Daniel M. Williams

IFR Operations at Non-Towered, Non-Radar Airports: Can we do Better Than One-at-a-Time?

This paper describes a new concept for operations in non-radar terminal airspace around small, nontowered airports. Currently, air traffic operations in instrument meteorological conditions (IMC) at airfields without control towers and radar service are severely constrained by what is known as the one-in/one-out paradigm. Under these conditions only one operation (either arrival or departure) is allowed to occur at a time. Since these operations can take over 15 minutes to complete, capacity at these airports is severely restricted in IMC. The proposed concept is an attempt to break this current paradigm by applying emerging airborne and ground-based technologies to enable simultaneous operations by multiple aircraft in nonradar terminal airspace around small non-towered airports in IMC. The general philosophy underlying this concept of operations is the establishment of a newly defined area surrounding these airports called a Self-Controlled Area (SCA). Aircraft operating within the SCA are required to have a specified minimum level of equipage. Within the SCA, pilots are responsible for separating themselves from other similarly equipped aircraft through the use of new onboard systems and procedures. This concept also takes advantage of newly developed automation at the airport, which provides appropriate sequencing information to the pilots for safe and improved operations. Such operations would enhance the opportunity for point-to-point air taxi or charter operations into smaller airfields that are closer to a traveler s origin and destination. A description of this concept of operations and a simulation environment used for evaluation is provided in this paper.

Flight technical error analysis of the SATS higher volume operations simulation and flight experiments

This paper provides an analysis of flight technical error (FTE) from recent SATS experiments, called the higher volume operations (HVO) simulation and flight experiments, which NASA conducted to determine pilot acceptability of the HVO concept for normal operating conditions. Reported are FTE results from simulation and flight experiment data indicating the SATS HVO concept is viable and acceptable to low-time instrument rated pilots when compared with todays system (Baseline). Described is the comparative FTE analysis of lateral, vertical, and airspeed deviations from the Baseline and SATS HVO experimental flight procedures. Based on FTE analysis, all evaluation subjects, low-time instrument-rated pilots, flew the HVO procedures safely and proficiently in comparison to todays system (Baseline). In all cases, the results of the flight experiment validated the results of the simulation experiment and confirm the utility of the simulation platform for comparative human in the loop (HITL) studies of SATS HVO and Baseline operations.

Small Aircraft Transportation System, Higher Volume Operations Concept and Research Summary

Described is the research process that NASA researchers used to validate the Small Aircraft Transportation System (SATS) Higher Volume Operations (HVO) concept. The four phase building-block validation and verification process included multiple elements ranging from formal analysis of HVO procedures to flight test, to full-system architecture prototype that was successfully shown to the public at the June 2005 SATS Technical Demonstration in Danville, VA. Presented are significant results of each of the four research phases that extend early results presented at ICAS 2004. HVO study results have been incorporated into the development of the Next Generation Air Transportation System (NGATS) vision and offer a validated concept to provide a significant portion of the 3X capacity improvement sought after in the United States National Airspace System (NAS).The ability to conduct concurrent, multiple aircraft operations in poor weather at virtually any airport offers an important opportunity for a significant increase in the rate of flight operations, a major improvement in passenger convenience, and the potential to foster growth of operations at small airports. The Small Aircraft Transportation System (SATS), Higher Volume Operations (HVO) concept is designed to increase capacity at the 3400 nonradar, non-towered airports in the United States where operations are currently restricted to “one-in/one-out” procedural separation during low visibility or ceilings. The concept’s key feature is that pilots maintain their own separation from other aircraft using air-to-air datalink and on-board software within the Self-Controlled Area (SCA), an area of flight operations established during poor visibility and low ceilings around an airport without Air Traffic Control (ATC) services. While pilots self-separate within the SCA, an Airport Management Module (AMM) located at the airport assigns arriving pilots their sequence based on aircraft performance, position, winds, missed approach requirements, and ATC intent. The HVO design uses distributed decision-making, safe procedures, attempts to minimize pilot and controller workload, and integrates with today’s ATC environment. This paper summarizes the HVO concept and procedures, presents a summary of the research conducted and results, and outlines areas where future HVO research is required.

Conflict Prevention and Separation Assurance in Small Aircraft Transportation Systems

A multilayer approach to the prevention of conflicts due to the loss of aircraft-to-aircraft separation that relies on procedures and onboard automation was implemented as part of the Small Aircraft Transportation Systems Higher-Volume-Operations concept. The multilayer system gives pilots support and guidance during the execution of normal operations and advance warning for procedure deviations or off-nominal operations. This paper describes the major concept elements of this multilayer approach to separation assurance and conflict prevention and provides the rationale for its design. All the algorithms and functionality described in this paper were implemented in an aircraft simulation in the Air Traffic Operations Laboratory at NASA Langley Research Center and on the NASA Cirrus SR22 research aircraft.

Conflict Prevention and Separation Assurance Method in the Small Aircraft Transportation System

A multilayer approach to the prevention of conflicts due to the loss of aircraft -to -aircraft separation which relies on procedures and on -board automation was implemented as part of the SATS HVO Concept of Operations. The multilayer system gives pilots support and guidance during the execution of normal operations and advance warning for procedure deviations or off -nominal operations. This paper describes the major concept elements of this multilayer approach to separation assurance and conflict prevention and provides the rationale for its design. All the algorithms and functionality described in this paper have been implemented in an aircraft simulation in the NASA Langley Research Center’s Air Traffic Operation Lab and on the NASA Cirrus SR22 research aircraft.

