William J. Penhallegon

Considerations for Interval Management Operations in a Mixed-Equipage Environment

Interval Management (IM) encompasses an evolving set of applications that enable more precise and consistent spacing between aircraft to yield increased throughput and efficiency in the National Airspace System. Most IM applications contain relative (flightdeck) and absolute (ground-based) components. Relative spacing relates the position of an aircraft in a stream to its preceding aircraft and is different from absolute spacing, where spacing is achieved by independently controlling aircraft to a specified point-inspace at a desired time. The flight-deck component consists of avionics that provide speeds to the flight crew to achieve and maintain a desired spacing interval relative to a target aircraft. The ground-based component helps controllers initiate the flight-deck operation and also provides air traffic controllers with speed advisories to manage the unequipped aircraft to absolute scheduled times of arrival at a specified point. In a mixed-equipage IM environment, where both of these components are used to manage the spacing of equipped and unequipped aircraft, the relative spacing flight-deck component and absolute spacing concept for the ground-based component are combined into a single operation. This paper addresses some of the challenges and considerations for the mixed-equipage operation, including performance differences in the two concepts and scheduling considerations that could be developed to increase system benefits. The results of this paper may help to drive decision-making for implementing IM in a mixed-equipage operation. Results also suggest that in many cases the relative spacing concept provides operational throughput benefits over the absolute spacing concept.

En-route flight deck-based merging and spacing impact on flight crew operations

In an effort to achieve consistent, low variance spacing between aircraft pairs during arrival operations and to reduce aircraft maneuvering, noise, fuel burn, and controller workload, the Federal Aviation Administration (FAA) is developing, and UPS plans to implement, an Automatic Dependent Surveillance-Broadcast (ADS-B) concept termed Merging and Spacing (M&S). M&S has two phases: a strategic set-up by a ground operator followed by tactical Flight Deck-Based Merging and Spacing (FDMS). Both phases, in the initial implementation, involve pilots being requested to fly speeds from sources other than Air Traffic Control (ATC). In FDMS, the speeds are generated and displayed on-board the aircraft via a Cockpit Display of Traffic Information (CDTI) or other display. The flight crew follows those speeds to achieve a desired time interval from a lead aircraft. This paper focuses on FDMS and presents the subjective and objective results of a human-in-the-loop simulation that examined FDMS from the flight crew perspective during a merge in the en-route environment. Termed FDMS 2, the simulation is part of a development and maturation process that is underway for FDMS. The simulation examined the impact of FDMS on: concept and display acceptability; workload and situation awareness; and procedures for non-normal situations. Ten airline-qualified pilots flew a series of scenarios while acting as the pilot flying. Results indicated general acceptability and improvements over current-day operations under normal and non-normal conditions. Pilots, on average, found the number of speed commands acceptable and their traffic awareness to be improved. They reported a small and acceptable increase in workload over current conditions. The majority of pilots reported concerns about the location of the CDTI, but all agreed that having the display in the experimental location was preferable to not having it and not being able to conduct FDMS. It was also found that pilots may have been driven to spend higher amounts of time viewing a display to detect situations that normally would be resolved by ATC. These results will be used to further refine FDMS and to focus future simulations as the application moves toward operational approval.

Flight Deck-Based Merging and Spacing impact on flight crew operations during Continuous Descent Arrivals and approaches

