Bro Vempati
April 2019
Urban Air Mobility
Airspace Integration
Operational Concepts and
Exploration Appoaches
Approved for Public Release –
Distribution Unlimited – 19-00667-9
©2019 The MITRE Corporation. All rights reserved.
Brock Lascara
Andrew Lacher
Matthew DeGarmo
David Maroney
Rick Niles
Lakshmi Vempati
June 2019
© 2019 The MITRE Corporation. All Rights Reserved. 2
Approved for Public Release. Distribution Unlimited. 19-00667-9
This page intentionally left blank.

© 2019 The MITRE Corporation. All Rights Reserved. 3
Approved for Public Release. Distribution Unlimited. 19-00667-9
Introduction to UAM Concept ………………………………………………………………………………………………………. 4
Challenges Under Today’s Constructs ……………………………………………………………………………………………. 4
Airspace Integration Framework …………………………………………………………………………………………………… 6
Basic Principles for UAM Airspace Integration …………………………………………………………………………….. 6
Proposed Operational Concept Components to Enable UAM Airspace Integration ………………………….. 6
Augmented Visual Flight Rules ………………………………………………………………………………………………. 7
Dynamic Delegated Corridors ………………………………………………………………………………………………… 8
Decision Support Services for Automation …………………………………………………………………………….. 10
Performance-Based Operations ……………………………………………………………………………………………. 10
Airspace Integration Example Concept Description ……………………………………………………………………. 11
Concept Exploration and Evaluation …………………………………………………………………………………………….. 14
Lab Evaluation Opportunities ………………………………………………………………………………………………….. 14
MITRE IDEA Lab ……………………………………………………………………………………………………………………… 14
Summary ………………………………………………………………………………………………………………………………….. 15
References ……………………………………………………………………………………………………………………………….. 16
© 2019 The MITRE Corporation. All Rights Reserved. 4
Approved for Public Release. Distribution Unlimited. 19-00667-9
Introduction to UAM Concept
Urban Air Mobility (UAM) is an industry term used to describe a system that enables on-demand, highly
automated, passenger- or cargo-carrying air transportation services. The industry vision involves
leveraging new vehicle designs and system technologies, developing new airspace management
constructs and operational procedures, and embracing the sharing and services economy to enable a
new transportation service network.
Aircraft manufacturers and service providers expect to use electric vertical takeoff and landing (eVTOL)
technologies to enable runway-independent operations. They also expect to operate with very high
degrees of automation, up to and including fully self-piloted aircraft1
. Most operators envision an ondemand service, enabling growth up to 100s or 1,000s of simultaneous operations around a
metropolitan area at altitudes up to 5,000 feet and speeds up to 150 knots. These aircraft would carry
cargo or 1-5 passengers on short-range trips (e.g. less than 100 km) [1].
These operational characteristics will prevent an immediate deployment of full-scale UAM operations
since existing airspace procedures, regulations, policies, and structures will not necessarily
accommodate the envisioned operations. As an example, without an on-board pilot, compliance with
visual flight rules and see and avoid requirements will not be feasible. Most proponents propose
operating at a limited scale, some even proposing to begin with pilots in the aircraft much like current
day helicopter operations, until the necessary constructs evolve to enable high-density self-piloted
operations. This paper explores the challenges of integrating highly automated UAM operations into the
National Airspace System (NAS). It then presents some operational concepts that could enable safe
integration of UAM into the NAS. The UAM industry is beginning to explore and socialize ideas around
UAM integration challenges. [2] [3] [4]. This paper offers future integration principles and presents a
postulated operational framework that utilizes specific aviation concepts to enable safe and efficient
airspace integration. The described concepts are not intended to define the exact solution space for
future operations. However, this framework can serve as a starting point for concept evaluations, which
then inform the development of systems and solutions that enable initial operations.
Challenges Under Today’s Constructs
In today’s operations, two flight rules constructs are used to mitigate risks of collision and ensure a
smooth flow of traffic: Visual Flight Rules (VFR) and Instrument Flight Rules (IFR).
