Presented at: NCAR By: Paul Pellicano Date: November, 2013 Federal Aviation Administration MICRO ConOps

2 Federal Aviation Administration MICRO ConOps November, 2013 DST Aircraft index based on certification basis –Certified for icing Transport category airplanes over 60,000 lb. wing anti-ice, wing leading edge devices, no negative service history Other transport Small and commuter, Amendment or higher Small and commuter, Amendment or higher with no negative service history Earlier than or with icing events –Light icing, limited time in moderate icing –Not certified for icing

3 Federal Aviation Administration MICRO ConOps November, 2013 Agenda Ice accretion rate MVD PIREPS GA

4 Federal Aviation Administration MICRO ConOps November, 2013 Ice accretion rate

5 Federal Aviation Administration MICRO ConOps November, 2013 Ice accretion rate 5

6 Federal Aviation Administration MICRO ConOps November, 2013 DST FAA cannot require airplane specific data from manufacturers –No plan to require it for new airplanes Could ask –FAA not likely to get positive response –Data doesn’t exist for older airplanes

7 Federal Aviation Administration MICRO ConOps November, 2013 MVD Accretion rate MVD 40 Appendix O Certification

8 Federal Aviation Administration MICRO ConOps November, 2013 PIREPS What will be “known” SLD? 8

9 Federal Aviation Administration MICRO ConOps November, 2013 PIREPS AOPA ASF Socata Accident 9

10 Federal Aviation Administration MICRO ConOps November, 2013 PIREPS 10

11 Federal Aviation Administration MICRO ConOps November, 2013 In-Flight - Indirect Surface observations are needed at smaller airports to also increase safety of transport category airplanes EventPhaseAltitude, ftAirportDistance, nm American Eagle 4184Hold10,000ORD60 Comair 3272Descent7,000DTW19 Comair 5054Cruise17,000PBI47 Continental Express 2733Climb11,500 – 17,400 LIT37 MEM125 American Eagle 3008Climb7,000 – 11,700 SPB25 LAX130

12 Federal Aviation Administration MICRO ConOps November, 2013 In-Flight - Indirect Surface observations are needed at smaller airports to also increase safety of all airplanes

13 Federal Aviation Administration MICRO ConOps November, 2013 General Aviation Comment 82 - Part 25 is NOT GA! GA has the most to gain but is it properly addressed? Disposition - Paul stated Part 23 certification is the same as Part 25. It appears for now GA is address adequately in ConOps –For new part 23 airplanes – assume AFM language will be similar 13

14 Federal Aviation Administration MICRO ConOps November, 2013 General Aviation Existing fleet –Much bigger than projected new airplanes Most “detect and exit” Market impact First may be business jets –No explicit prohibition in SLD –Must exit severe icing Cockpit display –Include SLD and PIREPS –Training/AIM Ice accretion location versus accretion rate 14

15 Federal Aviation Administration MICRO ConOps November, 2013 General Aviation SIGMETs –Two levels, one that would only impact airplanes with SLD or severe icing AFM language? Smaller airports Unmanned Aerial Systems –Certification standards will require system or ground operator to know if aircraft in Appendix C and/or Appendix O –Must be able to report FZDZ and FZRA 15

16 Federal Aviation Administration MICRO ConOps November, 2013 General Aviation Part 23 rulemaking –Congressional mandate –NPRM 2015 Rules high level and not prescriptive –“Must be able to safely operate in the icing conditions for which certification is requested” ASTM Standards –Will define the icing conditions –AFM language expected to be similar to part 25 16

17 Federal Aviation Administration MICRO ConOps November, 2013 Back-up Slides 17

18 Federal Aviation Administration MICRO ConOps November, 2013 Current ASOS Deficiencies ASOS does not report FZDZ –Belief that LEWDI cannot detect drizzle size drops –Drizzle precipitation rates below ASOS specification ASOS does not report FZRA when snow is being reported –Wet snow can adhere to ice detector FZRA Reporting May Be Inaccurate for short periods of time –Ice detector has to be heated to deice ASOS does not detect PL

19 Federal Aviation Administration MICRO ConOps November, 2013 Current ASOS Deficiencies Sources –Current Capabilities for Icing Nowcasting and Forecasting in the Terminal Area, Marcia K. Politovich and Scott Landolt, Terminal Area Icing Weather Information System, Product Development Team, National Center for Atmospheric Research A Multisensor Approach to Detecting Drizzle on ASOS, Charles G. Wade, National Center for Atmospheric Research, Boulder, Colorado Published in Journal of Atmospheric and Ocean Technology, Volume 20, 2003

20 Federal Aviation Administration MICRO ConOps November, 2013 Why we need ASOS Ground Operations In-Flight Efficiency Safety Cost

