22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-1.10.3
AIRBORNE OBSERVATION OF ICE ACCRETION AND AIRCRAFT PERFORMANCE IN ARTIFICIAL AND NATURAL SUPERCOOLED ICE CLOUDS ON DORNIER 228 AND 328 AIRCRAFT
F. Scröder (1), D. Welte (2), T. Hauf (3)
(1) Inst. für Physik der Atmosphäre, DLR, D-82234 Wessling, Germany;
(2) Dornier Luftfahrt GmbH, D-82230 Wessling, Germany;
(3) Inst. Für Meteorologie und Klimatologie, Universität Hannover, Germany
Keywords: aircraft icing, supercooled large drops, airborne observations
Results from two airborne experiments
investigating aircraft icing, aircraft
performance and cloud microphysics
associated with supercooled large drops
(SLD) are presented. Dornier-Luftfahrt
performed in-flight tests, where external
surfaces of a DO-328 turboprop aircraft
were exposed to artificially generated SLD
with 180 µm mean volume diameter (MVD).
High liquid water content (LWC) up to 0.65
g m-3 caused substantial ice accretion
behind boot-protected regions of the wings.
Visual cues associated with SLD are
described. Limitations for flights in severe
icing conditions and exiting procedures
have been derived.
DLR performed several research flights
within natural icing conditions on a Do-228
aircraft equipped with cloud microphysicaland
icing documentation instrumentation.
Specified weather-forecasts helped to find
atmospheric regions that were
characterized by at least moderate icing
conditions and temporarily by the
occurrence of SLD. Two cases with severe
icing and ice accretion rates exceeding 3
mm min-1, temporarily associated with SLD,
have been met. SLD did not dominate, but
significantly contributed to LWC during
icing incidents. Back-running ice has been
observed in the presence of SLDs. Heavy
icing was experienced in stratiform clouds
with embedded convection, average LWC
below 0.3 g m-3 and within a -10 to -7 oC
temperature interval.
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