With VFR, the pilot must be able to operate the aircraft both with visual reference to the ground, and to
visually avoid terrain, obstructions and other aircraft. The concept of Visual Meteorological Conditions
(VMC) is used to quantify the cloud clearance, ceiling, and visibility requirements needed for a pilot to
see the ground, obstructions, and other aircraft. The key to using VFR is having a human pilot onboard
to use their eyes, brain, knowledge, experience, and training to mitigate risks of collision and
inadvertent entry into unsafe meteorological situations.

Many in the UAM industry are using the term “self-piloted”, to refer to an aircraft that does not have an onboard pilot or a remote pilot who is actively engaged in the individual flight. The aircraft is essentially piloting itself
via automation. Most proponents envision a human will likely be remotely supervising potentially large numbers
of simultaneous operations.
© 2019 The MITRE Corporation. All Rights Reserved. 5
Approved for Public Release. Distribution Unlimited. 19-00667-9
Under operating conditions where the pilot cannot safely operate as VFR using visual references, the
pilot conducts flight under IFR using other mechanisms to help mitigate risks of collision. Since visual
reference may not be adequate, cockpit instruments are used to support navigation. However, as in
VFR operations, responsibility for aircraft avoidance remains with the pilot, though this function is
largely managed by Air Traffic Control (ATC) through separation services. The pilot must file a flight plan
with ATC and will receive and must follow instructions provided by ATC to maintain separation (unless
flight is within Class G airspace). Since IFR aircraft are sharing telemetry (squawking) and are
communicating on voice channels (talking), ATC has increased situational awareness of other traffic that
the IFR aircraft pilot may not have (e.g., due to lack of a visual reference when in clouds)2
. The key to
using IFR is having ATC provide separation services to aid a pilot that may not be able to see other traffic
and mitigate risk of collision on their own.
Airspace is divided into six categories, with differing operational requirements and levels of ATC service
provision. Airspace classes include Class A, B, C, D, E, and G, with Class A being the most restrictive and
Class G being the least restrictive in terms of requirements. In some airspace (e.g., Class B), separation
services are provided regardless of whether the flight is IFR or VFR because the traffic may be too dense
to self-separate. In other more lightly travelled airspace (e.g., Class G), separation services are not
provided, and the airspace is considered “uncontrolled”.
Unmanned Aircraft Systems (UAS) Traffic Management (UTM) is another construct currently under
development for use by UAS operating at low altitudes (e.g. below 400 feet). UTM provides a set of
traffic management services via a federated group of UTM Service Suppliers (USS), comparable to
traditional ATC services provided to IFR and VFR aircraft.
Current flight rules (VFR, IFR), and UTM services impose the following limitations on envisioned UAM
 Without a trained human pilot onboard the UAM aircraft, the flight will not be able to meet 14
Code of Federal Regulations (CFR) Part 91 using VFR or IFR, because no human entity would be
seeing, avoiding, and following right of way rules.
 If the UAM automation is responsible for navigation, the automation will not be able to reliably
“listen” and respond to instructions provided by ATC voice.
 At the expected volume of UAM operations, the standard separation distance (typically 3 NM)
provided by ATC separation services will be too large to make envisioned operations viable.
 At the expected volume of UAM operations, ATC will not be able to reliably manage and provide
ATC services to such a large scale of traffic.
 Since UAM operations are expected to occur above 400 feet, the current scope of UTM services
would not be applicable.
 UAM aircraft operating below 400 feet may not be able to leverage some existing UTM services,
since the service reliability designed for small UAS operations may need to be modified to meet
the safety requirements for provision to passenger carrying UAM.

In some regions of Class D airspace where aircraft are not required to equip with a transponder, ATC may not
have a “full picture” of the traffic situation. Oftentimes, procedural mechanisms such as specified departure times
are used to mitigate this reduced situational awareness.
© 2019 The MITRE Corporation. All Rights Reserved. 6
Approved for Public Release. Distribution Unlimited. 19-00667-9
Airspace Integration Framework
Integrating autonomous systems into the existing National Airspace System (NAS) is challenging but not
impossible. The following mechanisms can enable airspace integration without requiring long lead-time
changes such as new rulemaking or FAA capability development.
