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Airborne Technology for Advanced Vehicle Operations in the Next Generation ATS.

Rosa M. N. Weber1 Honeywell International, Golden valley, MN 55422

In order to meet NextGen safety, environmental and capacity goals, details for the NextGen Air Transportation System are being developed in concert with the design of several advanced airborne vehicles. This paper describes the unique performance characteristics and missions selected for five advanced vehicles and summarizes the safety challenges that these advanced vehicles will face as they are introduced into the NextGen Air Transportation System circa 2025. This paper will focus on the onboard avionics system functionality that is needed to mitigate the safety hazards when these advanced vehicles are utilized on capacity-enhancing missions across our future NextGen Air Transportation System.

I. Introduction The Next Generation Air Transportation System (NextGen) concept of operations was developed to address the

Air Traffic Management (ATM) challenges envisioned for our future airspace. Upgrades to infrastructure, ground-based and airborne system, changing roles and responsibilities of pilots and controllers, greater flexibility in user preferred routing, as well as modified flight procedures are just a few of the changes that will be undertaken in our National Airspace System (NAS) to address growing air traffic demands and meet stringent safety, noise and emissions standards. The NextGen concept of operations identifies the key issues, trades and the major concepts of our future ATM system. However, the details of how this system will operate will be defined by additional studies of the complex interactions between our national airspace and the vehicles that operate in that airspace. For example, in recent years we have observed an increase in on-demand air taxi operations, greater usage of very small and very light jets, a strong desire for a wider use of unmanned aircraft systems and greater utilization of regional and uncontrolled airports to offload traffic from nearby high density airports. These changes are early indicators that the dynamics of our NAS will change as new vehicle types, both crewed and uncrewed, enter our airspace in increasing numbers. Studies conducted by the JPDO’s System Modeling and Analysis Division (SMAD) indicate that some of the JPDO future environmental goals cannot be realized without the introduction of new engine and airframe technologies[1]. The NextGen capacity goals will also be difficult to achieve without advances in Guidance, Navigation, Communication and Surveillance technology that will be part of the avionics found on new vehicles introduced in the NAS circa 2020 and beyond.

In an effort to identify technology standardization, deployment and investments strategies, as well as refine the NextGen concept of operations, multiple FAA/JPDO and NASA-sponsored programs have recently been introduced. NASA initiated the “Integration of Advanced Concepts and Vehicles into the Next Generation Air Transportation System” program to understand the impact that new vehicles will have on the envisioned NextGen Air Transportation System (ATS). On the NASA advanced vehicles program, two parallel teams have been tasked to identify the tradeoffs between new vehicles performance capabilities and the envisioned ATM system, and address the safety, environmental, and capacity challenges of the future Air Traffic Management (ATM) system. Both teams have been assigned five different advanced vehicles to analyze. These vehicles were chosen for their widely varying performance characteristics. Vehicles include a Cruise Efficient Short Take-Off and Landing (CESTOL) large Subsonic Transport aircraft, Very Light Jets (VLJ), Unmanned Aircraft Systems (UAS), Large Civil Tilt Rotorcraft (LCTR), and Super Sonic aircraft (SST). This paper will describe the five vehicle types shown in Figure 1and Figure 2, which are a subset of the new vehicles currently under development.

1 Principal Research Scientist, Communication, Navigation & Surveillance Systems, 1985 Douglas Drive, Golden Valley, MN 55422, member.

9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) <br>and <br>Air21 - 23 September 2009, Hilton Head, South Carolina

AIAA 2009-7071

Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Governmental purposes.All other rights are reserved by the copyright owner.

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Figure 1  LCTR, UAS and CESTOL vehicles 

Figure 2 VLJ and SST vehicles 

UAS and VLJs are already in production today. However, UAS today are limited in their use within the National Airspace System (NAS) due to the lack of mature sense-and-avoid technology. VLJs are already in use by both private operators as well as air taxi services. The remaining three advanced vehicle types—LCTRs, SSTs, and CESTOLs—are currently under development by industry. The time period for this study is 2025-2040, during which many of these vehicles should be in routine operational use, and during which NextGen is targeted to be fully operational. In order to push the feasibility of the NextGen concept of operations, each of these vehicles was given a unique mission in line with the modified airspace and airport usage needed to handle increased traffic demands. This paper discusses one of the research questions that our team was asked to address: What are the safety challenges that these new vehicles will encounter when operating in our future ATS and how can these safety challenges be mitigated via modifications to the airspace and improvements in aircraft avionics? This paper will focus on the avionics that can aid in the mitigation of these safety challenges. My colleagues have described other aspects of our research in [2-10].

This paper will briefly describe the unique performance characteristics and missions selected for each of the five advanced vehicles, summarize the hazards that these vehicles may be susceptible to, and thereafter focus on the airborne technologies that are essential for the unique performance capabilities and missions slated for these advanced vehicles. For instance, the CESTOL aircraft has the unique capability to use terrain-challenged airports by executing spiral approach and departure maneuvers. Safe CESTOL operations in the future NAS will require the inclusion of airborne technology that ensures the safe execution of this specialized maneuver. This paper will describe the technology on-board the CESTOL aircraft that are anticipated to be available in the timeframe that this advanced vehicle will be introduced into our NAS.

