21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-6.7.2

EVALUATION OF WINDSHEAR HAZARD DISPLAYS AND GO-AROUND PROCEDURES USING PILOTED SIMULATIONS AT NLR

Haverdings H., Rouwhorst W. F. J. A.
National Aerospace Laboratory NLR, The Netherlands

Keywords: windshear, hazard displays, go-around procedures, piloted simulations

Two piloted simulation experiments were conducted by NLR, in 1994 and 1996, to evaluate a number of novel windshear icon displays, driven either by a scanning laser (1994) or by an Airborne Doppler (weather) Radar (ADR) (1996). In addition several flight procedures of coping with the windshear threat information were also evaluated., in terms of speed additives (1994) or aircraft configuration changes (1996). In the experiment of 1994 also the concept of speed feedback was evaluated: this concept raised the alert thresholds used to warn the crew of windshear whenever the pilot increased the approach speed set in the Autothrottle. This speed feedback concept, although initially appreciated much by the pilots, was later denounced due to its tendency to induce crews to penetrate the windshear. The windshear icon displays evaluated were liked very much by the pilots. Especially the ADR was favored because of its "natural" interface in the cockpit, allowing pilots to correlate weather information with windshear information. Its drawback of not being useful in case of "dry" microbursts (MBs) becomes less significant the lower the (dBZ) level becomes at which precipitation can still be detected. Integrating the ADR with the reactive sensor was found to be a good protection feature, provided a careful tuning of alert thresholds is done between the two systems. It may even be advisable to not suppress the caution alert from the reactive sensor when combined with the ADR Overall the icon displays had a positive effect on situational awareness and on flight safety. The crew's workload sometimes increased with the display, however, depending upon the weather situation. In some cases it was the workload of the pilot not flying which increased more than that of the pilot flying, especially during turning escape maneuvers to avoid windshear in the go-around.

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