MICRO ConOps Model of Icing Conditions for Real-time Operations An integrated diagnosis and forecast system for in-flight and ground icing conditions Chronology and Major Issues Icing Weather Tools Workshop (Boulder, CO) 15 November 2013

Agenda  Executive Summary  Chronology of ConOps Development  Proposed Critical Icing Issues 2

Executive Summary  MICRO: Improved Flight Safety Tool ─ Engineering (ensemble of model input) ─ Scientific (Hi-res inputs)  ISC address critical issues to improve end user outputs for decision-making  ISC decisions will improve the approach of flight planning against icing hazards 3

Chronology of ConOps Development  March 2013 –Initial strawman coordinated internally w/NCAR –Comments Resolution Matrix (CRM) developed  April 2013 –Subsequent versions/meetings + presentation for ISC conference on 30 th w/latest ConOps draft  May-August 2013 –Comments compiled from FAA ISC members –Subsequent ConOps version updates  September 2013 – Adjudication Meeting with ISC members that commented on document document – Subsequent ISC comments and update v0.17 ConOps version – Expanded icing community audience for review/comment  October 2013 – Shutdown delay ConOps feedback into November – Deliverable v0.18 made to ANG-C61 (formatted draft) 4

Executive Summary of MICRO Issues  Shaping future MICRO Products and Services 1. Should only Appendix C and O conditions be depicted? Exceedance and no icing conditions as well? 2. Should severity (specific) or “standard” accretion rate be included for pilot avoidance? 3. Terminology to define or describe icing conditions a)Define severity as light, moderate, heavy or Appendix C, O, exceedance b)Language if maintaining mixed-icing conditions that includes super-cooled liquid water and ice crystals 4. How should icing products be displayed or available in gridded formats? 5. When is work expected to commence on Decision Support Tools (DSTs) to estimate aircraft-specific severity using MICRO-produced weather parameters? 5

Proposed Critical ISC Issues (1)  Use Severity or Ice Accretion Rates for conditions  Problem: No consensus among ISC, AFS or Certification  Problem: What’s the point of this if using Appendix C & O  A rate-based icing index  Problem: If indices are recognized as useful in preparation of final product then does this obviate the need for DSTs?  Terminology  Problem: language for type of icing condition varies … needed to improve NAS efficiency and safety 6

Proposed Critical ISC Issues (2)  Standard Accretion Rate on Standard airfoil  Problem: The reliability computing accretion rates even with just instituting the Standard Accretion Rate, to then properly validate it and then there's the regulatory issues and impacts.  Aircraft-specific severity estimates for Icing  Problem: the ice accreted in Appendix O conditions (previously referred to as “SLD” conditions) has effects on drag and performance that are not well-characterized by rate of accretion and this must be accommodated in the MICRO output 7

Proposed Critical ISC Issues (3)  Mixed-Phase Icing (classify as Appendix D) - developing an aircraft-specific accretion product referring to rime, glaze, and mixed  Problem: ISC on record as not supporting this and data will be there to support ice accretion but not what specific icing is actually present.  Mix-Icing needed in addition to Appendix C and O  Problem: Identification of ice crystal or mixed phase conditions is not believed to be an important issue as far as structural icing is concerned. It is important for engines and air data probes when the total water content is high. 8

Proposed Critical ISC Issues (4)  Scale of Probabilities (i.e.; Appendix C)  Problem: What is scientifically can be accomplished on continuous scale and within 10% accuracy. Is that kind of accuracy possible?  Probabilistic curve forecast approach (forecast and expand gridded forecast to include a probability curve for each accumulation category – e.g., subjective icing intensity terms, ice accretion rates aircraft performance)  Problem: Is within 10% accuracy good enough? If so, need to ensure forecast approach aligned to earlier probabilistic study is correct segway 9

Proposed Critical ISC Issues (5)  Defining Appendix Thresholds  Problem: How to manage droplet threshold is still uncertain given the current equipage measuring capability limitations to distinguish between than 40 for FZDZ. From IPHWG was certifying to one of the distributions envisioned as an option? Only small percentage of new aircraft certified for MVD >40 and partial Appendix O.  Loophole Scenario of MVD >50 but Dmax 50 but Dmax <100  Problem: Does fall into either Appendix C or O categories  Problem: Complex model outputs to determine what falls out of Appendix C or O. Maybe winter stratus conditions. NWS has no icing criteria for CBs because of convective SIGMETS – do they need one? 10

Proposed Critical ISC Issues (6)  DST converting atmospheric conditions  Problem: Converting conditions into ice accretion rate based on airframe type and airspeed using intensity vice severity icing conditions for determining both icing conditions intensity and aircraft performance  Problem: Whether to use severity/accretion forecast (DST) vice Appendices C & O  Upgrade all ASOS stations (similar to EPI) to detect FZDZ/FZRA when snow reported (mix-precip)  Problem: GA and partial Appendix O certified aircraft (business Lear Jets) most seriously effected by these mix- precipitation scenarios 11

Summary  ISC decisions down-the-road will lay out the direction of ConOps language and aviation operational approach ─ Need to start addressing issues now to establish scientific and engineering positions for approval or rejection at the Annual ISC Conference in the spring