The remainder of this paper is organized as follows: section II will describe previous work that served as a starting point for defining avionics technology readiness timelines. The performance characteristics and missions planned for the advanced vehicles are described in section III and IV respectively. Section V discusses the timeframe when each of the advanced vehicles will enter our NAS and the NextGen ATM environment assumptions for this timeframe. Section VI summarizes the unique safety challenges and hazards that must be mitigated for each vehicle. Section VII details the airborne technology required to ensure efficient and safe operations of the advanced vehicles in the NextGen environment. A summary and conclusion are provided in section VIII. The glossary and references sections appear at the end of this paper.

II. Previous work Studies of new vehicle technologies have been ongoing for many years. There have been numerous studies of CESTOL technologies in the last decade including a study of the Short Take Off and Landing (STOL) technology on a hypothetical single-runway airport [11]. Supersonic transports were analyzed during NASA’s High Speed research program in the mid 1990’s and are the focus of the supersonic project [12], as part of NASA’s on-going Fundamental Supersonic Program. NASA has actively studied civil tilt rotor operations over the last two decades. Significant research and standardization efforts have been conducted on technology necessary to integrate UAS into the National Airspace System (NAS) as well as best practices for UAS use prior to the availability of the sense-and-avoid capability [13]. As VLJs are already in commercial use today, several studies have focused on the impact of

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VLJs in our commercial airspace [14]. The analysis of the impact on the NextGen ATS by advanced vehicle types is in its infancy; before NASA’s “Integration of Advanced Concepts and Vehicles into the Next Generation Air Transportation System” program, this field of study was largely unexplored.

A significant amount of work on the identification of essential airborne and ground based technologies to realize the anticipated NextGen ATS has been conducted by both government agencies and industry. The JPDO Aircraft Working Group has published their NextGen Avionics Report which translates many of the proposed NextGen improvements into aircraft capabilities and functions. This roadmap has mapped and described the airborne technology in development, flight tested, or in operation from today through the NextGen midterm timeframe (i.e., through 2018). Future versions of this roadmap will also address far-term (2019+) avionics technologies. The FAA NAS Enterprise Architecture Infrastructure working group published two sets of NAS Enterprise Architecture Infrastructure roadmaps: service roadmaps that identify the evolution of air traffic services and drive the associated technology requirements, and infrastructure roadmaps that identify dependencies, e.g., between technologies and their scheduled introduction. On the NASA Advanced Concepts and Vehicles program we have extended these aircraft-specific roadmaps with the technologies envisioned by avionics manufacturers, OEM’s and aviation researchers to enable the safe execution of advanced vehicle operations in our future NextGen ATS.

III. Vehicle Performance characteristics Researchers at the Georgia Institute of Technology have designed the vehicle performance characteristics of the

five advanced vehicles described in this paper [3]. The CESTOL aircraft has been designed as a replacement for 100-150 passenger commercial jets. It has been designed to operate much like a Boeing 737-class aircraft, yet has been extended with airframe and engine performance characteristics that enable it to perform STOL operations. This advanced vehicle is slated to replace existing aircraft around the 2020 timeframe. For our VLJ advanced vehicle, engine, avionics, and airframe improvements have been made to the Eclipse 500 to reduce cost, noise, and emissions, and provide this advanced vehicle with the ability to execute steeper take offs and approaches (using a 5.5 degree final approach glide slope) to help reduce the field length requirement.

Both the CESTOL subsonic transport aircraft and Very Light Jet have been designed to perform spiral descent and approach maneuvers at 30-degree bank angles and 5.5 degrees glide slope. They can operate at slow approach speeds and steep approach angles to limit noise for use in noise sensitive areas. Spiral approaches with low noise allow these vehicles to utilize unused airspace above an airport and thus fly into airspace-challenged airports in high-density terminal areas. Figure 3 Spiral Approach onto RW18 at Newark Liberty Airport. Today, steep approaches are already mandatory at London City Airport for noise abatement purposes and spiral approaches are in use at several airports in the Asia-Pacific region including a terrain challenged Qantas approach flown into Queenstown, New Zealand. The effectiveness and need for spiral approaches can already been seen in airports such as the Palm Springs International Airport (PSP) in California where two RNP approaches, although not quite spirals, include a 270 degree turn, needed due to terrain challenges.

Today, no commercial operations occur on short runways at high density airports. STOL operations with the CESTOL and VLJ aircraft can provide throughput benefits for our future ATS. At sea-level, the 100 passenger CESTOL is able to land on runways as short as 3188 ft and take off on runways as short as 3020 ft. The four-passenger VLJ only requires a runway length of 2,345 ft for takeoff and 2,250 ft for landing. The reduced landing field length requirements can significantly increase capacity at dense metroplexes like NY’s LGA where two aircraft can simultaneously takeoff and land on 7000 feet runways. Another interesting use of these advanced aircraft is their ability to operate on intersecting runways such as runways at LGA and SFI.

The performance characteristics of our UA will be based on the Cessna caravan super cargomaster evolved to 2025. The UA will have a maximum cruise speed of 175 ktas, with a certified ceiling of 25,000 ft and an improved payload-range of 1,080 nautical miles, or 2,000 kilometers. However, due to its assigned mission, as described in section IV, the UAS nominal range will be between 30 and 150 nm. The cruise altitude is expected to max out at 11,000 feet (FL 110) because of the short flight distances. The unmanned Cessna Caravan’s performance characteristics allow it to function as a MALE unmanned aircraft. However, on the short haul cargo flights, it could operate as a tactical UA. (Altitude up to FL180, range about 160nm). Larger cargo UA can perform steeper descents at night for noise reduction purposes. For descent, the terminal approach is assumed to be at 5.5 degrees although it can be flown at 3 degrees for compatibility. We do not assume any unique climb profiles for our cargo UA. Our cargo UA is not substantially different from current manned aircraft, however, the unmanned aircraft can perform maneuvers that would upset passengers or crew members. It will be able to execute relatively steep descents and can fly, briefly, in negative G flight. Our cargo UA can loiter longer than piloted aircraft (e.g. if

weather prevented immediate landing) and as a fully autonomous, auto-piloted aircraft, our UA is expected to fly more precise trajectories than a manually piloted flight.

