droplets,” in 1st AIAA Atmospheric and Space Environments Conference, San Antonio, TX, June 22-25, 2009, Paper AIAA 2009-3863.
- Halama, G., Ray, M., Anderson, K., and Nesnidal, M. , “Optical Ice Detection: Test Results from the NASA Glenn Icing Research Tunnel,” in 2nd AIAA Atmospheric and Space Environments Conference, Toronto, ON, Aug. 2-5, 2010, Paper AIAA 2010-7532.
- Anderson, K., Halama, G., Ray, M., and Nesnidal, M. , “Cloud Phase Discrimination Using the Optical Icing Conditions Detector: Wind Tunnel and Flight Test Results,” SAE Technical Paper 2011-38-0076, 2011, doi:10.4271/2011-38-0076.
- Yang, P., Wei, H., Huang, H., Baum, B. et al. , “Scattering and Absorption Property Database for Nonspherical Ice Particles in the Near- Through Far-Infrared Spectral Region,” Applied Optics 44(26):5512-5523, 2005.
- Ray, M., Anderson, K., and Miller, M. , “Large Droplet Detection by Statistical Fluctuations in Lidar Backscatter,” U.S. Patent 9,658,337.
- Gimmestad, G. , “Re-Examination of Depolarization in Lidar Measurements,” Applied Optics 47(21):3795-3802, 2008.
- Ratvasky, T., Strapp, W., Lillie, L., Proctor, F. et al. , “Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns,” 2019 SAE International Conference on Icing of Aircraft, Engines, and Structures, SAE 2019-01-2027, 2019.
- Davison, C. R., MacLeod, J. D., Strapp, J. W., and Buttsworth, D. R. , ‘Isokinetic Total Water Content Probe in a Naturally Aspirating Configuration: Initial Aerodynamic Design and Testing”, in 46th AIAA Aerospace Sciences Meeting and Exhibit, Jan. 10, 2008, Reno, NV, AIAA-2008-0435.
- Davison, C.R., Landreville, C., and MacLeod, J.D. , “Initial Development and Testing of Isokinetic Probe to Measure Total Water Content During Ground and Airborne Testing,” NRC, LTR-GTL-2010-0002, Ottawa, Mar. 2010.
- Strapp, J.W., Lilie, L., Ratvasky, T., Davison, C. et al , “Isokinetic TWC Evaporator Probe: Development of the IKP2 and Performance Testing for the HAIC-HIWC Darwin 2014 and Cayenne Field Campaigns,” in 8th AIAA Atmospheric and Space Environments Conference, AIAA Aviation, AIAA 2016-4059, 2016, doi:10.2514/6.2016-4059.
- Davison, C.R., Strapp, J.W., Lilie, L., Ratvasky, T.P. et al. , “ Isokinetic TWC Evaporator Probe: Calculations and Systemic Error Analysis,” in 8th AIAA Atmospheric and Space Environments Conference, June 17, 2016, Washington, DC, AIAA-4060, doi:10.2514/6.2016-4060.