21 Federal Aviation Administration MICRO ConOps November, 2013 Ground Operations Outside Air Temperature Approximate Holdover Times Under Various Weather Conditions (hours: minutes) Degrees Celsius Degrees Fahrenheit Type III Fluid Concentration Neat Fluid/Water (Volume %/V o lume %) Freezing Fog Snow, Snow Grains or Snow Pellets Freezing Drizzle* Light Freezing Rain Rain on Cold Soaked Wing** Other‡ VeryLight † Light † Moderate -3 and above 27 and above 100/00:20 - 0:400:35 - 0:400:20 - 0:35 0:10 - 0:20 0:08 - 0:10 0:06 - 0:20 75/250:15 - 0:300:25 - 0:350:15 - 0:25 0:08 - 0:15 0:06 - 0:10 0:02 - 0:10 50/500:10 - 0:200:15 - 0:200:08 - 0:15 0:04 - 0:08 0:05 - 0:09 0:04 - 0:06 below -3 to -10 below 27 to /00:20 - 0:400:30 - 0:350:15 - 0:30 0:09 - 0:15 0:10 - 0:20 0:08 - 0:10 CAUTION: No holdover time guidelines exist ***75/250:15 - 0:300:25 - 0:300:10 - 0:25 0:07 - 0:10 0:09 - 0:12 0:06 - 0:09 below -10 below /00:20 - 0:400:30 - 0:350:15 - 0:30 0:08 - 0:15 SAE Type III fluid may be used below -10  C (14  F), provided the freezing point of the fluid is at least 7  C (13  F) below OAT and aerodynamic acceptance criteria (LOUT) are met. For the currently available Type III product, the High Speed LOUT is -29 °C (-20.2 °F) and the Low Speed LOUT is °C (2.3 °F). Consider the use of SAE Type I when Type III fluid cannot be used.

22 Federal Aviation Administration MICRO ConOps November, 2013 Ground Operations * Use light freezing rain holdover times if positive identification of freezing drizzle is not possible

23 Federal Aviation Administration MICRO ConOps November, 2013 Ground Operations Aircraft are currently not certificated for operations in freezing precipitation. However, they are not prohibited from take-off in freezing precipitation provided: –the PIC follows the ground guidance –there are no AFM limitations

24 Federal Aviation Administration MICRO ConOps November, 2013 Airplane Limitations Airplanes certified for flight in icing –Cloud icing conditions defined in CFR part 25, Appendix C After the 1994 Roselawn accident –Airworthiness Directives require immediate exit from severe icing in AFM Limitations section –“Freezing drizzle and freezing rain may be conducive to severe icing” New airplanes –Part 25 rulemaking –Part 23 rulemaking In interim, most new part 23 airplanes insert prohibition in AFM Limitations section

25 Federal Aviation Administration MICRO ConOps November, 2013 Proposed Part 25 Rule Airplanes certified for flight in icing must show –Safely operate in SLD; –Detect SLD and safely exit all icing; or –Safely operate in a portion of SLD, detect unapproved SLD conditions and safely exit all icing

26 Federal Aviation Administration MICRO ConOps November, 2013 In-Flight - Direct Approach and landing –A part 23 icing Aviation Rulemaking Committee (Reference 4) identified 48 events (23 fatal) on part 23 airplanes from 1979 to 2009 in which there was evidence of supercooled large drop (SLD) conditions. –The majority of these (75%) was on approach and landing, and in 20% of these events snow was present. –The prevalence of “wet snow” is indicated by the fact the mean the average mean ambient temperature was 29.2°F, and the median was 32.0°F

27 Federal Aviation Administration MICRO ConOps November, 2013 In-Flight - Direct Fatal accident of an air ambulance on approach to Rawlins, WY, in 2005 Light snow and mist were the only precipitation reported, temperature of 32°F. Witnesses in the vicinity of RWL reported surface weather conditions varying from freezing rain to heavy snow

28 Federal Aviation Administration MICRO ConOps November, 2013 In-Flight - Indirect The lead scientist in the development of the NCAR Integrated Icing Diagnostic Algorithm has stated (Bernstein, 1999) that “surface observations are the most powerful forecasting tool we have for finding SLD [Supercooled Large Droplet] conditions aloft, and FZDZ observations are our best indicator of the simultaneous occurrence of FZDZ aloft.” Final Report: Freezing Drizzle Algorithm Development,” September 21, 1999, Prepared for the National Weather Service by Raytheon Information Technology and Scientific Services (RITSS)

29 Federal Aviation Administration MICRO ConOps November, 2013 In-Flight - Indirect Surface observations of freezing drizzle (FZDZ) were an excellent indicator of FZDZ aloft when near the observation (70% occurrence within 25 km) and at altitudes up to 5,000 ft., NASA CR-2001/ “Evaluation of NCAR Icing/SLD Forecasts, Tools, and Techniques Used During the 1998 NASA SLD Flight Season,” August 2001, Ben Bernstein, National Center for Atmospheric Research

30 Federal Aviation Administration MICRO ConOps November, 2013 Cost On Oct. 31, 2002, twelve United Airlines 737 aircraft incurred jet engine damage after experiencing a winter storm at Denver, Colorado. –The damage was primarily bent fan blade tips, and was consistent with ice being ingested into the engines. –Total damage was reported by United Airlines as being over $2 million dollars, with one engine requiring replacement. –The damage was noted after the aircraft landed at their destination airports. The METAR and weather observer at Denver reported mist and light snow –Ground personnel reported the presence of freezing drizzle.