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Steep ApproachDescent slope: 5.5 deg

35ft height obstacle

Spiral Descent• Turn radius 1.5 nm• Load factor <= 1.15, variable• Bank angle <= 30 deg, variable • Descent slope 5.5 degrees

FlareTouch Down

10k ft

1,000 ft

 

Figure 3 Spiral Approach onto RW18 at Newark Liberty Airport

The Large Civil Tilt Rotor has been designed to replace regional airliners over medium ranges. This advanced vehicle will have a two pilot crew and is designed to carry 90 passengers for 1,000 nautical miles with a cruise speed of 300 knots at 28,000-ft altitude. The LCTR can perform 45-degree banked turns at 80 knots. This Vertical Take Off and Landing (VTOL) vehicle, as well as our STOL vehicles, can exploit reliever airports near congested airports to offload traffic and increase capacity with minor affect on overall delays.

The SST is a new supersonic commercial transport that is slated for entry into our NAS around 2025. The SST has been designed as part of a new class of civil transport which is able to provide a low-boom signature and reduce environmental impacts when compared to its commercial predecessor, the Concorde. The SST aircraft will be a 100 passenger intercontinental and/or transcontinental jet cruising at Mach 1.6. The SST is expected to operate as a traditional subsonic transport in the terminal environment, while reaching supersonic speeds during cruise. The SST takeoff field length is 10,000 feet with a landing field length requirement of 7,154 ft. This advanced vehicle can reach destinations up to 4,000 nautical miles and is capable of operating at altitudes of up to 53,000 feet in airspace customarily used by business jets. With a cruising altitude between FL450 and FL530, SSTs will be operating above most of the weather. However, SSTs will be subjected to weather at the lower altitudes during takeoff and landing operations.

IV. Advanced Vehicle missions As we studied the various performance characteristics of our advanced vehicles and the critical throughput needs

of our NAS in the 2025+ timeframe, we selected the following missions for our five advanced vehicles: • CESTOL Utilizing reliever airports in large metroplex areas • VLJ Air taxi operations between uncongested city pairs • UAS Overnight freight-forwarding operations from “spokes” to small rural areas • LCTR Short haul shuttle flights between reliever airports in major metropolitan areas. • SST Long-haul transport serving market need for fast travel

The CESTOL aircraft will operate in the city-to-city market, flying up to 100 passengers between highly congested city pairs such as SAN-LAX, or city airports in the Northeast, located within a 600 nm range. This advanced vehicle with be able to increase high density route capacity by operating on underutilized runways at hubs and reliever airports in large metroplex areas.

The mission for our four-passenger VLJ is on-demand, point-to- point air taxi service to non-hub airports. VLJs will provide business and upscale leisure travelers with a convenient point-to-point substitute for traditional hub airline services. None of these short-haul flights will originate or depart at any of our top 35 most congested

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airports; instead, they utilize city pairs that are relatively uncongested. The VLJ has been designed to take advantage of underutilized regional airports and underutilized runways at hubs. A significant number of operations will be into primarily GA and non-towered airports. These non-congested, underused airports may lack the runway, taxiway, or terminal facilities to support larger aircraft.

The freight-forwarding mission for our UAS is a civilian mission with potentially large impacts on NextGen. Similar to Fed Ex routes flown today, cargo is routed from hubs at major airports to spoke airports nearby the final package destinations. At spoke airports, freight forwarding of ~ 2000 lbs of cargo over 30 to 150nm distances can benefit from the use of unmanned aircraft systems. The business decision to forward the freight onward to its final destination by truck or by small aircraft is based on cost. If UAS technology is used to convert today’s manned freight forwarding aircraft into fully autonomous unmanned aircraft, the cost of operating that aircraft may decrease and thus small unmanned aircraft system use for freight forwarding operations is expected to increase. Our cargo UAS will operate at underutilized medium and small airports across our NAS.

The mission analyzed for our LCTR was the operation of shuttle services between heavily-travelled city pairs (e.g., LAX to SFI) in order to offload traffic at congested airports. The 90 passenger LCTR can utilize vertiports at large metroplex airports to free up arrival and departure slots on the main runways, operate at reliever airports near metropolitan areas, or fly passengers into feeder airports. The LCTR has been designed for short-haul (< 500 nm) operations. The LCTR shuttle flights occur between heavily travelled airports with sophisticated ground infrastructure that support advanced NextGen ATS operations.

The mission for the 100 passenger SST is to offer high-end service to elite passengers and provide faster hub to hub connections on long haul international and domestic routes. On a standard day, this aircraft will be limited to take off operations at airports with a 10,000 ft runway and landing operations at airports with a runway of at least 7,154 feet in length. These airports are also heavily travelled airports with sophisticated ground infrastructures and full ATC services.

Our advanced vehicles meet several critical needs within the NextGen ATM environment: access to terrain-restricted airports, increased throughput at high density airports and utilization of underutilized runways and uncongested airspace and airports.

