An experimental cockpit display for TDWR wind shear alerts
This paper describes an experimental system for cockpit display of Terminal Doppler Weather Radar (TDWR) wind shear warnings. The TDWR is a ground-based system for detecting wind shear hazards that pose a threat to aviation, During the Summer of 1990, wind shear warnings generated by the Lincoln-operated TDWR testbed radar at Orlando, Florida were transmitted in real-time to a research aircraft performing microburst penetrations. This test marks a milestone as being the first time that TDWR wind shear warnings were successfully transmitted and displayed in an aircraft in real-time. This effort was supported by NASA Langley Research Center as part of a program to investigate techniques for integrating airborne and ground-based wind shear information for aircrew alerting. The three main goals for 1990 were 1) to conduct microburst penetrations with an instrumented aircraft, 2) to compare a hazard estimate called the F factor (Bowles, 1990) for airborne and TDWR data, and 3) demonstrate real-time data link and cockpit display of TDWR warnings. All three of these goals were successfully carried out. The research aircraft, a Cessna Citation II operated by the University of North Dakota (UND) Center for Aerospace Sciences conducted over 80 microburst penetrations in Orlando over a six week period with TDWR testbed radar surveillance. Initial post-processing analysis in comparing the aircraft and TDWR F factors has begun. The cockpit display system was operated during the latter part of the flight test period, and proved useful in aiding the Citation crew in locating microburst and gust front events. There were three main objectives in the development of the cockpit display system. First, the real-time display was intended to aid the Citation crew in locating microburst and gust front events. This capability was desired both to aid the crew in locating events to penetrate, and to improve safety by providing a better information about the location of the wind shear events. A second objective was to demonstrate the feasibility of transmitting TDWR wind shear warnings to aircraft in real-time. This demonstration is an important element in the eventual development of an integrated aircrew alerting procedure incorporating both airborne and ground-based wind shear information. This study marks the first successful demonstration of real-time transmission of TDWR wind-shear warnings to an aircraft in flight. A third objective was to demonstrate the desirability of transmitting TDWR wind shear warnings to aircraft in real-time. Currently, the TDWR provides these warnings to controllers as textual messages, which are then relayed to pilots via voice communications. The TDWR also includes graphical displays of wind shear and precipitation products but these are only provided currently to the Tower and TRACON supervisors. A potential use of Mod S Data Link (or other ground-to-air data link systems) is to provide TDWR wind shear warnings directly to pilots, Automatic delivery of TDWR wind shear warnings potentially result in decreased controller workload and improved pilot information. Mode S Data Link is currently planned to provide textual wind shear warnings only. However, studies by Wanke and Hansman (1990) show that pilots substantially prefer graphical presentation of wind shear warnings over textual presentation. The paper will first describe the organization of the system, including the process of generating the display messages in the TDWR testbed and data linking them to the aircraft. Second, the display format and operation of the cockpit display will be described. Next, an example of the operational use of the cockpit display will be presented, along with initial F factor results. Finally, the paper will conclude with a summary and plans for future work.