 Utilizing existing procedural constructs,
 Creating additional decision support services, and
 Allowing for flexible understanding of the intent of existing regulatory structures
These mechanisms can enable initial UAM operations to integrate safely and efficiently into the NAS
without significant adverse impacts to existing operators and traffic management providers.
While other more significant changes to the design of the NAS may facilitate better flexibility of future,
more mature autonomous operations, these changes are not discussed in detail in this framework.
Examples of significant changes include redefining airspace classes and integrating manned and
unmanned traffic into a common traffic management system. Exploratory research should begin to
identify the scope of solutions that involve major changes to the NAS, however rulemaking and
government investments in these major changes should wait until a common vision for the future is
agreed upon.
Basic Principles for UAM Airspace Integration
The following principles guided the development of potential operational concepts to enable UAM
airspace integration:
 Legacy IFR and VFR traffic should operate under the same rules as they do today.
 Minimal additional requirements should be imposed on existing ATC services provided today
(any additional requirements are mostly related to off-nominal situations).
 Procedures for UAM operators should provide flexibility to address the needs of a given
airspace, and scalability to enable increasing operational tempo.
 Equitable rules and airspace access should be established that maximize routing preference for
both legacy operators and UAM operators.
Proposed Operational Concept Components to Enable UAM Airspace Integration
Based on the challenges of today’s constructs, and the principles for future integration, the following
section proposes a set of operational concept components that when combined can help enable
effective integration of automated UAM operators into the NAS with minimal changes to legacy
operations. Many questions arise from these concepts regarding topics such as roles, responsibilities,
interfaces, and infrastructure. Each of the four main concept components will be explored in more detail
below. Under each of the main concept components, there are a set of boxed bullet points which
identify open questions and considerations for future research and analysis.
The following are the four main concept components which are discussed in more detail in this paper:

  1. Augmented Visual Flight Rules
  2. Dynamic Delegated Corridors
  3. Automated Decision Support Services
  4. Performance-Based Operations
    © 2019 The MITRE Corporation. All Rights Reserved. 7
    Approved for Public Release. Distribution Unlimited. 19-00667-9
    Augmented Visual Flight Rules
    Augmented VFR is a concept that enables UAM aircraft to operate just like piloted aircraft operate today
    using VFR. Augmented VFR requires an update to 14 CFR Part 91.113 such that see and avoid can be
    achieved through a functionally equivalent sense and avoid capability leveraging technology in a fully
    automated manner (i.e., without the pilot in the loop3
    ). In other words, the intent of Part 91 remains the
    same, however the original mechanism (human eyes and brain) can now be replaced with a certified
    industry-developed capability that achieves the same intent. Certified systems would manage safe
    separation and avoidance maneuvers without needed input from a pilot, however monitoring and
    override functions may remain. This rules update may specify a different set of weather minimums (i.e.
    Augmented VMC) for certified equipment than current definitions of VMC used by piloted aircraft today.
    However, the rules update would not be expected to change the right of way rules. An external observer
    watching an aircraft’s flight movement and avoidance decisions should not be able to determine if the
    aircraft had a human pilot or was using certified augmented VFR equipment. The sense and avoid
    capability may simply be a self-contained system onboard the aircraft or may be a system that leverages
    input from distributed systems including components on the ground (e.g., a shared radar surveillance
    network that shares traffic situation data suitable for the intended function with airborne aircraft).
    These systems would be built to industry consensus performance standards, certified by the FAA, and
    meet the intent of visual flight rules as currently defined in Part 914
    . The technology that enables the
    “sense and avoid” function associated with Augmented VFR will be referred to as Detect and Avoid
    (DAA) for the purposes of this paper.
    Today, in some airspace, VFR flights may fly through specially designed corridors, often referred to as
    VFR corridors and VFR flyways. VFR corridors enable VFR traffic to fly within controlled airspace
    (typically Classes B, C, and D) without requiring communications with ATC.5
    VFR flyways are general
    flight paths not defined as a specific course, that are used to plan flight into, out of, through or near
    complex terminal airspace to avoid Class B airspace [5].6
    These routes are often designed with specific
    local procedures, such as designated altitude maximums or transmission on certain frequencies.
