DataComm in flight deck surface trajectory-based operations

Continuous descent operations (CDOs) with required times of arrival (RTA) have been identified as a potential solution for reducing the environmental footprint of aviation in the terminal maneuvering area without compromising capacity. This paper assesses the feasibility of replacing current air traffic control sequencing and merging techniques, mainly based on path stretching and air holding, by a control based on RTA over metering fixes on known and fixed arrival routes. Because the remaining distance to the runway threshold is always known by the aircraft crew, this would allow engine-idle CDOs that do not require speed-brake usage and where only elevator control is used to meet the RTA. The assessment has been performed for Barcelona-El Prat Airport (Spain) using historical traffic demand data. The earliest and latest trajectories at a metering fix for each inbound aircraft were computed assuming engine-idle CDOs. Given the attainable RTA window for each aircraft, the aircraft sequencing problem was solved. The results show that assigning RTA allows optimizing the landing sequence when air traffic is low. For scenarios with high-traffic loads and late RTA assignments, path stretching still was found to be necessary. The minimum distance from the runway where inbound aircraft should receive the RTA to fully remove any radar vectoring was also analyzed. It was demonstrated that the assignment of RTA well before starting the descent would favor to enable full CDOs.

A ground-centric concept for merging and sequencing aircraft on Area Navigation (RNAV) and/or Required Navigation Performance (RNP) procedures in the terminal area leveraging the advanced flight deck capability of meeting required time of arrival (RTA) instructions is defined. Automation to provide time-based resolution advisories—RTAs, speed control, and lateral offsets (LOs)—to the controller to achieve efficient merging and sequencing is proposed. Closed-loop simulations using the proposed automation were conducted to assess the viability of the advisory heuristics and to examine coupling dependencies in multiple merge systems.

Next generation air transportation system (NextGen) concepts of operation may require aircraft to fly planned trajectories in four dimensions - three spatial dimensions and time. A prototype 4D flight management capability is being developed by NASA to facilitate the development of these concepts. New trajectory generation functions extend todaypsilas flight management system (FMS) capabilities that meet a single required time of arrival (RTA) to trajectory solutions that comply with multiple RTA constraints. When a solution is not possible, a constraint management capability relaxes constraints to achieve a trajectory solution that meets the most important constraints as specified by candidate NextGen concepts. New flight guidance functions provide continuous guidance to the aircraftpsilas flight control system to enable it to fly specified 4D trajectories. Guidance options developed for research investigations include a moving time window with varying tolerances that are a function of proximity to imposed constraints, and guidance that recalculates the aircraftpsilas planned trajectory as a function of the estimation of current compliance. Compliance tolerances are related to required navigation performance (RNP) through the extension of existing RNP concepts for lateral containment. A conceptual temporal RNP implementation and prototype display symbology are proposed.

This pap er presents the development and preliminary results of a trajectory analysis and modeling environment developed in MATLAB and applied to the study of the effects of navigation performance on arrival timing accuracy . This work supports ongoing efforts at The Boeing Company to develop new air traffic management (ATM) concepts and procedures based on accurate navigation standards such as Required Navigation Performance (RNP) and Required Time of Arrival (RTA) . The arrival management concept studied involves th e use of advanced ground automation that perform s sequencing and spacing based on FMS paths rather than relying on controller tactical vectoring . These paths can be defined in three dimensions from prior to top of descent (TOD) to the meter fix and then to the runway , potentially including speed and altitude constraints when needed and would be communicated to the air crew via voice communication and executed to standards (e.g. RNP, RTA) by t he air navigation function embedded in the Flight Management Syste m (FMS). This concept is viewed as a transition step towards the US next generation air traffic system currently being studied by the Joint Planning and Development Office (JPDO).

