Rotary Wing Aircraft Maneuver Recognition Algorithm Development and Validation Approach

The rotary wing aircraft usage spectrum is derived from AR-56 requirements and consists of maneuvers performed by helicopters in order to accomplish their missions. The Health and Usage Monitoring System (HUMS) recorded data can be utilized to develop usage spectrum for each aircraft using the maneuver recognition algorithm. Furthermore, usage from individual aircraft, in association with the previously established component damage rate, can be used to determine Condition Based Component Replacement (CBCR) time. To implement CBCR, the development of reliable maneuver/regime algorithm is necessary. There are regime recognition programs developed by Original Equipment Manufacturers (OEM’s) and recorder manufacturers with different approaches. At present, there are no standards to determine the reliability of regime recognition and its validations. Over the past 17 years, the U.S. Navy (USN) has fielded structural data recording systems on H-1, H-3, H-46, H-60, H-53, and V-22 rotary wing aircraft and recorded flight parameters and used them to recognize regimes. The aeromechanic flight state parameters based regime recognition software development approach is detailed in this paper. The program developed recognizes almost 97% of maneuvers indicated by pilots. In addition, the program identifies almost all maneuvers in a flight load survey. Therefore, the recognized regime damage rate is equal to or greater than the flight load survey regime damage rate. Control stick positions are used to recognize control reversals but not maneuvers. Thus, maneuver recognition is independent of pilot technique. Based on the experience of regime recognition development for various USN rotary wing aircraft, different approaches to validate and determine the reliability of regime recognition software have been suggested. The concept of positive, negative, and surrogate recognition has been introduced.