    Augmented VFR equipment will need to be designed to meet all established local procedures for these
    flight corridors. This might include use of automated voice callouts to indicate current position, or
    intentions upon leaving the corridor.
    Today’s VFR corridors and VFR flyways are designed such that ATC does not have to worry about
    steering IFR aircraft away from the corridor, because the corridor is not placed near typical instrument
    procedures. In other words, corridor locations and procedures are designed so it would be very unlikely
    that ATC would need to provide services to VFR flights in the corridor. The next section presents a future
    concept for an additional type of corridor available for automated aircraft.

A pilot-in-the-loop system is a system where a human must interact with the system for it to be able to perform
or control actions. In this case there is no need for any human action to ensure successful execution of a sense and
avoid capability.
Since rule changes can take many years, initial operations may occur under operational waivers. This would
provide a near-term solution.
These corridors can help expedite the flow of VFR traffic rather than require them to wait for entry clearance or
fly all the way around the controlled airspace.
They are often used to help establish an orderly flow of traffic around busy airspace without requiring contact
with ATC.
© 2019 The MITRE Corporation. All Rights Reserved. 8
Approved for Public Release. Distribution Unlimited. 19-00667-9
While Augmented VFR equipment will be designed to follow right of way rules established under Part
91, some very rare traffic situations may require temporarily breaking a rule (e.g., not able to alter
course to the right when approaching head on) in order to achieve the safest operating condition.
Today, pilot’s use best judgement to determine the safest course of action when two rules may be in
conflict. Tomorrow’s automation decisions will need to consider best course of action during conflicting
logic situations.
Discussion Items for Future Exploration:
 Future research should identify the scope of changes needed to Part 91 and other procedures to
enable Augmented VFR.
 Identification of the performance standards needed for Augmented VFR Detect and Avoid
 Future research should identify impacts on ATC’s decision-making sequence if additional UAM
aircraft fly within an existing VFR corridor/flyway or if new corridors or flyways solely for
Augmented VFR would be appropriate.
 Today’s VFR corridors/flyways may not have been designed with future UAM operators in mind.
Future research should consider whether current designs are sufficient to accommodate UAM
aircraft with Augmented VFR equipment.
 Future studies should explore the range of procedural possibilities for existing VFR
corridors/flyways and identify any unique local procedures that would be difficult to design into
Augmented VFR equipment.
 Future research should explore the avoidance priorities for maintaining flight safety and
meeting the intent of Part 91 with Augmented VFR equipment.
 Explore software certification frameworks and operational safety assurance frameworks for
Augmented VFR functionality.
Dynamic Delegated Corridors
The Dynamic Delegated Corridors (DDCs) concept is intended to enable UAM aircraft to operate in busy
airspace by defining specific corridors that enable procedural separation from conventional aircraft
operating under IFR flight rules. The concept also defines a set of rules and procedures to help
coordinate traffic flows within that corridor. DDCs are volumes of airspace designated for flight using an
established set of procedures and rules. DDCs are similar to the notion of VFR corridors and VFR flyways,
except todays VFR corridors and flyways are rather static. The status of Dynamic Delegated Corridors
will vary over time, enabling them to be opened and closed depending upon environmental conditions
(e.g., wind, weather), UAM traffic density/demand, airport configurations, and legacy air traffic. Their
design assumes that aircraft which utilize them will be equipped with flight automation technologies
that may enable different procedural mechanisms than are typically available for conventional aircraft.
DDCs would also expand the set of corridors available so that UAM aircraft are not limited to the
locations where VFR corridors are defined today. The following list of assumptions are used to scope the
DDC concept:
 DDCs are established and designed with input from a variety of stakeholders, such as local air traffic
managers, city planners, military, etc. Design criteria considers local traffic patterns, flight-deck
automation capabilities, noise and environmental concerns, and other local hazards.
