Kapitel 3.1 Crosswind Operations

Abstract

: Crosswind operations rely on the simple effect that sufficiently strong crosswinds may transport wake vortices out of the flight corridor which may support temporary suspension of the need to apply wake turbulence separations between successive aircraft. CROPS (CRosswind OPerationS) is a EUROCONTROL funded project focused on runway use optimisation by the conditional reduction of wake turbulence distance-based separation minima between arrivals on final approach by taking advantage of the effect of crosswind on the wake turbulence decay and transport, while maintaining an acceptable level of safety regarding possible wake vortex encounter (WVE). It is a natural follow-on of the completed R&D project CREDOS (Crosswind REduced separations for Departure OperationS). The main driver of CROPS is congestion at major airports and fixed ICAO separations (not weather dependent). The scope of the CROPS project is currently limited to determination of crosswind conditions for a safe 0.5NM reduction of WT separations applied on final approach segment. This is done mainly by analysis of collected wake vortex and MET data. The results of this analysis form part of the key evidence in the safety assessment report. Although the CROPS concept of operations for a specimen operational environment relies on current ATM procedures, without a priori need of developing specific new ATC tool, the necessary changes to ANS/ATM system to allow operational application of CROPS will need to be assessed at local implementation level. It depends on the local ATM system in place and its performance, in particular regarding wind nowcast and forecast information. NATS incorporated the concept of operations for CROPs for arrivals within the scope for ‘Reduced Final Approach Separation’ (RFAS). RFAS considers both minimum headwind and crosswind component requirements for a 0.5NM separation reduction to selected wake constrained arrival pairs at Heathrow.