The background and rationale for the research reported in this paper is detailed in the companion paper subtitled Part A: Modelling the on-deck helicopter Reserve of Stability (ROS).This paper (Part B) derives the fundamental principles underpinning the safe operational envelope and the definition of Motion Severity and Wind Severity Indices (MSI/WSI), and then presents the probabilistic modelling methodology developed for calculating safe limits for these parameters (MSI/WSI limits curves). The introduction of the Relative Wind Direction (RWD) as an additional limiting parameter is also discussed, together with an explanation of how RWD limits have been derived and how they are linked with the MSI/WSI limits calculation.The MSI/WSI limits modelling methodology presented in this paper builds on the analytical helicopter stability modelling discussed in Part A. It uses a probabilistic approach to manage the variability in helicopter operations across the UK and to deal with the uncertainty of predicting helideck motion and wind conditions for the period the helicopter is landed on the helideck based on measurements taken prior to landing. This has been developed with the assistance of industry experts and has been subjected to consultation with stakeholders in the UK with the aim of identifying the right balance between enhancing safety and preserving operability.A new Helideck Monitoring System (HMS) standard has been developed which incorporates the MSI/WSI/RWD functionality. The standard was published by the Helideck Certification Agency in April 2018 with a compliance date of 31 March 2021. Operations to moving decks not equipped with HMS meeting the new standard will be restricted to stable helideck conditions.

中文翻译：

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CAA 研究计划 - 将直升机运营转移到海上直升机平台

本文报告的研究背景和基本原理在副标题为 A 部分：模拟甲板上直升机稳定性储备 (ROS) 的配套论文中进行了详细说明。本文（B 部分）推导了支持安全操作包络和运动严重性和风力严重性指数 (MSI/WSI) 的定义，然后介绍了为计算这些参数的安全限制而开发的概率建模方法（MSI/WSI 限制曲线）。还讨论了将相对风向 (RWD) 作为附加限制参数的介绍，并解释了如何导出 RWD 限制以及它们如何与 MSI/WSI 限制计算联系起来。本文介绍的 MSI/WSI 限制建模方法建立在 A 部分讨论的直升机稳定性分析模型的基础上。它使用概率方法来管理英国直升机运营的可变性，并处理预测直升机甲板运动和风的不确定性根据着陆前进行的测量，直升机在直升机停机坪着陆期间的条件。这是在行业专家的协助下开发的，并与英国的利益相关者进行了磋商，目的是在提高安全性和保持可操作性之间找到适当的平衡。已开发出新的直升机甲板监控系统 (HMS) 标准，其中包含MSI/WSI/RWD 功能。