© 2019 The MITRE Corporation. All Rights Reserved. 9
Approved for Public Release. Distribution Unlimited. 19-00667-9
 DDCs use clearly defined boundaries that can be digitally communicated (as opposed to general
flight regions like a VFR flyway). The exact size, shape, and applicability time that defines a DDC may
change over time, hence the term dynamic. DDCs may have a standard daily transit availability
schedule, however local air traffic managers have the ability to open/close the corridor as needed to
ensure safety of the airspace.
 Conventional IFR and VFR traffic are not restricted from entering DDCs but during periods where
UAM aircraft are actively using the DDC for Augmented VFR operations, controllers will try to avoid
clearing aircraft into that DDC. Some conventional aircraft may choose to equip with technology to
enable smooth integration into the DDC when operationally necessary.
 DDCs may be defined within the boundaries of Class B, C, and D airspace. ATC treats DDCs just as
they treat VFR corridors (i.e. ATC does not manage traffic nor provide separation services to aircraft
in the DDC).
 DDCs may also be defined within the boundaries of Class E airspace, by an automated traffic
management service (discussed in the next section).
 For some DDCs, intent to fly within a DDC should be coordinated via a certified automated traffic
management service (described in the next section). Depending on local DDC procedures, entry and
exit from a DDC may require clearance from an automated traffic management service.
 Flight operations in a DDC occur under the flight rules established in 14 CFR Part 91 Subpart B –
Flight Rules (or any future updates to those rules). Local procedures may enable very small
separation distances between appropriately equipped aircraft as long as the intent of the see and
avoid clause is maintained.
 DDCs are designed to minimize crossing busy human-piloted VFR traffic corridors, however VFR
traffic is not prohibited from entering a DDC.
Discussion Items for Future Exploration:
 Future research should explore the airspace management conditions under which DDCs are
warranted, as opposed to flying on company routes or using established VFR corridors.
 Future research should explore the impacts of dynamic flexibility on air traffic manager
workload and the scope of tools needed to support dynamic temporal flexibility.
 Future analysis should explore how DDC placement impacts ATC monitoring tasks to ensure IFR
aircraft do not enter a DDC.
 Future research should explore how DDCs are defined in Class D airspace regions that don’t
have radar service, but rather manage separation by controlling flight rates.
 Future research should explore what information (e.g., position and traffic count) should be
available to local air traffic managers, and how this information should be made available.
 Future research should explore what navigation performance requirements (i.e., accuracy of
containment) will be necessary for aircraft transiting a DDC.
 Contingency procedures will be needed for when an automated aircraft loses link while flying in
the DDC.
 Future research should explore the extent of coordination needed with air traffic managers
when defining a DDC in Class E airspace.
 Future research should explore the scope of local procedures that can be created to help dictate
traffic rates within a DDC. Some procedures may be prevalent enough that they could be
© 2019 The MITRE Corporation. All Rights Reserved. 10
Approved for Public Release. Distribution Unlimited. 19-00667-9
established as a new set of flight rules regulated under Part 91. Possibly called Corridor Flight
Rules – these would only be applicable within a DDC for use by certified autonomous systems
and would be used instead of VFR or IFR.
 Future research should explore the viable traffic management solutions given a range of
expected traffic densities within a corridor. Solutions may involve a centralized automated
traffic control system, or a simple entry metering solution with free flight once in the corridor.
 Future research should explore the design of DDCs to minimize interactions with existing VFR
traffic flows and any situational awareness tools made available for conventional VFR traffic to
be aware of the location of DDCs.
Decision Support Services for Automation
UAM aircraft will need access to a wide variety of collaborative decision support information to enable
safe and efficient flows of traffic. Decision support services are provided through an open architecture
information exchange and may communicate both safety critical and safety enhancing information.
Examples include traffic location, DDC status, meteorological information, obstruction locations, traffic
coordination, and landing site information. The architecture for service provision may be similar to and
possibly share elements of the UAS Traffic Management System (UTM) architecture. The main
difference from UTM is that UAM services will be applicable for automated aircraft operations with
longer flight distances, higher altitudes, and more stringent safety assurance applications than existing
UTM services that focus on non-passenger carrying, beyond visual line of sight operations below 400
feet. Depending on their location and operation type, automated aircraft may be required to provide
identification, intent, and telemetry information over the information exchange link.
