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Evaluation of the C/EC/KC-135 Ground Collision Avoidance System (GCAS) (Study 2)

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Final rept. 1 Feb-30 Apr 1992

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This report represents the second of a two-study evaluation program. The first study Rueb and Hassoun, 1991 evaluated the original Cubic GCAS algorithm in four distinct phases. Throughout the four phases, concerns and recommendations were forwarded to the System Program Office and to the Cubic Corporation. This resulted in modification of the algorithm prior to the next phase of the evaluation. Phase I efforts focused on the verification and validation of the algorithm. This phase simply established how well the algorithm predicted altitude loss based on current inputs. Phase II was the robot pilot model phase. During this phase, a computer pilot model tested the GCAS under different aircraft configurations and environmental conditions. The man-in-the-loop phase, Phase III, used a subset of the configuration in Phase II in addition to a series of Instrument Landing System ILS runs to determine algorithm ability to accurately predict under realistic conditions human reaction times. In the final phase, current operational pilots flew mission scenarios based on selected CFIT mishaps. This phase permitted an evaluation of the Cubic GCAS algorithm under real-world conditions. Study 2 used the same four-phase approach as that used during Study 1. However, the evaluation was performed on the newly revised Cubic algorithm. The revised algorithm incorporated more extensive changes than those conducted after each of the Study 1 phases. Additionally, Study 2 evaluated Phase 1 - Phase 4 without any delay. Unlike Study 1, the algorithm was not returned to Cubic for modification prior to the next phases.

Subject Categories:

  • Military Aircraft Operations
  • Transport Aircraft
  • Military Operations, Strategy and Tactics
  • Human Factors Engineering and Man Machine Systems
  • Bionics

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