“Tunnel in the Sky” Guidance for Helicopter IFR steep and curved approaches

Abstract

The European project OPTIMAL (Optimised Procedures and Techniques for IMprovement of Approach and Landing) is aiming to define and validate innovative procedures for the approach and landing phases of aircraft and rotorcraft in a pre-operational environment. The Institute of Flight Guidance of the German Aerospace Center in Braunschweig is also involved in this EU project with the objective to demonstrate the rotorcraft system’s 4D flight guidance capabilities. The present HMI solution is based on a head-down primary flight display (PFD). The PFD symbology incorporates a “tunnel-in-the-sky”-style visualization and has proven to render valuable assistance to the flight crew especially during complex manual flight manoeuvres (e.g. acceleration/deceleration requirements during fixed-radius turns while operating under wind influence). Additional guidance indications for heading, speed and altitude symbolized by green triangles have been integrated into the pilot display. The OPTIMAL results are expected to contribute to the development of ICAO design criteria for rotorcraft-specific Localiser Precision / Vertical guidance (LPV) approaches which are today in the agenda of the Helicopter Group of the Instrument Flight Procedures Panel (IFPP). The paper will provide an analysis of the flight results.