Development of green curved IFR rotorcraft procedures relying on GNSS
For a long time, IFR rotorcrafts have been using the same procedures designed for fixed-wing aircraft and were forced to use runways. Furthermore, until recently, no GPS-based IFR approach had ever been designed for helicopter operations in Europe. Such paths requiring high-precision guidance enable rotorcraft to avoid noise-sensitive urban areas. The CARE (Curved Applications for Rotorcraft Environmental enhancement) project built on the success of another EU-funded project, GARDEN (GNSS-based ATM for Rotorcraft to Decrease Noise), obtaining a complete overview of the benefits offered by IFR rotorcraft procedures relying on GNSS and SBAS. In particular, steep and curved trajectories are key enablers for the implementation of simultaneous non-interfering (SNI) aircraft-rotorcraft operations. CARE was initiated to support the design and implementation of new procedures to help rotorcraft access busy airports independently of other aircraft using low-noise flight paths as well as facilitate operations in mountainous areas. The new flight profiles for rotorcraft air traffic management are designed to meet the objectives of Clean Sky, the EU's ambitious aeronautical research programme. For this two-year project CleanSky JU has selected a consortium led by Egis Avia and formed by the French air navigation service provider (DGAC/DSNA), Pildo Consulting and CGX Aero. The Performance-Based Navigation manual (ICAO Doc 9613) served as a basis for the analysis of the regulatory baseline supporting the development of this new procedure. Applicability of different curved segments concepts currently defined regarding rotorcraft needs and flight phases were highlighted in the frame of the project. Moreover, other innovative concepts such as curved final approach segment data block or curved terminal area path data block were also addressed. Researchers drafted design criteria for RNP 0.3 RNP APCH (LPV) and RNP AR navigation specifications for three different cases: Curved rotorcraft approach under full SBAS guidance with straight-in final approach (RNP AR or LPV); curved rotorcraft approach under full SBAS guidance with curved final approach (RNP AR or LPV) and curved rotorcraft PinS approach under full SBAS guidance. SNI operation constraints and noise minimisation were the main drivers for defining these procedures. GNSS-SBAS guidance enhances precision and performance of rotorcraft navigation. In particular, curved procedures enable rotorcraft to operate under IFR in challenging environments such as mountainous areas and to safely fly steep approaches to airports or helipads that are difficult to access or are located in densely populated areas. This is particularly important for many applications ranging from medical air transport to operations in the vicinity of airports that require no interaction with fixed-wing aircraft traffic. The results of the CARE and GARDEN projects were presented in November 2015 during a final event (User Forum) in Toulouse.
Keywords
Rotorcraft, flight paths, instrument flight rule, GNSS, SBAS, curved applications, PBN, low noise
