Communicating ground deicing weather and holdover time information to the cockpit

The National Center for Atmospheric Research (NCAR) has developed a new FAA-funded system to provide pilots real-time weather information for use in determining aircraft de/anti-icing fluid holdover times. When an aircraft experiences winter precipitation conditions on the ground, they are required to undergo a de/anti-icing procedure involving glycol-based fluids before takeoff. In order to determine the fluid holdover time, the pilot needs to know the time de-icing began, the precipitation intensity and the ambient air temperature. This information is then used with a look up chart to determine how long they can expect their fluid to provide protection under the given conditions. To simplify this process, an automated holdover time determination system was developed known as the Checktime algorithm. This algorithm is currently being tested at the Denver, Chicago O'hare and Cleveland Hopkins airports. This paper describes the methods used to get the information to the pilots and ground crews, the advantages and drawbacks to those methods, as well as the feedback received from the pilots and ground crews on how to improve the product.