V. Future Airspace To determine the airborne technologies that may be available to ensure safe advanced vehicle operations in the future NextGen ATM environment we need to consider several other aspects besides the unique performance characteristic and assigned missions for our advanced vehicles: 1. In what timeframe will the advanced vehicles enter our NAS? 2. What are the NextGen ATM environment assumptions for this timeframe? 3. What are the unique, vehicle-specific safety challenges and hazards that must be mitigated?

Timeframe VLJs already exist today and are in active use for air taxi operations. The CESTOL subsonic transport aircraft is

slated for an Initial Operating Capability (IOC) of 2021. The LCTR has an IOC date of 2018 and we assume an IOC of 2025 for the SST and the fully autonomous cargo UAS.

NextGen ATS assumptions for 2025 The airspace and infrastructure assumptions for the NextGen ATM environment of 2025 impact vehicle

operations within the mission we have identified. Key enablers for the NextGen ATS include Performance Based Navigation, Trajectory-Based Operations (TBO), a shift from tactical to strategic Separation Management, Net-centric Operations and digital data communication (Data Comm). Each advanced vehicle will be equipped with the avionics system functionality needed to gain the benefits granted to equipped aircraft operating in the NextGen ATS. A. Performance Based Navigation

The NextGen ATS will be based on 4D RNAV flight path management in core areas and RNP RNAV in non-core areas. RNP and flexible, accurate RNAV flight paths will be used for terminal area, approach and missed approach procedures. RNAV will be used to address numerous operational conditions such as parallel runways operations, adjacent runways, crossing runways, nearby runways at adjacent airports, and terrain or noise limited runway operations. This will include emission and noise reducing operations such as continuous descent arrivals (or profile descents). In the ATM system for 2025 and beyond, we will see the transition from today’s flight plans

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to RNP RNAV trajectory-based flight plans negotiated with ATC. New procedures that take advantage of the new vehicle performance and avionics capabilities will be developed to enhance traffic integration of the advanced vehicle into the terminal environment. Optimal profile descents (i.e., continuous descents approaches) will help alleviate fuel costs and enhance the advanced vehicle business viability. B. Trajectory-based Operations (TBO)

4-D navigation and control will allow properly equipped aircraft to file 4-D flight plans and integrate seamlessly into the NAS. Aircraft that fly in trajectory-based airspace will navigate along 3D or 4D (position, altitude and time) specified trajectory, within a time tolerance along a series of trajectory waypoints. Negotiation of user-preferred trajectories will optimize fleet operations, minimize fuel usage and emissions, and increase throughput at the nation’s busiest airports. C. Separation Management

Alternate separation methods will be in place with separation responsibility delegated to the aircraft for specific situations. Merging and spacing operations, In Trail Spacing and passing, and separation flight path management will be normal operating procedures for aircraft flying in the NAS. ADS-B OUT for fleet management, procedure compliance, and surveillance services as well as ADS-B IN for separation, spacing, merging, surface operations will be in place. Minimum separation standards may be reduced to increase system capacity. Airborne separation and delegation procedures and technologies and adherence to 4D trajectories will provide the means by which our advanced vehicles can safely separate themselves from other aircraft. D. Net-Centric Operations and the Shared System Wide Information Management System (SWIM)

Our advanced vehicles will be consumers and providers of data stored in SWIM. SWIM will be the centralized system for trajectory management, weather data, airspace restrictions, weather hazards and information, and real-time obstacle data. (e.g., balloons, sky divers, etc). SWIM facilitates the integration of the advanced vehicles into the NAS by sharing the intended trajectory and current position of the advanced vehicle with other airspace users. Wind, temperature or other data gathered during a vehicles’ ascent and descent can be shared with other airspace users via SWIM. Convective weather forecasts and reports stored in SWIM can be accessed by the aircraft or Airline Operating Center (AOC) for planning and rerouting purposes. SWIM will facilitate flight operations near military, restricted, or other hazardous airspace by providing aircraft with dynamic updates on the number and size of restricted, sensitive (e.g., noise sensitive areas) or “no fly” zones sensitive locations. E. Data Communication

Data communications in 2025 will be primary conducted via datalink with voice communication largely limited to special advisories and emergency situations. Data communication will transition from a voice based ATC communication system to a data driven system integrated with automation in support of NextGen. Communications between the flight crew of our advanced vehicles and ATC will be dominated by electronic data exchanges which require operator acknowledgement and approval prior to execution. Besides shared data exchange with SWIM, the on-board communications technology will be utilized for flight trajectory negotiations, data exchange for distributed decision making and digital audio/video transmissions.

VI. Safety Hazards Now that we understand the avionics system functionalities that will be onboard the advanced vehicles to fully

participate in the NextGen ATS, we need to discuss the avionics extensions required to support the unique vehicle operations of our advanced vehicles and avionics functionality needed to mitigate the safety hazards that arise is the execution of these unique maneuvers on the missions conducted by our advanced vehicles. No vehicle will be immune to the hazards caused by wake vortices, convective weather, or low altitude operations. Additional hazards that each advanced vehicle could potentially be exposed to include loss of situation awareness, loss of flight path performance and unstablized approaches. The hazards associated with operations at low infrastructure airports or high density metroplexes depended on the missions that the vehicles were chosen to fly. The vehicle-specific safety concerns developed on this contract are described in detail in [2, 15, 16, 17, 18, 19]. A subset of the relevant hazardous conditions is listed in Table 1 below.

