Development of New Flight Test Techniques for Helicopter Air to Air Refueling Qualification Process

Abstract

© 2022, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Although there are literature references that detail guidelines and flight test techniques for Fixed Wing Air-to-Air Refueling (FWAAR), there are no well established methods to perform Helicopter Air-to-Air Refueling (HAAR). Straightforward application of those FWAAR methods neglecting specific helicopter performance and HQ characteristics did not demonstrate to be a successful approach, given that actual critical conditions for defining HAAR envelope could not be identified. Therefore, this work presents methods and techniques developed by the Brazilian Flight Test and Research Institute (IPEV) during the HAAR qualification process between the helicopter H225M and the tanker KC-130H. Results demonstrated that a more complete assessment for defining HAAR envelope could be performed when using a power margin approach for planning and performing flight tests. Literature CHR (Cooper-Harper Rating Scale) contact tasks for FWAAR based on precision performance criteria were then tailored in order to take into account low closure rate profiles and limited power margins. Additionally, given the limitations of the CHR assessment, a modified version of DIPES (Deck Interface Pilot Effort Scale), which is well-know for multi-axis evaluation in helicopter / ship qualification flight testing, was also applied when performing contact tasks. This approach allowed to identify unacceptable pilot workload levels more easily than the CHR. Therefore, this paper aims at presenting the lessons learned during planning, execution and data processing steps of the HAAR flight test campaigns in order to further enhance flight test techniques on that type of procedure.