Discussion Items for Future Exploration:
 Decision support information for UAM operations will need to leverage and exchange
information with existing UTM services and conventional ATC services. The scope and method of
information exchange between the three environments needs to be explored.
 The scope and criticality of data services will need to be explored. In addition, service provision
responsibilities should be explored to identify which services are provided by FAA and which
services are provided by qualified industry providers.
 A variety of communications links and exchange protocols will be possible. Additional research is
needed to scope the information exchange architecture and define the criticality and
performance of each provided service.
 Many UAM operations will occur in airspace regions where a Mode C transponder is required
today and Automatic Dependent Surveillance – Broadcast (ADS-B) will be required (starting in
2020). Future research should identify which communication links can support identification and
tracking requirements and explore the performance impacts on those links at various traffic
Performance-Based Operations
The performance-based operations concept is intended to enable growth and scalability of UAM
operations as aircraft are equipped with better performing technologies. UAM operators equipped with
the best technologies will, in some cases, be able to fly the most efficient company-preferred route.
Examples of equipage differentiating technologies include navigation precision technology, DAA
technology, noise reduction technology, and vehicle to vehicle (V2V) communications technology. To
© 2019 The MITRE Corporation. All Rights Reserved. 11
Approved for Public Release. Distribution Unlimited. 19-00667-9
best enable performance-based operations, careful consideration should be placed on understanding
the impact of mixed-equipage operations and whole-system efficiency impacts. While better performing
aircraft will see benefits, lesser performing operators should still be able to meet their operational
business case.
Performance-based operations may open some areas of flight and some DDCs to UAM aircraft with a
certain level of equipage. Some DDCs may be open to aircraft equipped with a specified level of
navigation precision, providing more direct routing options to these aircraft. For example, greater
navigation precision may be needed to enable flight operations through a narrow corridor. Some DDCs
may be open to aircraft equipped with a specified time of arrival precision, enabling high throughput
operations through a corridor. Aircraft with significantly different speed capabilities may determine
throughput performance through a DDC.
Better performing DAA and V2V technologies may enable lower separation requirements within a given
area of flight. For example, an aircraft with a high performing V2V equipage may be able to fly within
100 feet of another aircraft with the same equipage but may have to stay at least 1,000 feet away from
a different aircraft with lower performing equipage. In the future, aircraft performance could enable
dynamic separation standards.
Additionally, some DDCs may be open to aircraft meeting certain noise emission thresholds.
Discussion Items for Future Exploration:
 Future work should identify the key performance factors that differentiate better performing
UAM operations, the technology life cycles driving the differences, and the forces supporting
convergence of technologies.
 Future research should identify the scope of procedure design opportunities given the key
performance factors.
 Future research should identify which performance capability information needs to be shared
with other stakeholders. For example, conventional air traffic management systems may benefit
from access to the performance capabilities of UAM aircraft to support decision making (e.g. to
support on/off display indications depending on performance)
 Future work should develop a concept of operations for performance-based separation
Airspace Integration Example Concept Description
Figure 1 shows an example flight path of an automated UAM aircraft operating through a variety of
airspace classes and dynamic delegated corridors. A detailed concept description is provided for each
indicated segment of flight. Segments are given a descriptive indication C# to represent flight through
corridors and R# to represent flight along company-preferred routes outside of corridors.
© 2019 The MITRE Corporation. All Rights Reserved. 12
Approved for Public Release. Distribution Unlimited. 19-00667-9
Figure 1: Notional Depiction of Airspace Integration Concepts
© 2019 The MITRE Corporation. All Rights Reserved. 13
Approved for Public Release. Distribution Unlimited. 19-00667-9
 C1) Aircraft depart and arrive from a vertiport in Class G airspace. When the vertiport is busy and
has operations from many different UAS and UAM operators, a decision support system provides
traffic management services in and out of the vertiport. During busier times, the system may define
a DDC for departures and arrivals to help establish procedural separation between unmanned
aircraft in the region. Aircraft planning to fly within the DDC must file intent and coordinate a
trajectory with the decision support system and follow the applicable procedures established for
that corridor.