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Table 1  Advanced vehicles and the hazards they are especially susceptible to 

Hazardous Conditions CESTOL VLJ UAS LCTR SST Unstablized Approach Loss of Flight Path Performance Convective Weather Loss of Separation Minima (Airborne and surface)

• Low infrastructure or uncontrolled airports • Unpiloted vehicle

• High density airports Loss of command or control Wake turbulence Loss of Situation Awareness (Manned AC)

• Cockpit windscreen view restrictions • Pilot workload

Loss of Situation Awareness (Unmanned AC) • Loss of situation awareness datalink

A. Unstabilized Approach

Unstable approaches significantly increase the risk of runway excursions, runway undershoots or overshoots or tail strikes. An unstablized approach can also lead to impact with ground objects, terrain or airspace infringement resulting in possible damage to the aircraft or injury to passengers or crew. Runways equipped with ILS precision approach instrumentation and wind anemometers add ‘Precision’ to the Non Precision Approach. Non-precision approaches into low infrastructure airports increase the likelihood of a safety incident due to unstablized approach. B. Loss of flight path / navigation performance

Loss of flight path performance during low-light-level or instrument condition could potentially result in a collision hazard with other aircraft on adjacent flight paths if the advanced vehicle deviates from its assigned flight path. There is an increased risk of airspace violations and mid-air collisions when executing low RNP (e.g., 0.1) or spiral approaches in close proximity to other aircraft or terrain at a high density airport. C. Convective Weather

Severe weather is a factor in about one-third of all aircraft accidents, turbulence is the leading cause of injury to passengers and crew members, and 40 percent of flight delays are caused by bad weather. Severe weather not only increases the probability of icing, it also impacts the flight safety of aircraft by reduction in visibility, increases in wind, windshear, turbulence and the hazards due to thunderstorms (gusts, downbursts…) or thunderstorm avoidance (e.g., rerouting). Undetected encounters with adverse environmental conditions can lead to aircraft operating outside their performance envelope resulting in possible near mid-air, or mid-air collision with other aircraft, terrain or objects. All aircraft are susceptible to convective weather. However, aircraft operating at low altitudes, at slow approach speeds, high bank angles or without the benefits of ATC services will be especially susceptible to severe weather.

D. Loss of separation minima

Failure of the pilot to maintain spacing and adhere to separation minima in high density terminal airspace could result in overtaking slower aircraft or be overtaken by faster aircraft which could result in a near mid-air, or mid-air collision. For instance, failure of the SST to transition between supersonic and subsonic speeds during the approach transition could result in the aircraft exceeding the separation minimums if the speed is too fast which could cause conflict with other aircraft. Lack of infrastructure support on the ground at regional, rural, or non-towered airports contribute to separation hazards for advanced vehicle flight operations. Non-precision approaches, the absence of surface radar, weather data, and possibly ATC services, are key contributors to potentially higher incidents of these accidents.

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E. Loss of command or control Total loss, degraded performance, or unauthorized access to the command and control data link might cause the

Unmanned Aircraft (UA) to make an unpredictable maneuver with the remote pilot unable to control the UA, resulting in possible near mid-air or mid-air collision with other aircraft, terrain or objects.

F. Wake Turbulence

Failure to ensure appropriate separation behind aircraft that generate significant wake turbulence could result in possible loss of control. This might result in possible near mid-air, or mid-collision with other aircraft, terrain or objects. This could ultimately result in loss of life or damage to property on the surface. Aircraft taking off and landings at low speeds and high angle of attack, or in STOL or VTOL mode must be very cognitive of the wake vortices they generate as well as the vortices generated by the aircraft surrounding them, especially when operating at high density airports or on parallel or crossing runways. G. Loss of Situation Awareness – Manned aircraft

Human factors issues (increased pilot reliance on automation, situation awareness) caused by higher glideslope, steeper sink rate, earlier go-around decision points, spiral operations and recovery during emergency situations must be mitigated for our advanced vehicles. Pilots succumbing to information overload in the terminal environment increase their chances of losing positional awareness and could increase the possibility of becoming involved in a near mid-air collisions or contact with other objects or terrain.

Collision hazards also exist due to the steep, rapid climb-out capability of the VLJ and CESTOL aircraft on departure, or steep descent on approach when wing configuration or cockpit windscreen view restrictions could result in a near mid-air or mid-air collision. Windscreen view restrictions also exist for the SST. A fixed wing SST will require this advanced vehicle to land at a high angle of attack (hence less visibility) to create a higher lift since the wing is designed for subsonic cruise and is not as efficient in subsonic flights. For a swing-wing configuration, the SST design requires the addition of a boom at the nose of the aircraft which also reduces the out-of-the-window visibility for the SST flight crew. LCTR VTOL operations restrict the pilot’s visibility of the airspace or terrain directly above or below this advanced vehicle.

H. Loss of Situation Awareness – Unmanned aircraft

The loss or degradation of the situation awareness datalink between the unmanned aircraft and the UAS ground pilot will result in the loss of situation awareness by the ground pilot. For a fully autonomous UA, near mid-air or mid-air collision with other aircraft, terrain or objects can result due to loss of the situation awareness datalink, especially when combined with unpredictable UA maneuvers or non-nominal situations.

VII. Airborne Technology for safe Vehicle Operations On-board avionics will be part of the solution to mitigate the hazards associated with advanced vehicle

operations. Airspace procedures, pilot and controller training and ground-based technology will contribute other essential parts of the hazard mitigation strategy. The avionics critical to safe advanced vehicle operations must aid the pilot to maintain situation awareness during spiral operations, avoid terrain and airspace infringements, facilitate surface operations during STOL operations, avoid wake vortex and hazardous weather conditions and ensure highly accurate climb and descent profiles during simultaneous approach and departure operations.