An Agent-Based Approach to Aircraft Conflict Resolution with Constraints

The Ration by Schedule (RBS) algorithm has been accepted by the aviation community as the basis of Collaborative Decision Making (CDM) in strategic Traffic Flow Management (TFM) initiatives such as Ground Delay Programs (GDPs) and Airspace Flow Programs (AFPs). However, applications of RBS to date have been limited to strategic metering applications in which the slots to be allocated to flights are all of equal duration, and the flights to be assigned to slots do not need to be differentiated. Decision support capabilities for the general Air Traffic Management (ATM) problem require planning and scheduling algorithms that properly recognize different flight characteristics such as weight class, runway, departure direction and other Air Traffic Control (ATC) procedural issues in determining the slot size that is required for each flight. In this paper, we describe our design and implementation of the Generalized RBS algorithm for a surface traffic management scheduling application which involves detailed flight-by-flight slot time assignment. This algorithm has been designed and developed to support the Collaborative Departure Queue Management (CDQM) component of the Surface Trajectory Based Operations (STBO) project. CDQM provides an equitable allocation of departure capacity to each flight operator at an airport for dynamic use in management of departure queues. The principles of the RBS algorithm are achieved through an initial planning pass based on scheduled data, followed by a second planning pass in which dynamic flight status is incorporated into the planning results.

At airports sustaining commercial operations, Runway Incursions, defined as the incorrect presence or manoeuvre of an aircraft, vehicle or person on a runway, constitute the most severe hazard to flight safety. In fact, the worst-ever accident in civil aviation to date, the collision of two Boeing B747s on Tenerife in March 1977 with 583 fatalities, was caused by a Runway Incursion. As early as 1986, a special investigation report of the National Transportation Safety Boards (NTSB), which is responsible for investigating aviation incidents and accidents in the USA, concluded that Human Factors issues and not technical malfunctions were the primary causal factors of Runway Incursions. This is remarkable, because although surface movement is one of the most challenging cockpit tasks, pilots are currently not supported by sophisticated assistance systems in this critical phase of flight, but still mainly rely on visual acquisition of their environment and Air Traffic Control (ATC) instructions conveyed via radio. The only mandatory additional equipment consists of paper charts, compass and Notices to Airmen (NOTAM). Consequently, the goal of this thesis is to investigate to what extent Runway Incursions can be attributed to an inadequate presentation or lack of required information on the flight deck, and how flight deck instrumentation will possibly have to be supplemented in order to increase safety in the airport environment. Following a scrutiny of current procedures for surface movement with respect to potential deficiencies, an in-depth analysis of 40 incidents and accidents is conducted to identify and categorize generic, recurring causal factors of Runway Incursions. Apart from several exceptions that can be attributed to incorrect ATC instructions or clearances, results clearly indicate that the investigated Runway Incursions were primarily caused by a lack of pilot situation awareness. The underlying reasons are a lack of suitable navigation aids, missing means of acquiring the surrounding traffic including potential conflicts, insufficient presentation of information on the airport operational environment (such as closed or restricted runways) or misunderstandings in the communication with ATC. In order to address these deficiencies, a holistic flight deck visualisation and warning concept based on Airport Moving Map (AMM) technology, an already commercially available database-driven electronic airport chart presentation, is developed in the frame of this thesis, integrating all of the information required for Runway Incursion avoidance in an intuitive fashion. In case the mere presentation of information is not sufficient to prevent a hazardous situation, e.g. due to the dynamics of an emerging traffic conflict, pilots are alerted in a manner consistent with current flight deck alerting systems. A prototypic realisation of the resulting onboard surveillance system is validated with airline pilots in field trials at Frankfurt and Prague airport, using a Navigation Test Vehicle, followed by a further evaluation campaign employing a Research Flight Simulator.