In an effort to achieve consistent, low variance spacing between aircraft pairs during arrival operations and to reduce aircraft maneuvering, noise, fuel burn, and controller workload, the Federal Aviation Administration (FAA) is developing, and UPS has implemented an Automatic Dependent Surveillance-Broadcast (ADS-B) concept termed Merging and Spacing (M&S). M&S has two phases: a strategic set-up by a ground operator followed by tactical Flight Deck-Based Merging and Spacing (FDMS). In the initial implementation, both phases, involve pilots being requested to fly speeds from sources other than Air Traffic Control (ATC). In FDMS, the speeds are generated and displayed on-board the aircraft via a Cockpit Display of Traffic Information (CDTI) or other displays. The flight crew follows those speeds to achieve and maintain a desired time interval from a lead aircraft. This paper focuses on FDMS and presents the subjective and objective results of a human-in-the-loop simulation that examined the concept from the flight crew perspective during an in-trail operation in the en route and terminal environments, from a Continuous Descent Arrival (CDA) through to landing. Termed FDMS 3, the simulation was conducted in February and March of 2007 and is part of a development and maturation process that is underway for FDMS. The simulation examined the impact of FDMS on: concept and display acceptability; workload and situation awareness; and procedures for non-normal situations. Nine airline-qualified pilots flew a series of scenarios while acting as the pilot flying. Results indicated general acceptability and improvements over current-day operations under normal and non normal conditions. Pilots in general reported that FDMS: was acceptable, was compatible with current operations, was similar in terms of workload as compared to operations without FDMS, allowed for a reduction in communications with ATC, and allowed for acceptable situation awareness. Pilots were able to use the displays to implement speed changes to manage normal and non-normal situations such that the desired spacing interval was maintained with minimal variation. Some pilots reported issues with the CDTI retrofit location and reported increased acceptability of FDMS when the CDTI location was moved to the primary field of view. The simulation results related to the concept were used to further refine FDMS and to focus future simulations. They also supported an implementation that was certified and operationally approved.

Interval Management: Development and Implementation of an Airborne Spacing Concept

Interval Management is a suite of ADS-B-enabled applications that allows the air traffic controller to instruct a flight crew to achieve and maintain a desired spacing relative to another aircraft. The flight crew, assisted by automation, manages the speed of their aircraft to deliver more precise inter-aircraft spacing than is otherwise possible, which increases traffic throughput at the same or higher levels of safety. Interval Management has evolved from a long history of research and is now seen as a core NextGen capability. With avionics standards recently published, completion of an Investment Analysis Readiness Decision by the FAA, and multiple flight tests planned, Interval Management will soon be part of everyday use in the National Airspace System. Second generation, Advanced Interval Management capabilities are being planned to provide a wider range of operations and improved performance and benefits. This paper briefly reviews the evolution of Interval Management and describes current development and deployment plans. It also reviews concepts under development as the next generation of applications.

Multi-Purpose Cockpit Display of Traffic Information: Overview and Development of Performance Requirements

This paper describes a Multi-Purpose Cockpit Display of Trac Information (MPCDTI), which integrates core functional capabilities that can be combined in various ways to perform ADS-B In applications in the NextGen environment. The MPCDTI is dierent from other CDTIs in that it packages the capability to manage multiple applications within a single piece of equipment. Four key elements of the MPCDTI have been dened: elemental functions, simultaneous enablement, automatic algorithm selection, and output arbitration. These elements allow compatible functions to be enabled and prevent the MPCDTI from outputting infeasible or conicting guidance to the ight crew. The objectives of this paper are to present the key features of the MPCDTI and also to suggest a functional approach for developing MPCDTI and future application performance requirements.

Communication of Target Trajectory and Wind Information to Improve Airborne Interval Management Spacing Performance

Interval Management (IM) is an ADS-B-enabled NextGen concept that will lead to more precise inter-aircraft spacing between an IM Aircraft and a Target Aircraft, in order to increase runway throughput. This paper describes the integration of IM operations with time-based metering operations and the related ground automation, which will support air traffic controllers in managing mixed operations (i.e., some aircraft are equipped with IM avionics and some are not). There are several considerations when determining how IM operations should be integrated into the time-based metering environment, including the initiation location and the information that must be communicated to the IM avionics to conduct the IM operation. This paper examines some performance trade-offs between where to initiate IM and the extent to which communication of supporting trajectory and wind information is needed. Starting the IM operation far from the destination runway requires more information about the environment in order to ensure that the desired spacing precision can be met, but is less sensitive to the pre-conditioning of the traffic at initiation. Conversely, initiating IM closer to the runway requires less information to be provided to the IM Aircraft; however, it requires more consistent traffic pre-conditioning prior to initiation. The performance trade-offs discussed here will be used as input to the development of Data Communications messages, which can enable the transfer of more complex operational and environmental information between air traffic control and flight crews and/or avionics to improve IM performance.