Considerations in the Integration of Small Aircraft Transportation System Higher Volume Operations (SATSHVO) in the National Airspace System (NAS)

The Small Aircraft Transportation System Higher Volume Operations (SATS HVO) concept holds the promise for increased efficiency and throughput at many of the nations under-used airports. This concept allows for concurrent operations at uncontrolled airports that under today s procedures are restricted to one arrival or one departure operation at a time, when current-day IFR separation standards are applied. To allow for concurrent operations, SATS HVO proposes several fundamental changes to todays system. These changes include: creation of dedicated airspace, development of new procedures and communications (phraseologies), and assignment of roles and responsibilities for pilots and controllers, among others. These changes would affect operations on the airborne side (pilot) as well as the groundside (controller and air traffic flow process). The focus of this paper is to discuss some of the issues and potential problems that have been considered in the development of the SATS HVO concept, in particular from the ground side perspective. Reasonable solutions to the issues raised here have been proposed by the SATS HVO team, and are discussed in this paper.

CONCEPT VALIDATION EXPERIMENT FOR SMALL AIRCRAFT TRANSPORTATION SYSTEM HIGHER-VOLUME OPERATIONS

A human-in-the-loop simulation experiment was conducted at the NASA Langley Research Centers Air Traffic Operations Laboratory in an effort to comprehensively validate tools and procedures intended to enable the small aircraft transportation system higher-volume-operations concept of operations. These procedures were developed with the goal of increasing the rate of operations at nontowered, nonradar airports in near all-weather conditions. A key element of the new design is the establishment of a volume of airspace around designated airports at which pilots accept responsibility for self-separation. Flights operating at these airports are given approach-sequencing information computed by a ground-based automated system. The validation experiment was conducted to determine if a pilot could safely and proficiently fly an airplane while performing the newly developed procedures. Comparative measures of flight path error, perceived workload, and situation awareness were obtained for two types of simulated scenarios. Baseline scenarios were representative of todays system using procedure separation, in which air traffic control grants one approach or departure clearance at a time. Test scenarios represented the newly developed approach and departure procedures. Results from the experiment indicate that low-time pilots were able to fly the test procedures in a simulation environment and maintain self-separation as safely and proficiently as flying todays procedures.

The Small Aircraft Transportation System, Higher Volume Operations Off -Nominal Operations

*† ‡ § ** †† The ability to conduct concurrent, multiple aircraft operations in poor weather, at virtually any airport, offers an important opportunity for a significant increase in the rate of flight operations, a major improvement in passenger convenience, and the potential to foster growth of charter operations at small airports. The Small Aircraft Transportation System (SATS) , Higher Volume Operations (HVO) concept is designed to increase traffic flow at any of the 3400 non -radar, non -towered airports in the United States where operations are currently restricted to “one -in/one -out” procedural separation during Instrument Meteorological Conditions (IMC). The concept’s key feature is pilots maintain their own separation from other aircraft using procedures , aircraft flight data sent via air -to -air datalink, cockpit displays, and on -board software. This is done within the Self -Controlled Area (SCA), an area of flight operations established during poor visibility or low ceilings around an airport without Air Traffic Control (ATC) services. The research described in this paper expands the HVO concept to include most off -nominal situations that could be expected to occur in a future SATS environment. The situations were categorized into routine off -nominal ope rations, procedural deviations, equipment malfunctions, and aircraft emergencies. The combination of normal and off -nominal HVO procedures provides evidence for an operational concept that is safe, requires little ground infrastructure, and enables concur rent flight operations in poor weather.

SATS HVO Concept Validation Experiment

A human -in -the -loop simulation experiment was conducted at the NASA Langley Research Centers (LaRC) Air Traffic Operations Lab (ATOL) in an effort to comprehensively validate tools and procedures intended to enable the Small Aircraft Transportation System, Higher Volume Operations (SATS HVO) concept of operations. The SATS HVO pr ocedures were developed to increase the rate of operations at non -towered, non -radar airports in near all -weather conditions. A key element of the design is the establishment of a volume of airspace around designated airports where pilots accept responsibi lity for self -separation. Flights operating at these airports, are given approach sequencing information computed by a ground based automated system. The SATS HVO validation experiment was conducted in the ATOL during the spring of 2004 in order to determi ne if a pilot can safely and proficiently fly an airplane while performing SATS HVO procedures. Comparative measures of flight path error, perceived workload and situation awareness were obtained for two types of scenarios. Baseline scenarios were represen tative of todays system utilizing procedure separation, where air traffic control grants one approach or departure clearance at a time. SATS HVO scenarios represented approaches and departure procedures as described in the SATS HVO concept of operations. Results from the experiment indicate that low time pilots were able to fly SATS HVO procedures and maintain self -separation as safely and proficiently as flying todays procedures.

Small Aircraft Transportation System Higher Volume Operations Flight Experiment

This paper summarizes findings from the Small Aircraft Transportation System Higher Volume Operations Flight Experiment. The higher volume operations concept improves efficiency at nontowered, nonradar airports in instrument meteorological conditions. The success of the higher volume operations concept is based on pilot acceptability as determined through objective and subjective assessments when compared with the procedural control operations in use today at nontowered, nonradar-controlled airfields in instrument meteorological conditions. Flight experiment data indicate that the concept is viable. The experiment, flown on a general aviation aircraft, used a subset of the Higher Volume Operations Simulation Experiment scenarios and evaluation pilots to validate the simulation experiment results. Results reveal that all 12 low-time instrument-rated pilots preferred Small Aircraft Transportation System Higher Volume Operations when compared with current procedural separation operations. These pilots also flew the higher volume operations procedures safely and proficiently without additional workload in comparison to todays system. Detailed results of pilot flight technical error and their subjective assessments of workload and situation awareness are presented.