UAS Traffic Management (UTM) Technical 

Capability Level 3 (TCL3) Flight Demonstration: 

Concept Tests and Results 

Jeffrey Homola Lynne Martin 

NASA Ames Research Center NASA Ames Research Center 

Moffett Field, CA, USA Moffett Field, CA, USA 

jeffrey.r.homola@nasa.gov lynne.martin@nasa.gov 

Abstract—Over the course of three months in 2018, NASA, in 

collaboration with the six FAA UAS Test Sites and industry 

partners, conducted its Technical Capability Level 3 (TCL3) flight 

testing as part of its UAS Traffic Management (UTM) research. A 

set of five tests were developed to address elements of the UTM 

concept that involved Beyond Visual Line of Sight landings, 

Contingency Management, development of a Public Portal for 

UTM information, Sustained Operations, and Unauthorized 

Airspace Entry/Exit. Each of the tests were successfully performed 

and unique insights were gained in each of the testing areas. 

Keywords—NASA, FAA UAS Test Sites, UTM, TCL3 

I. INTRODUCTION 

NASA has been engaged in research focused on enabling the 

commercial application of small Unmanned Aircraft Systems 

(UAS) that is safe, scalable, equitable, and efficient. This effort 

falls under the UAS Traffic Management (UTM) project, which 

has taken the approach of defining operating environments 

according to their relative risks and complexity in order to scope 

the research into distinct Technical Capability Levels (TCL). 

This approach resulted in the definition of four TCLs that 

encompass UTM environments ranging from low density, rural 

operations as part of TCL1 to the high density, urban operations 

envisioned in TCL4 [1]. Since 2015, live flight demonstrations 

have been conducted as part of each TCL that highlighted the 

key elements of the respective capability level in terms of the 

concept, reference technologies, and procedures [2-5]. The 

TCL3 demonstration consisted of tests that were grouped 

according to the focus areas of the joint FAA and NASA 

Research Transition Team: Data Exchange Working Group 

(DWG), Sense and Avoid (SAA), Communications and 

Navigation (C&N), and the Concepts and Use Cases Working 

Group (CWG) [6]. 

The CWG is focused on the collaborative development of 

the UTM concept between NASA and the FAA. The tests 

included in TCL3 as part of the CWG -referred to as the CON 

tests- were intended to explore specific elements in order to 

inform the refinement of the UTM concept as it relates to TCL3 

and the envisioned environment. This paper will describe the 

tests conducted as part of the CWG contribution to TCL3 and 

report on the results and lessons learned from those tests. For a 

broader overview of the overall testing, refer to [7]. 

Michele Cencetti Arwa Aweiss 

Universities Space Research NASA Ames Research Center 

Association/NASA Ames Moffett Field, CA, USA 

Research Center arwa.s.aweiss@nasa.gov 

Moffett Field, CA, USA 

michele.cencetti@nasa.gov 

II. TEST OVERVIEWS 

In the spring of 2018, overall TCL3 testing was conducted 

at six FAA UAS Test Sites. The CON tests were conducted at 

5 of the 6 test sites with involvement from multiple industry 

partners and technologies. A total of 5 tests were constructed 

based on areas of focus to advance the further development of 

the UTM concept. The tests described below were all 

performed at different test sites in different combinations, 

which provided the opportunity for a broader understanding and 

assessment of the concept elements. 

A. CON 1: Beyond Visual Line-of-Sight Landing 

CON 1 focused on the performance of operations that 

involved landings and subsequent take-offs while Beyond 

Visual Line-of-Sight (BVLOS). The objective for CON 1 was to 

test the operation planning, procedures, and the technology 

needed to enable a BVLOS landing, take-off, and return to base 

in a variety of live environments. This test built upon previous 

TCL testing where BVLOS operations were conducted but 

landings and takeoffs while BVLOS were not required nor a 

focal point. The ability for operators to perform the full sequence 

of maneuvers covered in CON 1 while connected to a USS and 

exchanging data is considered an enabler for safe BVLOS 

operations with shared awareness available to other airspace 

entrants mediated by the UTM ecosystem. 

B. CON 2: Contingency Management 

The performance of CON 2 was intended to provide an 

understanding of the procedures and information exchanges 

needed in handling contingency situations within a UTM 

environment. The tests involved operations in which an 

emergency situation was injected into the scenario that 

necessitated the activation and announcement of a prepared 

contingency. As part of TCL3, changes were made to the UTM 

Application Programming Interface (API) that provided 

operators the ability to include contingency plan information 

with their operation submissions for reference to pre-defined 

plans (e.g., loiter points, landing areas). New messages were 

also implemented to allow operators to communicate the 

initiation and cancellation of contingency plan procedures to 

other airspace users via their supporting USS for awareness and 

subsequent assessment in determining required actions. 

