Peter M. Moertl

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.

An Operational Concept and Evaluation of Airline Based En R oute Sequencing and Spacing

** This paper describes an operational concept for airline operations centers (AOC) to implement desire d arrival sequences and spacing over an en route arrival merge fix . The paper reports the results of an initial field -test. The operational concept is termed Airline Based En route Sequencing and Spacing (ABESS). ABESS allows the AOC to set up arrival fl ows for transition into advanced flight procedures such as Continuous Descent Arrivals (CDAs) or Flight Deck -Based Merging and Spacing (FDMS) using flight -deck equipage with ADS -B capabilities. ABESS allows the AOC to shape arrival stream and spacings via an up link of direct speed advisories. This operational concept received an initial evaluation during a field test at the UPS AOC in Louisville Kentucky in October 2006. The results of this initial evaluation indicate the feasibility of the procedures an d identify software, accuracy, and procedural requirements for concept implementation.

Field test results of an airline based en route sequencing and spacing tool

This paper describes the results of a field test of the ground-based Airline Based En Route Sequencing and Spacing (ABESS). The main objective of this field test were the conditions of successful long look-ahead trajectory modeling. Longer look-ahead trajectory modeling consists of predicting movement of flights over 60 to 90 min in the future and to determine metering fix crossing times with sufficient quality and little variability. Requirements and feasibility of longer look-ahead trajectories were assessed in a test at the UPS AOC in Louisville Kentucky during April and June of 2009. During this test the trajectory models for sets of UPS flights were compared with their actual flight behavior. However, no operational evaluation with human operators was performed. It was found that though accuracy and stability of trajectories approached levels that appeared usable for spacing flights on some days, accuracy was found to be insufficient on many test days as errors exceeded on average of 1 min on about 50 % of the test days. These results indicate that while the available accuracy of the used trajectory modeler seems sufficient under best case conditions, it seems yet insufficient to support en route ground based spacing for daily use. This paper proposes potential solutions that could address such shortcomings and describes next steps.

Flight deck based indications and alerting to increase runway safety

This paper describes the development of a surface alerting capability based on the use of Automatic Dependent Surveillance-Broadcast (ADS-B) that is projected for use by many classes of aircraft and at a range of airports. The capability is intended to help reduce the risk of runway incursions and collisions. The capability is developed by a working group that is part of RTCA Special Committee (SC) 186. The capability has been termed the Enhanced Traffic Situational Awareness on the Airport Surface with Indications and Alerts (ATSA SURF IA). The capability description is currently in draft status and is projected to be completed by mid 2009. This paper presents the current activity along with a concept description and a description of the main engineering and human factors issues.

En Route Merging and Spacing Preparation concept of operations

This paper describes a concept of operations for improving the merging and spacing operations as aircraft approach and transit into the terminal area that implements the NextGen concept for en route and arrival operations. The En route merging and spacing preparation (EMSP) concept describes the process, procedures, and technical capabilities to modify flight trajectories from multiple airlines to merge at a desired spacing over a specific metering point. EMSP links air navigation service provider (ANSP) with airline operations centers (AOCs) to jointly improve efficiency and capacity constraints. EMSP as it is outlined in this paper will be implemented in three incremental steps with increasing complexity and enhanced capabilities. EMSP is in an early stage of development and is currently under refinement by a development group that consists of members of the federal aviation administration (FAA), the MITRE corporationpsilas center for advanced aviation system development (CAASD), and the national air and space administration (NASA).

Ground and flight deck alternatives for terminal merging, sequencing, and spacing for arrivals

Aircraft approach the terminal area on different arrival paths, merge and ultimately arrive at capacity-constrained runways on the ground. Upon entering the terminal area, air traffic control manually controls the aircraft in order to merge and sequence arrivals on different paths, and establish longitudinal spacing between aircraft. These operations are termed merging, sequencing, and spacing operations. New technologies available in air traffic control facilities and in the flight deck create the possibility of improving on the manual operations used today. Several alternatives are currently in operational trials. Unclear is what alternative will prove to be most desirable for implementation. This paper seeks to enumerate some alternatives, and their characteristics, and establishes a framework for assessment.