Our advanced vehicle take off and landing capabilities, autonomous or supersonic flight operations and new operating procedures at busiest airports will stress various concepts developed on NextGen, including controlled time of arrival and delegated separation. For instance, spiral or steep approaches and departures will require self-separation operations in the terminal area. Existing avionics equipment will need to be augmented and additional functionality must be installed on our advanced vehicles to enable their unique performance capabilities in the NextGen ATS. For example, the FMS will need to be enhanced in several areas: • High integrity VNAV • Grid based weather modeling • Time Of Arrival Control (TOAC) at multiple waypoints in climb / cruise / descent flight phases • Datalinked 4D route clearance • Dynamic flight planning & negotiations • Runway database extensions to support STOL operations • Reduced noise and emissions cost index flights, and

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• Integration with Airborne Separation Assurance Surveillance (ASAS) functionality.  

Current Traffic Collision Avoidance System (TCAS) functionality will have to be reconfigured as it is insufficient to handle closure rates of supersonic flights or spiral approaches in the proximity of standard approaches. These avionics upgrades, amongst many others, will be necessary to handle advanced vehicle operations in our future enroute and terminal environment.

Advanced Vehicles Avionics Roadmap Similar to the NextGen avionics roadmap developed by the JPDO Aircraft Working Group, we have mapped the

safety hazards identified for our advanced vehicles and the avionics that can be used to mitigate these hazards against the operational capabilities defined in the NextGen Implementation Plan. The NextGen Implementation Plan has categorized the aircrafts-specific operational capabilities such as weather avoidance, or 3D RNP arrival and departure operations, in terms of the following categories, or capability groups: • Safety Enhancements • Trajectory-Based Operations – Published Routes/Procedures • Trajectory-Based Operations – Negotiated Routes • Aircraft Separation • Low-visibility Approach/Departure/Taxi • ATM Efficiencies

The advanced vehicle avionics roadmap shown below includes the estimated timeframe for the availability of the onboard technology. In line with the timeframes used in the NextGen implementation plan and the Aircraft roadmap, near term capabilities are expected to be available by the end of 2011, mid-term capabilities are expected between 2012 and 2018, while far-term capabilities are from 2019 to 2025. The avionics functionality and associated avionics systems summarized in Table 2 are described in detail in the vehicle-specific avionics roadmaps [20, 21, 22, 23, 24] developed on this contract. Table 2  Advanced Vehicles Avionics Roadmap 

Capability Group/Category Operational Capability Hazardous Situation Avionics

Functionality Time frame

Safety enhancement / hazard avoidance & mitigation

Enhanced Low Altitude Operations

Impact with terrain due to unstable approach or pilot loss of situation awareness

E-GPWS / TAWS enhancements (e.g., RAAS, Stable Approach Monitor, Landing advisories) Higher integrity / resolution terrain databases to reduce CFIT. E-GPWS integrated with 3D RNP.2 ESVS

Near term

Weather Avoidance Severe weather, icing, windshear, etc.

Weather radar integrated with E-GPWS. E-GPWS / TAWS

Mid term

2 Mid term for LCTR

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enhancements: Assisted Recovery Systems (ARS) FIS-B, moving map, SWIM weather forecast uplinks

Aircraft datalinks (e.g., DataComm, ATN/CLNP, IP protocols, FANS). Airborne weather detection and avoidance system

Far Term

Airspace, Terrain and Obstacle avoidance

Impact with ground objects, airspace infringement due to unstablized approach, loss of flight path performance or pilot loss of situation awareness

Improved Terrain Database, Improved Obstacle Database, Moving Map EVS/SVS E-GPWS enhancements1

Near term

E-GPWS integrated with 3D RNP

Mid term

Airborne Collision Avoidance

Near-mid-air collision loss of flight path performance or airspace infringement (high density airports)

CDTI

RNP, VNAV guidance

Near term

E-GPWS / TAWS enhancements (e.g., Assisted Recovery System)

Near to Mid term

ADS-B In,

TCAS Enhancements (e.g., Assisted Recovery System)

Integrated surveillance and

Mid to Far term3

3 Midterm if the FAA reauthorization bill is enacted which requires the FAA to accelerate planned timelines for integrating Automatic Dependent Surveillance-Broadcast (ADS-B) technology into the NAS, requiring the use of “ADS-B Out” on all aircraft by 2015 and “ADS-B In” on all aircraft by 2018. If not, ADS-B In will be available in the far term.

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collision avoidance systems

Surface Collision Avoidance (Aircraft-based)

Runway incursions 4 at large metroplex airports. Runway excursions5, runway overruns6 or underruns 7 due to unstable approaches. Collisions during taxi operations.

Use of on-board radar to detect other aircraft, vehicles and obstacles on the runway, taxiway, or vertiport. E-GPWS enhancements (e.g., Runway Traffic Advisory System ) Surface Moving Map with own ship position8, CDTI

Near term

Runway Incursion Alerting to Cockpits, ASDE-X.

Mid term

Surface indication and alerting systems using ADS-B In, Out

Mid to far term

Wake avoidance & mitigation

Wake vortex turbulence during mixed fleet ops

GNSS, ADS-B OUT

Mid Term

ADS_B In Mid to Far term

AC-based wake vortex detection (system and sensors).

