Landing Period Designator Visual Helicopter Recovery Aide; Theory and Real-Time Application

Landing Period Designator (LPD), an application of Dynamic Interface (DI) studies, was developed to provide greater attention to the dynamic issues encountered by air vehicles on launch and recovery from a moving body. A review of the tools used to develop the LPD is made. The LPD is based on the evaluation of motion bearing energies collapsed into a scalar function called the Energy Index. The index, an empirical relation, evaluates shipmotion as a function of the air vehicle limits by a process of filters designed to determine the airvehicle responses at the instant of recovery. The theory, simulation, and at-sea testing programs of the LPD, are summarized. Particular attention is given to LPD responses under especially rigorous at-sea pilot-in-loop testing conditions. Filter modifications prompted by exposure to extreme environments, are discussed. LPD has been found to accurately represent safe deck in any sea condition. More importantly, LPD has been shown to correctly identify safe deck windows even in the most severe conditions. Application of the LPD as a tool in other DI taskings are considered. In particular, the incorporation of the LPD into the NSWC’s Active Operator Guidance (AOG) System as a navigational tool, is presented. AOG allows the establishment of an appropriate ship’s heading to acquire a desired shipmotion.