1. Saab 2000 (AEW&C) Certification for flight in icing conditions Wim Willemse October 19, 2010

2. PAGE 2 2010-10-19 Saab 2000 (AEW&C) Certification for flight in icing conditions Introduction Platform Description – external changes Effect of ice accretion on external changes Definition of the artificial ice shapes Flight test Acknowledgments

3. PAGE 3 2010-10-19 Saab 2000 (AEW&C) Certification for flight in icing conditions INTRODUCTION Airborne Early Warning and Control Latest generation of the ERIEYE radar and Mission System Self Protection System Identification Friend or Foe The Saab 2000 (AEW&C) should full-fill the same civil certification requirements as the Saab 2000 airliner: To operate into known icing conditions, the aircraft must be certified in accordance with the criteria of FAR/JAR Part 25, Appendix C.

4. PAGE 4 2010-10-19 Saab 2000 (AEW&C) PLATFORM DESCRIPTION DOU MAW/LWS Towed decoy WT pods Chaff/Flare

5. PAGE 5 2010-10-19 EFFECT OF ICE ACCRETION Wing Tip Pods – Unprotected Effect of Ice accretion - Increased drag - Possible effect on aileron aerodynamics Has been investigated by flight test with artificial ice shape. Towed decoy – Unprotected Effect of Ice accretion - Increased drag Has been investigated by flight test with artificial ice shape.

6. PAGE 6 2010-10-19 EFFECT OF ICE ACCRETION DOU Struts – Protected Clean struts decrease directional stability and increase the drag. (Verified by CFD analysis and Wind tunnel tests) Effect of Ice accretion - Increased drag – Requires protection - Decreased strut lift (side force) – Less negative effect on directional stability

7. PAGE 7 2010-10-19 EFFECT OF ICE ACCRETION Vertical tail extension (30 inches) - Unprotected Effect of the 3 inch double horn ice tested in the wind tunnel. - Increased drag - Slightly increased directional stability - Slightly increased rudder efficiency Investigated by flight test with artificial ice shape.

8. PAGE 8 2010-10-19 EFFECT OF ICE ACCRETION MAW/LWS sensors – Unprotected No significant effect of ice accretion on pitot-tubes and angle of attack vanes

9. PAGE 9 2010-10-19 DEFINITION OF ARTIFICIAL ICE SHAPES ONERA Ice code Code produced by Onera Icing code used for Saab 2000 artificial ice shapes Accepted by FAA and EASA 2-dimensional code

10. PAGE 10 2010-10-19 DEFINITION OF ARTIFICIAL ICE SHAPES Icing conditions Requirement FAR/JAR: Appendix C For unprotected parts: 45 minutes holding in Continuous Maximum pinnacle length up to 3 inch Droplet size: 20 μm LWC as function of temperature – according to Appendix C.

11. PAGE 11 2010-10-19 DEFINITION OF ARTIFICIAL ICE SHAPES Artificial ice shape on wing tip pod The ice shape is defined by two shapes: one top view and one side view. The thick red line is the selected shape for flight test. The ice shapes are made dimensionless with the “chord length”: 2.14m Roughness has been added up to 10 % length of the wing tip pod: (a) roughness height: 3 mm (b) particle density: 8 to 10/cm2

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15. PAGE 15 2010-10-19 Artificial ice shape on towed decoy The ice shape is defined by two shapes: one top view and one side view. The thick line (-6 C) is the selected shape for flight test. The ice shapes are made dimensionless with the “chord length”: 1.454m Roughness has been added up to 10 % length of the wing tip pod: (a) roughness height: 3 mm (b) particle density: 8 to 10/cm2 DEFINITION OF ARTIFICIAL ICE SHAPES

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19. PAGE 19 2010-10-19 DEFINITION OF ARTIFICIAL ICE SHAPES Artificial ice shape on vertical tail extension

20. PAGE 20 2010-10-19 Saab 2000 (AEW&C) FLIGHT TEST Flight in natural icing boots on DOU struts Dry-air flight test with artificial ice shapes Effect on flying qualities Aircraft performance #1B-AEW Approach ice. 0.5” on protected, 3” unprotected #5-AEW Left Upper Wing failure case. 1.5” on failed surface.

21. PAGE 21 2010-10-19 Saab 2000 (AEW&C) Dry-air flight tests Flying Qualities tests Test\Ice1B5 Stall CharacteristicsXX Push Over to 0 gX Directional ControlX Lateral ControlX Steady Heading SideslipXX Dutch RollX Vibration and BuffetingX LandingsXX Selected Flying Qualities tests, artificial ice configuration and flight conditions are ”worst case” from the Saab 2000 certification.

22. PAGE 22 2010-10-19 Acknowledgments Nenad Jankovic – Manager applied aerodynamics Per Weinerfelt – Specialist Mathematical and numerical modeling Henrik Åslund – Senior Research Engineer Aerodynamics Karl-Erik Eklund – Advanced Design Engineer Ronny Gyllensten – Advanced Design Engineer