Over the last decade there has been considerable development of the applications of modern technology to the avionics of new aircraft. Examples of this have been the provision of area navigation and flight management systems, and now with the advent of cathode ray tube displays there is the opportunity to provide a greater range of information to the pilot in a more readily assimilable form than is at present possible. There have been similar developments in computer assistance to air traffic control (ATC) to aid the ground controller. There has, however, been a tendency for these and other parts of the operational system to be improved without fully evaluating their interaction with each other, especially the interaction between ATC and the flight deck. Unless this aspect is studied it is probable that the full capability of the system with its potential for improving the safety and economy of operation will not be fully realized.The Civil Avionics Section of Operational Systems Division at RAE Bedford, in collaboration with UK avionics manufacturers and funded by the Department of Industry, has been concerned for a number of years with the development and integration of these systems in the flight deck of the future and with the way in which they can be used to develop, in conjunction with ATC, an improved system of air traffic management.

Although established some 60 years ago voice communications is still the sole means to separate and guide aircrafts. Voice communication systems are therefore amongst the most critical installations in air traffic control (ATC). Frequentis was the first to introduce PCM (pulse code modulated) based equipment for ATC worldwide and is on the leading edge of steering into the world of packetized voice communications. VoIP is the emerging voice communication technology which has already proven to provide satisfactory service for commercial applications. However, in ATC a number of requirements exceeding commercial applications have to be met. The voice communication system for ATC integrates radio communication as a prime service. Delays generated by the system therefore directly affect the performance on the radio channel and need to be extremly low. Both the radio control (push-to-talk, PTT) and the voice content need to be processed and delivered in a timely manner. SIP (session initiated protocol) based signalling represents a promising approach to tackle the delay problem. In addition, voice communication systems are required to provide high availability figures. VoIP based systems strongly rely on the communications infrastructure as they are distributed by nature. Resilient packet ring structures allow for these high availablity figures for the communications infrastructure.

An ATC (Air Traffic Control) experiment using ETS-V (Engineering Test Satellite V) was conducted. In the experiment, the position of aircraft was measured by CIS (Cooperative Independent Surveillance) and ADS (Automatic Dependent Surveillance). Data communication and voice communication using NBFM and LPC between ground and air was conducted. The result shows that the positioning accuracy of CIS and ADS is enough to minimize present oceanic separation of aircraft. More than 95% of the controllers participated in the experiment evaluated the quality of voice communication using NBFM as bettr than that of present HF communication. Also 81% of them prefer LPC to HF. An error rate of received characters on aircraft through data communication is less than 2×10^<-4>, which shows that the satellite data link has the possibility of improving oceanic ATC capability.

Adapting a Human – Automation Trust Scale to an Air Traffic Management Environment

An Eulerian network model for air traffic flow in the National Airspace System is developed and used to design flow control schemes which could be used by Air Traffic Controllers to optimize traffic flow. The model relies on a modified version of the Lighthill-Whitham-Richards (LWR) partial differential equation (PDE), which contains a velocity control term inside the divergence operator. This PDE can be related to aircraft count, which is a key metric in air traffic control. An analytical solution to the LWR PDE is constructed for a benchmark problem, to assess the gridsize required to compute a numerical solution at a prescribed accuracy. The Jameson-Schmidt-Turkel (JST) scheme is selected among other numerical schemes to perform simulations, and evidence of numerical convergence is assessed against this analytical solution. Linear numerical schemes are discarded because of their poor performance. The model is validated against actual air traffic data (ETMS data), by showing that the Eulerian description enables good aircraft count predictions, provided a good choice of numerical parameters is made. This model is then embedded as the key constraint in an optimization problem, that of maximizing the throughput at a destination airport while maintaining aircraft density below a legal threshold in a set of sectors of the airspace. The optimization problem is solved by constructing the adjoint problem of the linearized network control problem, which provides an explicit formula for the gradient. Constraints are enforced using a logarithmic barrier. Simulations of actual air traffic data and control scenarios involving several airports between Chicago and the U.S. East Coast demonstrate the feasibility of the method.

