The main aim of the DLR-internal project flexiGuide is the creation and introduction of more individual and flexible approach procedures to reduce environment impacts. In the past, different theoretical approaches for the reduction of fuel consumption, aircraft noise, and air pollution were developed. Through a combination of modern 4d flight management systems, data link connections, optimized approach routes and procedures, and a broad sequence planning and trajectory negotiation support for arrival and departure controller, these technologies enable continuous descent operations (CDO) on busy airports even at peak traffic hours. The flexiGuide concept expands the conventional Standard Instrumental Arrival Routes (STAR) and transitions by a Late Merging Point (LMP) on each final, roughly positioned on the half way between Final Approach Fix (FAF) and runway threshold. Military restricted areas, severe weather zones, individual approach routes, and many more methodologies are considered when aircraft merge at final joint airspace points.
The approaching flight traffic will be operational divided in conventional arrivals and flights implementing continuous descent operations. Appropriate equipped aircraft are permitted on the one hand to use an individual aircraft optimized approach procedure like continuous descent approach (CDA), and on the other hand perform a conflict free short cut from transitions to LMP and threshold. The modified airspace structure from flexiGuide enables an increased flexibility as a response on varying traffic and adverse meteorological conditions. This includes limited adjustable standard arrival routes in an Extended Terminal Manoeuvring Area (E-TMA), which enable controller to guide less equipped aircraft on preferred direct routes in low and medium volumes of traffic. Extreme weather conditions may have an influence on approach routing.
Additionally, meteorological impact on noise dissemination and raised air navigation requirements during reduced visibility conditions have to be included. Using continuous descent operations during approach procedures meteorological constraints have to be included because of the direct and indirect influence of wind-dependent sound propagation. A flexible airspace structure may help to avoid aircraft noise because during night times other approach routes are valid than during daylight at some airports. In addition to route adaption the optimization of individual approach procedures are promoted in the project with the aim, to use the full capacity of the noise reducing potential.
One key issue on the way to a flexible and time based aircraft guidance concept is the support of controller and pilots with tactical assistance systems, which have to provide much more sophisticated support functionalities than today. Various air traffic controller support functions were integrated whereas most of them embody optical support elements for time based flight guidance. The experience of the DLR-project “Future Air Ground Integration” (FAGI) showed the importance of timely precise turn-to-base navigation. For example every delay on the downwind is doubled on the centerline when flying on the trombone pattern.
The planning and management systems should use partly automated air-ground target-time and trajectory negotiation and have to integrate the negotiation results into the aircraft arrival scheduling. Additionally controllers get planning and visual support for guiding conventional air traffic during approach and taxiing. The consideration of complex weather situations will be implemented in the supporting systems as well the latest scientific results from sleep research. As part of the project the concept will be validated with the help of fast-time, real-time, and human-in-the-loop simulations on the example of todays and future air traffic scenarios at real airports.