Far term

Published Routes /Procedures

Reduced Lateral Track Spacing Using RNP

High density terminal area operations

RNP

Optimized Descent Profiles

Medium to high density airport operations

RNP, VNAV, DL, FMS

Mid Term

3D RNP Arrival and Departure Operations

Near-mid-air collision or airspace infringement due to loss of flight path

HUD, EVS, GLS Near to mid term

RNP RNAV, VNAV Mid term

4 Runway incursion: Any occurrence at an airport involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take-off of aircraft. (Source: FAA). 5 Runway excursion: Any aircraft having a loss of directional control either on takeoff or landing which exits a runway other than a designated exit point (e.g. pilots conducting other than full length operations from wrong intersection or overshoot an approach). 6 Runway overrun: When the chosen flight path is flown above the required glide path to where the vehicle lands beyond its intended point of touch down. 7 Runway underrun: When the chosen flight path is flown below the required glide path to where the vehicle lands short of its intended point of touch down. This results in landing short of the runway. 8 Mid term for LCTR.

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performance. (e.g., during steep or spiral approach &departure ops)

guidance, DL, FMS, E-GPWS integrated with 3D RNP.

Reduced Oceanic Separation – Altitude change Pair-wise maneuvers

Near-mid-air collision due to loss of separation minima

FANS, ADS-B, ADS-C, FIS-B, CDTI

Near to Mid term

Negotiated Trajectories

Trajectory Clearance with RTA and Downlink of Expected Trajectory

Near-mid-air collision due to loss of flight path performance

4D FMS, FANS 2/B, TOAC, Secure comm. (UAS)

Mid term

Delegated Separation

Delegated Separation in Flow Corridors

Near-mid-air collision due to loss of separation minima

ADS-B In, CDTI Integrated surveillance and collision avoidance systems

Mid to Far term

Low-Visibility Approach/ Departure/ Taxi

Low-Visibility Approach, Landing, Take-Off

Flight into terrain or obstacles during IMC

E-GPWS / TAWS enhancements, CDTI, HUD

Near term

ADS-B, ESVS, Mid term

ATM Efficiencies

Data Link Departure Taxi Clearance and Pre-departure Clearance Revisions Data Link En Route Clearance Delivery and Frequency Changes Data Link Arrival Taxi Instructions

D_TAXI Mid term

Increase access and throughput at non-towered / uncontrolled airports.

Insufficient ground infrastructure

HUDs, EVS, GLS and airborne avionics for GBAS Cat II/III, Future technologies that reduce dependence on existing ground infrastructure.

Near to Mid term

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VIII. Summary and Conclusion Significant avionics upgrades are necessary to handle advanced vehicle operations in the NextGen Air

Transportation System. We have identified the on-board technology for manned and unmanned aircraft that are anticipated to be available for our advanced vehicles around 2018 to 2025, which is the timeframe that our advanced vehicles will first be introduced into the NAS. We have described the services and infrastructure that will be available in the NextGen ATS and identified the airborne technology enhancements that can mitigate many of the potential hazards generated by the utilization of advanced vehicle performance capabilities on missions within the future NextGen ATS. Similar to the NextGen avionics roadmap developed by the JPDO Aircraft Working Group, we have mapped the required hazard-mitigation avionics against the operational capabilities listed in the NextGen Implementation plan.

Both government and industry investment strategies for the advancement of ground-based and onboard technologies will determine if and when the listed avionics functionality will be available for installation and use on our advanced vehicles. Airborne technology and research initially dedicated to military aircraft, in time, can be hosted on avionics platforms used for civil transport aircraft and vice versa. Technology developed for fixed wing aircraft is often adapted for use in rotorcraft. The latest trend in avionics development is the adaptation of avionics for manned aircraft, to unmanned aircraft systems. Market demands will determine if these technology developments and transfers are cost effective for the OEMs, aircraft suppliers and the vehicle operators. In addition, government investment, standards and mandates can significantly influence the time to market of these new avionics capabilities.

IX. Glossary ACARS Aircraft Communications Addressing and Reporting System ADS-B Automatic Dependent Surveillance-Broadcast ADS-C ARS

Automatic Dependent Surveillance-Contract Assisted Recovery System

ATS Air Transportation System ANSP Air Navigation Service Provider ARINC Aeronautical Radio Incorporated ASDE-X Airport Surface Detection Equipment, Model X ATC Air Traffic Control ATIO Aviation Technology, Integration and Operations ATM Air Traffic Management ATN Aeronautical Telecommunication Network CDA Continuous Descent Arrival CDTI CESTOL

Cockpit Display of Traffic Information Cruise Efficient Short Take Off and Landing

CFIT Controlled Flight into Terrain CMU Communications Management Unit CPDLC DL

Controller Pilot Data Link Communications Datalink

D-TAXI Data Link TAXI ESVS Enhanced and Synthetic Vision Systems EVS Enhanced Vision Systems ETA Estimated Time of Arrival FAA Federal Aviation Administration FANS Future Air Navigation System FIS-B Flight Information Service-Broadcast FMS Flight Management Systems GA General Aviation GBAS Ground Based Augmentation System GLS GPS Landing Systems GNSS Global Navigation Satellite System GPS Global Positioning System

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HMI Human-Machine Interface HUD Head Up Display IMC Instrument Meteorological Conditions JPDO LCTR

Joint Planning and Development Office Large Civil Tilt Rotor

LNAV Lateral Navigation NAS National Airspace System NASA National Aeronautics and Space Administration PBN Performance Based Navigation PFD Primary Flight Display RAAS Runway Awareness and Advisory System RNAV Area Navigation RNP Required Navigation Performance RTA Required Time of Arrival SATCOM Satellite Communications SBAS SMAD SST

Space Based Augmentation System System Modeling and Analysis Division Super Sonic Transport

SUA Special Use Airspace SVS Synthetic Vision Systems SWIM TAWS

System-Wide Information Management Terrain AWareness System

TBO Trajectory Based Operations TCAS Traffic Alert Collision Avoidance System TOAC Time Of Arrival Control UA UAS

Unmanned Aircraft Unmanned Aircraft System

UAT VLJ

Universal Access Transceiver Very Light Jet

VNAV Vertical Navigation

X. References [1] Michael Marcolini, NASA Langley Research Center, private communication, October 2007 [2] M. Blake, F. Wieland, Sensis Corporation, Reston, VA, “Advanced Vehicle Concepts in the Next Generation Air

Transportation System,” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7121.