XXX-X-XXXX-XXXX-X/XX/$XX.00 ©20XX IEEE 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C. CON 3: UTM Public Portal 

The focus of CON 3 was on the development of a browser 

or app-based interface for a member of the general public to 

access appropriate UTM information. This test provided an 

opportunity to explore different approaches to the development 

and display of UTM information and to gain insight into 

considerations from the public, industry, and public safety 

organizations on what information should be available regarding 

the operation of UAS in public settings. 

D. CON 4: Multiple Operations for Long Durations 

CON 4 consisted of a long duration scenario in which 

multiple interacting operations were conducted under various 

use cases and missions. The performance of CON 4 served as a 

platform for the demonstration and assessment of the ability to 

safely plan and conduct multiple operations in the same airspace 

with a sustained operational tempo. The duration of each CON 

4 test was intended to last at least two hours. 

E. CON 5: Unauthorized Airspace Entry/Exit 

For the CON 5 tests, operators intentionally flew their 

vehicles out of its Operation Volume and towards controlled or 

otherwise unauthorized airspace in order to evaluate the 

procedures, interactions, and information exchanges needed in 

cases where a vehicle is near or within unauthorized airspace. 

New UTM messages were added to alert operators to their 

proximity to and breach of existing airspace class boundaries as 

well as dynamic and/or static airspace structures currently 

referred to as UAS Volume Reservations. 

III. TEST PERFORMANCE 

The CON tests were assigned to the test sites according to 

a number of considerations. Fig. 1 shows the final distribution 

of tests per site where broad coverage was achieved for each test 

to be performed in at least three instances. The testing window 

for the CON tests opened with CON 5 in North Dakota on March 

22, 2018 and closed on May 25, 2018 in Alaska with CON 5 as 

well. 

Fig. 1. Distribution of CON tests across TCL3 test sites 

Across the five test sites, a total of 16 different types of 

vehicles were flown in support of the CON tests. The 

complement of vehicles consisted of a mix of multi-rotor, fixed 

wing, and hybrid configurations with varying levels of sensor 

equipage and capabilities. The configuration of ground control 

stations for those vehicles, display presentations, and operator 

interactions with the UTM system were not prescribed. Rather, 

the operational test requirements were prescribed (e.g., safe 

flight operations while connected to a USS and exchanging 

data) and the topics of information display and operator 

interactions were approached as research areas that were 

addressed by the human factors team out in the field. Refer to 

[8] for their overall TCL3 report. 

TCL3 testing further incorporated the UTM architecture 

built upon the previous tests in TCL1 and TCL2 and initially 

defined in the concept of operations [1]. Seven distinct UAS 

Service Suppliers (USS) supported operations that participated 

in the CON tests. Each USS was connected to the USS Data 

Collector (UDC), which recorded all of the UTM data shared 

by each USS regarding operations, positions, messages, and 

airspace constraints. These data were also complemented by 

data received post-flight through the established data 

management plan, which consisted of, for example, data direct 

from the vehicles, architectural and process/procedural 

definitions, and off-nominal reports. Additionally, subjective 

data and observations were collected at each of the test sites by 

human factors researchers related to operator interactions and 

approaches to UTM integration as well as feedback on areas of 

the UTM concept as experienced through the tests. 

Following the conclusion of the testing, an effort was 

undertaken to verify the data and arrive at a final set of 

operations and associated elements to use as a reference in 

performing subsequent analyses. The following results are 

based on the outcome of that effort complemented by debrief 

transcriptions, human factors results, and the final reports 

provided by each of the test sites. 

IV. RESULTS 

A. CON 1: Beyond Visual Line-of-Sight Landing 

For the CON 1 tests, the objective was to conduct operations 

in which the vehicle flew beyond visual line-of-sight (BVLOS) 

from the pilot in command, landed at least once while BVLOS, 

and returned to launch point. Throughout the entire operation, 

the vehicle was connected to a USS, which provided strategic 

deconfliction prior to flight and conformance monitoring 

primarily while in flight. 

Three test sites performed CON 1, each with different 

environments and range capabilities. One of the participating 

test sites, for example, operated from an airport. At this site, the 

vehicle was remotely launched from inside a hangar. While 

inside the hangar, the vehicle used positioning data from optical 

flow sensors for navigation while in transit and transitioned to 

GPS once outside. The other sites used open fields and farmland 

within the confines of the test range for their missions. 

