No more in-flight icing

Airlines now have a new tool for avoiding in-flight icing, which can threaten smaller commuter planes and delay larger commercial aircraft as they land or take off.

Called CIP, for the Current Icing Potential, the online display offers high-precision maps and plots, updated hourly, to identify areas of potential aircraft icing produced by cloud droplets, freezing rain, and drizzle.

Researchers at the US National Center for Atmospheric Research (NCAR), with funding from the US Federal Aviation Administration (FAA), developed new methods and software for detecting and forecasting icing potential in the atmosphere. They then applied these methods to produce CIP, a Web-based display describing current icing conditions.

CIP goes into service this week for use by meteorologists and airline dispatchers. Its use by pilots and air traffic controllers is pending FAA approval. A companion tool, called FIP (Forecast Icing Potential), which forecasts potential icing up to 12 hours ahead, is still in development at NCAR and classified as experimental by the FAA.

Pilots can encounter winter icing anywhere in the US, at altitudes up to 18,000 feet, and sometimes higher, according to NCAR’s Marcia Politovich, head of the FAA’s In-Flight Icing Product Development Team. Most vulnerable are Alaska, the Pacific Northwest, the Great Lakes, the Northeast, the Appalachians, and the Rocky Mountains.

‘CIP helps dispatchers identify areas of potential icing so pilots can feel more confident about choosing a flight path,’ says Politovich.

The FAA approved CIP as a tool for dispatchers to make fly/no-fly decisions and for flight planning, route changes, and altitude selection. The on-line display is derived from surface observations, numerical models, satellite and radar data, and pilot reports.

The National Weather Service operates the new system from the Aviation Weather Center in Kansas City, MO. CIP will supplement but not replace the forecast or intensity information in the NWS AIRMET, the traditional weather alert issued at six-hour intervals.

CIP will most benefit commuter planes and other propeller-driven aircraft, says Politovich. Smaller aircraft are more vulnerable to icing hazards because they cruise at lower, ice-prone altitudes. They also lack mechanisms common on jets that prevent ice buildup by heating the front edges of wings. Once approved for use by air traffic controllers, CIP will also benefit jet aircraft by enabling controllers to guide incoming flights so they avoid circling at altitudes where ice could accumulate.

Cancellations and delays due to icy weather can cost airlines millions of dollars in a single day. On March 20, 2000, icing conditions at Denver International Airport forced Air Wisconsin to cancel 152 flights. United cancelled 159 outbound and 140 inbound flights the same day, most because of weather.

‘New technology is allowing better detection,’ says NCAR’s Benjamin Bernstein, who developed FIP. ‘Combined with new forecasting methods and the timeliness and accessibility of the Web, these breakthroughs could significantly reduce icing tragedies and losses.’

Commuter pilots at Air Wisconsin, Atlantic Coast, ComAir, and SkyWest tested the technology and gave researchers feedback throughout the development process. NCAR’s primary sponsor is the National Science Foundation.