In 2017 and 2018, under National Aeronautics and Space Administration (NASA) sponsorship, the New York Unmanned Aircraft Systems (UAS) Test Site and Northeast UAS Airspace Integration Research (NUAIR) Alliance conducted a year-long research project that culminated in a UAS technology flight demonstration. The research project included the creation of a concept of operations, and development and demonstration of UAS technologies. The concept of operations was focused on an unmanned aircraft transiting from cruise through Class E airspace into a high-density urban terminal environment. The terminal environment in which the test was conducted was Griffiss International Airport, under Syracuse Air Traffic Control (ATC) approach control and Griffiss control tower. Employing an Aurora Centaur optionally piloted aircraft (OPA), this project explored six scenarios aimed at advancing UAS integration into the National Airspace System (NAS) under both nominal and off-nominal conditions. Off-nominal conditions were defined to include complete loss of the communications link between the remote pilot’s control station on the ground and the aircraft. The off-nominal scenarios that were investigated included lost-link conditions with and without link recovery, an automated ATC initiated go-around, autonomous rerouting around a dynamic airspace obstruction (in this case simulated weather), and autonomous taxi operations to clear the runway.

Carrying out a safe approach under fluctuating wind and weather conditions while following air traffic control (ATC) instructions imposes a significant workload on the flight crew, especially with the limited systems support and information availability on the flight deck today. Individual skills of the pilots including correct anticipation of the weather situation and ATC instructions are necessary to optimally manage speed and configuration changes of the aircraft. Consequently, approach operations at busy airports are virtually always noisier and less fuel-efficient than technically possible. The DYNCAT project combined all relevant data sources (on-board operational data, ATC commands, noise measurement data, surrounding traffic, and weather information) to evaluate individual approach operations in their full context, exemplarily for the Airbus A320 at Zurich airport. Based on this analysis, an operational concept was developed to support pilots and controllers through extended information exchange, thus increasing predictability of the lateral and vertical flight profiles for both sides. A central component is a novel airborne energy management assistance system including a configuration management functionality, implemented through an extension of the Flight Management System (FMS) and Cockpit Display System (CDS) capabilities. These features were evaluated regarding operational (pilots’ workload and situational awareness) and environmental (fuel burn and noise exposure levels) improvements through piloted simulator trials on a fixed-based test bench. The present partial and initial implementation of the functions for the Airbus A320 family evaluates favourably with respect to the above criteria when compared with the state of the art, i.e., support by current FMS functions.

Air transportation is an important factor for the economic growth of the European Union, however, the current system is already approaching its capacity limits and needs to be reformed to meet the demands of further sustainable development (Commission of the European Communities, 2001). These limitations stem mainly from the current European air traffic control system. Air traffic control within Europe is fragmented due to political frontiers into regions with different legal, operational, and regulative contexts. This fragmentation decreases the overall capacity of the European air traffic control system and, as the system is currently approaching its capacity limits, causes significant congestion of the airspace. According to the European Commission airspace congestion and the delays caused by it cost airlines between €1.3 and €1.9 billion a year (European Commission, 2011). For this reason, the European Commission agreed to adopt a set of measures on air traffic management to ensure the further growth and sustainable development of European air transportation. The key enabler of this transformation is the establishment of a Single European Sky1 (SES). The objective of the SES is to put an end to the fragmentation of the European airspace and to create an efficient and safe airspace without frontiers. This will be accomplished by merging national airspace regions into a single European Flight Information Region (FIR) within which air traffic services will be provided according to the same rules and procedures. In addition to the fragmentation of the airspace the second limiting factor for the growth of European air transportation lies within the legacy Air Traffic Control (ATC) concept. In the current ATC system, which has been developed during the first half of the twentieth century, aircraft fly on fixed airways and change course only over navigation waypoints (e.g. radio beacons). This causes non-optimal paths as aircraft cannot fly directly to their destination and results in a considerable waste of fuel and time2. In addition, it concentrates aircraft onto airways requiring ATC controllers to ascertain their safe separation. The tactical control of aircraft by ATC controllers generates a high demand of voice communication which is proportional to the amount of air traffic. As voice communication