Fig. 2 provides a representative example of a CON 1 mission 

reconstructed from position data sent to the vehicle’s supporting 

USS. In this example, the vehicle was launched from a hillside 

parking lot then proceeded to transit out into an open field before 

making a sharp turn to head toward a small forest down range 

that was BVLOS from the pilot. The vehicle overflew an 

outcropping of the forest and performed its landing behind the 

trees before returning to launch. In the provided example, the 

vehicle flew a total enroute distance of 5,888 ft with the landing 

point located 2,654 ft from the launch point. Fig.3 provides 

another example of a long distance BVLOS flight conducted 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

over farmland. In this example, rather than landing, the vehicles 

performed package deliveries at pre-defined drop points at the 

furthest extents of the route. The accuracy of delivery drops 

were assessed in lieu of landing accuracy as done at the other 

test sites. The flight represented in Fig. 3 involved a total enroute 

distance flown of 12,059 ft with a maximum distance from the 

launch point of 5,943 feet. 

Fig. 2. BVLOS landing behind trees at a distance of 2,654 ft from launch point 

Fig. 3. BVLOS package delivery at a distance of 5,943 ft from launch point 

Conducting BVLOS landings and package deliveries 

highlighted the importance of continuous and reliable telemetry 

data as well as the benefits of redundancies in Command and 

Control (C2) and navigation systems. Connectivity to a 

supporting USS throughout BVLOS operations was maintained 

across CON 1 operations, which was critical for the shared 

awareness of those operations within the UTM environment. 

Landings and deliveries were measure for their accuracy for 

select flights within the CON 1 test. For landings, there was a 

range of accuracies from 6 inches to 30 inches offset from the 

target point with issues impacting navigation accuracy theorized 

as the contributor to the variability. The accuracy of package 

deliveries were assessed by examining the location of individual 

packages relative to a circular drop zone with a 5 ft radius. All 

packages were successfully delivered within the defined zone. 

B. CON 2: Contingency Management 

The CON 2 test was designed to exercise the procedures and 

information exchanges involved in managing contingency 

situations while conducting operations as part of UTM. The 

impetus for this test in further developing the concept was the 

need for alerting airspace users via the UTM architecture of 

emergency situations and intent information so that others are 

aware of the situation and have the opportunity to react 

accordingly. To enable this capability, a number of additions 

were made to the UTM API to support the initial approach to 

contingency management within UTM. 

At the planning stages, new fields in the Operation model 

allowed operators to include, as part of their operation 

submission, contingency plan information as pre-defined 

options to invoke while in flight. Items within the contingency 

plan included additional information such as the contingency 

cause (e.g., loss of C2, security incident, or conflict situation), 

contingency response (e.g., loiter or return to base), and related 

location information such as contingency point with associated 

position and relevant altitudes of loiter points. Contingency 

volumes, similar to operation volumes, were also definable and 

meant to be updated in real time in order to provide the operator 

with the ability to quickly update their volume to accommodate 

a contingency situation while maintaining conformance and 

communicating situation and intent to other airspace users. 

Multiple instances of contingency plan information were able to 

be defined and associated with each operation volume segment 

in order to provide adequate coverage for contingencies 

throughout the planned mission. 

As part of the CON 2 tests, the participating test sites 

developed scenarios in which a simulated emergency or distress 

situation was injected as a test event. In response to the event, 

the vehicle operator was expected to communicate the initiation 

of a given contingency plan to the supporting USS, which would 

subsequently be communicated to other operations supported by 

that USS and other USSs as well if present. The contingency 

situations and test responses varied across the test sites, which 

provided an opportunity for broader concept exploration. Fig. 4, 

for example, presents a scripted situation in which an 

unexpected low battery state was detected for a vehicle while 

conducting animal survey and population count type operations. 

In response to the battery state, the contingency response was to 

perform an immediate landing aided by the deployment of a 

parachute on the vehicle. Fig. 4 shows one of the actual 

parachute deployments that occurred as part of CON 2 on the 

left panel, and the associated data from that event on the right. 

The flight profile of the operation is presented on the right panel 

of Fig. 4 where the point at which the parachute was deployed 

can be seen along with the subsequent landing trajectory. Note 

that the operation volume for that operation is rendered in the 

background to show that this contingency event was handled 

within its defined volume and remained within conformance. 

Fig. 5 presents CON 2 as performed at another participating 

test site where a different focus was placed on the types of 

situations that could play a role in contingency management 

within UTM. These sets of tests involved two vehicles in which 

one was performing nominal operations as part of UTM through 

the support of its USS. The other involved vehicle played the 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

role of intruder whereby there was no connection to a USS and 

the airspace was accessed without going through the steps of 

strategic deconfliction and communication with the UTM 

network. However, the telemetry data of the intruder vehicle was 

captured in real time and treated as sensor data for the detection 

of the vehicle locally and visualization of the operation remotely 

mediated by ingestion of that data through UTM endpoints. Fig. 

5 presents a variety of information that capture the breadth of 

what was covered in the CON 2 approach just described. The 

participating UTM vehicle is shown within the bounds of its 

operation volume (the orange box) reporting positions that are 

displayed as white dots. A yellow dot is visible to the right of 

the vehicle, which represented the current reported position of 

the intruder vehicle. The blue message box in the upper portion 

of Fig. 5 shows that the “contingency_plan_initiated” message 

was sent and received by the USS and available for other UTM 

participants to see. 