 R1) The UAM aircraft gains altitude, exits the departure DDC, and enters Class G airspace. As the
aircraft keeps climbing and passes 700 feet, it enters Class E airspace and reaches its cruise altitude
of 1,500 feet. The aircraft is equipped with augmented VFR technology and flies a companypreferred route towards an established VFR corridor. It uses DAA equipment to avoid other aircraft
as if it were like a piloted aircraft following visual flight rules. Under the Mode C veil, the UAM
aircraft is broadcasting ADS-B. The broadcast includes an indication that the aircraft does not have a
human pilot onboard and is using augmented VFR technology.
 C2) The UAM aircraft has an option to either fly around Class D airspace, or if equipped, fly through
a VFR corridor that has been developed by the local air traffic manager. Flight within this corridor
does not require ATC communication, however a specified set of procedures must be followed. The
UAM aircraft must be equipped with the knowledge of the procedures of this specific VFR corridor
in order to enter.
 R2) The UAM aircraft exits the VFR corridor and re-enters Class E airspace. As before, it uses
augmented VFR technology and flies a company-preferred route continuing towards its destination.
It then approaches a busy section of Class E airspace under the ‘Mode C Veil’7
 C3) In a portion of the Class E airspace that is known to be particularly busy (e.g., within the Mode C
Veil), an automated decision support system has dynamically established and published a DDC.
Aircraft follow specific procedures and speeds along this corridor to help coordinate and smooth the
flow of traffic. The UAM aircraft is not required to fly along this corridor, but determines it will get
some operational benefit, since it will be less likely to have to vector around other traffic when
flying within the corridor. The decision support system notifies ATC that the corridor has been
established, and ATC may aid IFR aircraft in avoiding that corridor. As the UAM aircraft nears the exit
point of the DDC, it approaches Class B airspace and must make a routing decision.
 C4/5/6) The UAM aircraft can either fly around Class B airspace or enter Class B airspace through a
DDC. Specific equipage requirements are in place in order to enter this DDC, including a minimum
navigation precision requirement and knowledge and competency to abide by all procedures
associated with this DDC. The aircraft enters the DDC without notifying ATC and continues flying
towards the destination. The DDC then splits into two different corridors. Corridor C5 has more
strict navigation performance requirements and enables a shorter flight path than Corridor C6. Since
the UAM aircraft is equipped with the needed equipment to fly in C5, it chooses that corridor and
continues towards its destination. The aircraft then reaches the end of the corridor and exits Class B
airspace back into Class E airspace.
 R3) As before, the UAM aircraft uses augmented VFR technology and flies a company-preferred
route continuing towards its destination.
 R4) The UAM aircraft descends towards the vertiport and transitions from Class E to Class G
airspace. No DDCs are in place at this vertiport, and the UAM aircraft uses augmented VFR

The ‘Mode C Veil’ is the informal name for the airspace within 30 NM of a Class B airport in the U.S. within which
use of a transponder or ADS-B is required.
© 2019 The MITRE Corporation. All Rights Reserved. 14
Approved for Public Release. Distribution Unlimited. 19-00667-9
technology and UTM traffic information services to avoid other UAM aircraft and other small UAS in
the area.
Concept Exploration and Evaluation
Many of the questions and research topics raised above can be explored in an experimental
environment where concepts and possibilities can be envisioned, analysis conducted, and consensus
reached among the diverse aviation stakeholder community.
Lab Evaluation Opportunities
The primary objectives of a lab activity are visualizing and exploring the concept of allowing augmented
VFR flights to fly through a variety of the following airspace situations.
 Existing VFR corridors
 Existing VFR flyways
 Class E airspace
 Dynamic Delegated Corridors in Classes B, C, D airspace
 Class G airspace below 400 feet with frequent small UAS operations
Research questions include:
 What are the impacts to air traffic managers controlling that airspace?
