Improving Deceleration Guidance for Rotorcraft Brownout Landing

This paper details development and testing of a new speed guidance algorithm for the BrownOut Symbology System (BOSS), which is a display used for decelerating rotorcraft approaches in brownout conditions. The previous algorithm used in BOSS had two main issues that warranted design changes: (1) it was not robust in its ability to handle varying initial approach parameters, and (2) pilots from earlier brownout flight tests commented that the algorithm caused the aircraft to spend long amounts of time in brownout. Therefore a new speed guidance algorithm was developed that was capable of providing more consistent guidance from various starting positions and velocities. By manipulating a parameter within the algorithm, four variations of the algorithm were created with varying in levels of deceleration aggressiveness. A piloted simulation was conducted to evaluate these four algorithms against two approach types. Results found that one of the new algorithms provided a significant reduction in brownout time by over 20% and also received the highest preference ranking and highest comfort ratings.