Remote Sensing of Inflight Icing Conditions Dr. Charles C. Ryerson Cold Regions Research and Engineering Laboratory Engineering Research and Development Center U.S. Army Corps of Engineers

2 Inform of emerging capability for remote detection and dissemination of tactical inflight structural icing information Seek proponency for more rapid development and fielding Purpose

3 Inflight Icing Problems Technological Solutions Development Program Conclusions Content applicable to all five User Forum presentation areas Outline

4 Icing forecasts (strategic) can unnecessarily restrict and cancel flights (tactical) Low, slow aircraft <20,000', laminar flow air- foils, & rotorcraft have most icing problems Control anomalies Tail plane stalls Simulated Kosovo winter warfight for DARPA: ~ 58% flights affected ~ 24% flights canceled Hunter UAV only flown April-October in Kosovo due to icing - Inside the Army - 21 Feb 2000 Problems

5 Inflight Icing Accidents RQ-1 Predator accident report released Released: 23 Dec LANGLEY AIR FORCE BASE, Va. (AFPN) -- Officials investigating the April 18 crash of an RQ-1 Predator unmanned aerial vehicle near Tuzla Air Base, Bosnia, have determined the accident resulted from a combination of mechanical and human factors. The Predator, which belonged to the 11th Reconnaissance Squadron at Nellis Air Force Base, Nev., was returning from a reconnaissance mission over Kosovo in support of Operation Allied Force. It was destroyed upon impact. According to the accident investigation board report, the Predator experienced a fuel problem during its descent into Tuzla. Upon entering instrument meteorological conditions and experiencing aircraft icing, the Predator lost engine power.

6 Remotely sense icing conditions Remotely sense icing conditions ahead of aircraft ahead of aircraft Disseminate icing information for Disseminate icing information for use as a tactical decision aid to use as a tactical decision aid to improve safety improve safety Allow aircraft to avoid and exit Allow aircraft to avoid and exit Ground-based and airborne systems Ground-based and airborne systems Technological Solutions

7 Ground-Based Sensing

8 Airborne Sensing

9 Multi-Band Radar Drizzle detection with polarization XKaKa W

10 Multi-Band Radiometer 22 and 60 GHz

11 Differential brightness temperatures at 37 and 89 GHz 2 degrees Cloud Flight Level Temperature Drizzle Cool Brightness from cloud, upper atmosphere Polarized Radiance if Drizzle present Cold Brightness from Space, Upper Atmosphere Hot Brightness from surface, lower atmosphere Warm Brightness from cloud, lower atmosphere 35 m/km Airborne Microwave Radiometer Polarization to detect ice vs liquid water Neural network retrievals Emphasize quiet frequencies

12 Partners: DoD, NASA, FAA, NOAA, NCAR, industry, universities, MSC coordination Programs: NASA: 5-yr ground-based plan, 10-yr airborne plan, FY01 ground-based radiometer evaluation FAA/NCAR: 7-yr plan, FAA Inflight Aircraft Icing Plan, ground-based radar build CRREL: coordinate with NASA/FAA, DoD emphasis, Concept Evaluation Program Approach: Operational, Meteorological, Technological Development Program

ALLIANCE ICING RESEARCH STUDY “Worst Weather in the World” 6288’

14 Documented Progress

15 Conclusions Prototypes: Ground - next few yrs Airborne yrs depending upon funding Technical Issues: cost, size, power, weight, range, resolution, accuracy, temperature, down-select of best technologies Operational issues: Cockpit Integration (AWIN), weather system infrastructure, hazard characterization Possible DARPA program: icing, thunderstorms, turbulence, visibility, wires