 What are the impacts to other VFR traffic in that airspace and other IFR traffic in the vicinity?
 What decision support capabilities may be needed for ATC? For UTM? For other operators?
 What procedural changes/additions are needed to enable the operation?
Visualizing these concepts and performing thought exercises with a variety of stakeholders will help
refine concept details, identify needed decision support information, identify needed information flows,
and explore potential roles and responsibilities for future operations.
These concepts can be explored across a range of different traffic situations reflecting anticipated
technology maturation and traffic densities. This will help provide an understanding of possible
implementation timelines and system needs over time. Visuals can help identify the range of viable
routes (of various types) between select origin/destination pairs in a metro region, given the concepts
presented in this paper.
These concepts can also be explored in the context of important off-nominal situations. For example,
visualizing an aircraft deviating from a DDC possibly into controlled airspace can help understand the
sequence of events to mitigate safety hazards and rectify the situation.
One such environment is the MITRE Integrated Demonstration and Experimentation for Aeronautics
(IDEA) Laboratory.
For the past 20 years, MITRE has been using the IDEA Lab primarily located in McLean, Virginia as a
robust environment capable of evaluating a range of exploratory concepts, while also being realistic
enough to enable high fidelity simulations. The IDEA Lab’s integrated capabilities, such as numerous
cockpit simulators, a Tower simulation, Air Traffic Control decision support displays, and instances of the
© 2019 The MITRE Corporation. All Rights Reserved. 15
Approved for Public Release. Distribution Unlimited. 19-00667-9
FAA’s traffic management capabilities (e.g. Time Based Flow Management, TBFM) enable human-in-theloop (HITL) simulations, demonstrations, and visualizations.
Working in the IDEA Lab together with the Federal Aviation Administration, National Air Traffic
Controllers Association, Air Line Pilots Association, civil aviation authorities of various countries, and
other organizations, MITRE has helped improve aerospace systems in a number of key areas, such as
airspace redesign, controller training prototypes, airport/runway siting, and incorporating UAS into the
Figure 2: Picture of the Tower environment in the IDEA Lab.
The existing infrastructure and flexible design of the IDEA Lab provides an excellent environment to
evaluate and iterate on the airspace integration concepts discussed in this paper. The IDEA Lab provides
an environment for all parties to share the experience of a proposed concept, discuss their perspectives
on workload, communication, safety, efficiency, roles and responsibilities, as well as other topics.
Visualization, iterative changes, and evaluations allow the parties to come to an agreement quickly and
lead to faster implementation of beneficial enhancements.
In this paper we lay out four concept components that could enable the routine integration of UAM
traffic in existing terminal area airspace with minimal operational changes to existing rules, policies, and
procedures and with minimal disruption to existing flight operations. However, additional research is
required to further develop, explore the implications, and evaluate the feasibility of such concepts.
Leveraging simulation capabilities such as MITRE’s IDEA lab is one such means to explore and evaluate.

© 2019 The MITRE Corporation. All Rights Reserved. 16
Approved for Public Release. Distribution Unlimited. 19-00667-9
[1] B. Lascara, T. Spencer, M. DeGarmo, A. Lacher, D. Maroney and M. Guterres, “Urban Air Mobility
Landscape Report,” MITRE, McLean, 2018.
[2] Airbus, “Blueprint for the Sky: The Roadmap for the Safe Integration of Autonomous Aircraft,” A^3
by Airbus LLC, Sunnyvale, 2018.
[3] EmbraerX, Atech and Harris Corporation, “Flight Plan 2030: An Air Traffic Management Concept for
Urban Air Mobility,” EmbraerX, São Paulo, 2019.
[4] D. P. Thipphavong, R. D. Apaza, B. E. Barmore, V. Battiste, B. Burian and et. al., “Urban Air Mobility
Airspace Integration Concepts and Considerations,” in AIAA Aviation Forum, Atlanta, 2018.
[5] U.S. Department of Transportation, “Order JO 7210.3W Section 5. Charted VFR Flyway Planning
Chart Program,” FAA, 2010.