[3] P. Hollingsworth, M. Kirby, H. Ran, S. Dufresne, and W. Sung, Georgia Institute of Technology, Atlanta, GA , “Advanced Vehicles Modeling for the Next Generation Air Transportation System (NextGen Vehicle Integration NRA),” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7119.

[4] Nagle, G., Elliot, M., and Clarke, J.-P., "New York Metro Airspace Redesign,” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7069.

[5] D. Holl and R. Laroza, ATAC Corporation, Sunnyvale, CA, “Modeling Advanced Vehicle Concepts in the NextGen Terminal Airspace,” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7047.

[6] J. Smith, R. Mediavilla, and F. Wieland, Sensis Corporation, East Syracuse, NY , “Impact of Using Reliever Airports to Absorb Additional Demand in the Potomac TRACON,” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7068

[7] K. Wright, Sensis Corporation, Campbell, CA; and F. Wieland, Sensis Corporation, East Syracuse, NY , “The Effect of Future Vehicles on Controller and Pilot Workload,” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7045.

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[8] V. Volovoi and G. Calanni Fraccone, Georgia Institute of Technology, Atlanta, GA; M. Heddrick, CSSI Inc., Washington, DC; R. Kelley, Sensis Corp., Reston, VA; A. Colon, CSSI Inc., Washington, DC, “Agent- Based Simulation of Off- Nominal Conditions During a Spiral Descent,” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7046.

[9] Dorbian, C., Reynolds, T., Hileman, J., Hollingsworth, P., Pfaender, H., Holl, D., Dinges, E., "Environmental Impact Analysis Framework for NextGen Vehicle Concepts," Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-6982.

[10] Ramadani and L. Vempati, CSSI, Inc, Washington, DC, “The Integration of New Vehicles into the National Airspace System: A Metrics Framework & Trade Study Approach (New Vehicle NRA), ” Proceedings of the 9th AIAA Aviation Technology, Integration, and Operations Conference (ATIO) Conference, 21 - 23 Sep 2009, Hilton Head, SC, AIAA-2009-7120

[11] P. Phelps, P. Bock, C. Gologan, A. Kuhlmann, TU Munchen, Barhaus Luftfahrt, “Impact of ESTOL Capability on Runway Capacity—An Analytical Approach,” Proceedings of the 8th AIAA ATIO Conference, 14-19 September 2008, Anchorage, AK.

[12] NASA Fundamental Aeronautics, the supersonic project, http://www.aeronautics.nasa.gov/fap/supersonic.html [13] “Best Practice for Small Unmanned Aircraft Systems Operations,” RTCA document W1-S2-001-b-SAPP_Best

Practices, September 2006. [14] VERY LIGHT JETS - Several Factors Could Influence Their Effect on the National Airspace System.

http://www.gao.gov/cgi-bin/getrpt?GAO-07-1001. [15] “Cruise Efficient Short Takeoff and Landing Safety Analysis: Initial Hazards Identification,” CSSI Inc., NASA

Ames Research Center Prime Contract # NNA08BA64C report, October 25, 2008 [16] “Very Light Jet Safety Analysis: Safety Analysis,” CSSI Inc., NASA Ames Research Center Prime Contract #

NNA08BA64C report, January 30, 2008 [17] “Unmanned Aerial Systems Safety Analysis: New Hazards Identification,” CSSI Inc., NASA Ames Research

Center Prime Contract # NNA08BA64C report, March 19, 2009 [18] “Supersonic Transport Safety Analysis: New Hazards Identification,” CSSI Inc., NASA Ames Research Center

Prime Contract # NNA08BA64C report, June 11, 2009 [19] “Large Civil Tilt Rotor Safety Analysis: Initial & New Hazards Identification,” CSSI Inc., NASA Ames

Research Center Prime Contract # NNA08BA64C report, June 29, 2009 [20] R. Weber, “Avionics Roadmap for CESTOL Aircraft in NextGen,” contract deliverable on NASA Ames

Research Center Prime Contract # NNA08BA64C, October 2008. [21] R. Weber, “Avionics Roadmap for Very Light Jets in the Next Generation Air Transportation System,” contract

deliverable on NASA Ames Research Center Prime Contract # NNA08BA64C, February 2009. [22] R. Weber, “Avionics Roadmap for Uninhabited Aircraft Systems in the Next Generation Air Transportation

System,” contract deliverable on NASA Ames Research Center Prime Contract # NNA08BA64C, June 2009 [23] R. Weber, “Avionics Roadmap for Large Civil Tilt Rotors in the Next Generation Air Transportation System,”

contract deliverable on NASA Ames Research Center Prime Contract # NNA08BA64C, August 2009. [24] R. Weber, “Avionics Roadmap for Supersonic Transport Aircraft in the Next Generation Air Transportation

System,” contract deliverable on NASA Ames Research Center Prime Contract # NNA08BA64C, October 2009.