Flight Test Results NH90 NFH Helicopter-Ship Qualification Process

Whilst the aircraft itself is always limited to operations within its service release envelope, and may be cleared for ships, each unique ship/helicopter combination needs to be explored in an appropriate manner. The helicopter-ship qualification process consists initially of shore-based hover trials to document the low speed flight characteristics, as a function of referred weight and relative wind condition, and these data will be combined with airwake data for each ship type to develop the so-called "candidate flight envelope". This candidate flight envelope will be (partially) validated during sea trials for each ship type. The goal of the present paper is to present predictive engineering tool, the so-called "SHOL-X", to be used in the qualification process to perform early evaluation of safety limits for operating aircraft from ships. In this way, the qualification process can be less dependent on the results from several dedicated sea trials. The predictive tool thereby not only reduces time and cost of the test campaign, but also improves the accuracy of the finally determined operational envelope used for in-service operation for many years to come. The paper will describe the "SHOL-X" tool applied to the flight test results for the NH90 NFH helicopter-ship qualification process conducted in The Netherlands on the landing platform dock "Hr.Ms. Rotterdam".