Icing: Ad Astra Per Aspera Marcia K. Politovich Deputy Director for Science NCAR Aviation Applications Program For ATC Workshop, Washington, DC 18 November 2014 NATIONAL CENTER FOR ATMOSPHERIC RESEARCH
Translation #1: From the Mud to the Stars Translation #2: From the Ground Up
Ground Icing Precipitation (freezing rain/drizzle, snow, ice pellets) falls Effect 1. Adheres to wing (decreases lift) 2. Snow, freezing drizzle sticks to jet engine fan blades during taxi (blades bent, engine damage) Mitigation 1. De-ice before flight 2. Don t taxi in these conditions/feather engines
Ground Icing Precipitation (freezing rain/drizzle, snow, ice pellets) falls Effect 1. Adheres to wing (decreases lift) 2. Snow, freezing drizzle sticks to jet engine fan blades during taxi (blades bent, engine damage) Regulations 1. Clean wing edict 2. Company rules regarding taxiing for certain types of aircraft
Ground Icing Precipitation (freezing rain/drizzle, snow, ice pellets) falls Effect 1. Adheres to wing (decreases lift) 2. Snow, freezing drizzle sticks to jet engine fan blades during taxi (blades bent, engine damage) Effect on traffic Both: slows departure rate
Ground Icing Precipitation (freezing rain/drizzle, snow, ice pellets) falls Effect on traffic Both: slows departure rate Information needed Precipitation type, rate, liquid water equivalent amount, when condition will end
Ground Icing Products available WSDDM/LWE system Available through commercial vendor, display goes to airport operators, only available at some airports 0-2 h coverage Checktime system Quick look at holdover time NWS forecasts area and TAFs Openly available but may not have detail 0-12+ h coverage, variable granularity
Ground Icing Products under development TAIWIN Terminal Area Icing Weather Information for NextGen FAA R&D just underway Addresses ground/aloft icing conditions in terminal area focus on Appendix O NextGen Surface Observational Capability (NSOC) program will address winter precipitation type
Weather Support for Deicing Decision Making: WSDDM Past 2-h weather 30-min precip intensity forecast
Liquid Water Equivalent (LWE)
InFlight Icing Supercooled liquid water in clouds and precipitation it ti Effect Adheres to aircraft, causing loss in performance Regulations Appendix C: non-certified aircraft restricted from flying in known or forecast icingi Appendix O: for freezing drizzle/rain conditions in/out of cloud
InFlight Icing Supercooled liquid water in clouds and precipitation it ti Effect Adheres to aircraft, causing loss in performance Effect on traffic Many pilots will make a decision not to fly based on a forecast: they don t even enter the airspace Restricts airspace to certified aircraft SIGMETS, although rare, restrict airspace to all aircraft
InFlight Icing Supercooled liquid water in clouds and precipitation it ti Effect Adheres to aircraft, causing performance loss Mitigation Don t fly there if your aircraft is not certified If you are, use de/anti-icing equipment
InFlight Icing Supercooled liquid water in clouds and precipitation it ti Effect Adheres to aircraft, causing performance loss Information needed Accurate icing detection and forecast where, how much, when it will end
In-between: InFlight Icing Products many! AIRMETS (including G-AIRMETS) produced d by AWC, 0-4 h polygons for moderate or greater SIGMETS for severe icing CIP/FIP running at NWS provide 13 km/500 ft 0-18 h resolution over the CONUS MRMS Multi-Radar Multi-Sensor 3D NEXRAD mosaic GFIP/GFIS running at NCEP covers the globe Many vendor icing products International icing products ADWICE and SIGMA TAIWIN under development MICRO (higher resolution) under development elopment
CIP and FIP: Current and Forecast Icing Products Icing Probability Icing Severity SLD Potential
IPA: Icing Product Alaska Icing Probability Icing Severity SLD Potential
Global Icing Forecast Product (GFIP)
MRMS Aviation Hazard Product
Terminal Area Product - Ideas KCLE red/green waypoint tower display prototype
Engine Icing High concentrations of small ice crystals exist itat cold ldtemperatures t (usually related ltd to deep convection in moist regions) Effect 1. Ice crystals enter engine, refreeze: results in uncommanded d power loss 2. May also affect pitot tubes used to measure airspeed Regulations Advisory circular pending requiring i additional separation from thunderstorms
Engine Icing High concentrations of small ice crystals exist itat cold ldtemperatures t (usually related ltd to deep convection in moist regions) Effect 1. Ice crystals enter engine, refreeze, result in uncommanded d power loss 2. May also affect pitot tubes used to measure airspeed Effect on traffic Aircraft request deviation around tstormst
Effect on traffic Engine Icing Aircraft request deviation around tstorms Mitigation Advance warning of conditions to enable strategic rather than tactical deviations Information needed Present and forecast location and altitude, duration
Engine Icing Products under development ALPHA Algorithm to Predict HIWC Areas Preliminary CONUS version available to friendly users Other global areas under development Several commercial products Availability and location vary
Global Distribution of Engine Icing Events Based on 67 engine icing events analyzed by Boeing; map adapted from Mason (2007)
HIWC in Deep Convective Clouds: Conceptual Model Engine icing events have occurred in the trailing anvil where radar echoes are low or non-existent
Darwin ALPHA
CONUS ALPHA
Summary Icing can and does affect air traffic Ground - delays Inflight - restrictions Engine - deviations There are products out there that can enable a common picture of icing Commonality: 3D grids Could be ingested into ATM systems
Questions? This research is in response to requirements and funding by the Federal Aviation Administration (FAA). The views expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.