Fig. 4. Parachute deployment as part of contingency response (left) and 

associated flight profile and operation volume data (right) 

Fig. 5. Cooperative UTM operation in the presence of an intruder aircraft that 

resulted in the initiation of contingency plan 

Feedback from test participants during debrief discussions 

and through survey responses provided insight into the issues 

and considerations as experienced through participation in 

CON 2. At a high level, it was agreed that alerting is an 

important function during a contingency event. However, the 

required reliability, accuracy, and latency of alerting to 

conflicts and contingencies needs continued evaluation. For 

manually controlled operations, the approach to contingency 

management reflected in CON 2 might be difficult to 

implement and use due to ensuring safety of flight before 

interacting with the UTM system and pre-planning 

contingencies. Also, each contingency situation is unique, 

which may not lend itself to taking advantage of the approach 

taken for pre-planned responses. However, for the purposes of 

autonomous flights, contingency management as performed in 

CON 2 might be an appropriate approach for publishing intent 

to the UTM environment. With regard to what information is 

needed for actionable situation awareness by other airspace 

participants, it was reported that desired information consisted 

of the position of vehicle in distress, its altitude, heading, 

velocity, flight trend, position history, aircraft type, and 

distance from ownship. The nature of the emergency that 

necessitated the contingency response was considered 

unnecessary. It was also reported that as with any type of 

alerting, the frequency, saliency, and validity of alerts all 

impact the effectiveness. 

C. CON 3: UTM Public Portal 

CON 3 involved the design and development of an 

application intended to provide public users access to UTM 

information. One of the main objectives of the test was to 

understand the needs and concerns of the general public as well 

as public safety and other stakeholders with regard to UAS 

operations and how a platform such as the Public Portal could 

be designed to address those concerns. 

Four of the test sites participated in CON 3. A total of five 

Public Portal prototypes were developed by industry partners 

across the test sites, each with their own unique designs and 

approaches. An additional portal was developed internally at 

NASA Ames that leveraged existing interfaces and tailored for 

CON 3. Fig. 6 presents a collection of screenshots from the 

interfaces that were developed where it can be seen that there 

was variability in the design approaches. 

Fig. 6. UTM Public Portals developed by Industry partners and NASA to support 

CON 3 

The design requirements were not prescribed to the 

participating partners. The intent, rather, was to allow the 

partners freedom to approach the development independently. 

While all of the portals included a base version intended for 

general use, three of the interfaces included a public safety 

version for testing with relevant personnel. As the CON 3 

window opened, a reference guide was sent to all of the 

participants that detailed the expectations and required 

deliverables in terms of reporting and testing with users. As each 

of the Public Portals were complete, participants were brought 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

in to take part in usability tests and discussions. For the usability 

tests, a number of simple tasks were administered that were 

designed to exercise different functionalities of the portal and 

present opportunities for the user to think about what types of 

information are important for them given their background and 

perspectives. 

With respect to usability, a total of 16 participants completed 

the tests and associated survey. General satisfaction of the 

portals was rated fairly high across portals with average ratings 

on a 7-point scale (with 7 representing ‘Very Satisfied’) ranging 

from 4.67 to 5.75. Some common feedback that likely impacted 

satisfaction and usability ratings were related to difficulties in 

information access and issues with responsiveness and lag 

experienced with the interface. 

In addition to usability aspects of the Public Portal, 

participants were also asked questions that were more 

fundamental to the UTM concept related to transparency and 

accessibility of information. Through the responses of the 

participants, an overarching theme emerged: desire for knowing 

more about the flight’s purpose and the operator. For example, 

in response to the question, “What types of information do you 

think would be most valuable?,” one response was: 

- Ownership, make, model 

- Who, what, where, why 

- Payload type (is a camera on board) 

- Type of operations (individual/hobby or commercial) 

- IFR/flight plan (if applicable) 

The provided response was frequently echoed in various 

forms across the participating test sites. It should be noted, 

however, that there were concerns by some participants 

regarding the sharing of certain data related to identity and 

contact information. However, there was general agreement that 

there should be different levels of information access depending 

on the user’s role or position. For example, an indicative 

response to the question, “What data should be available for 

Public vs Public Safety?,” was: “GCS location, Contact 

Information on Public Safety Portal and not on general public 

portal (analogy to license plates).” There was also a pattern of 

opinion that information should not be publicly available that 

could impact general safety or missions in support of public 

safety. 

In parallel with the CON 3 tests, an effort was also initiated 

at NASA Ames Research Center to engage with the general 

public, government, industry, and public safety entities 

regarding UTM and the areas addressed in CON 3. A number of 

focus group sessions were held for demonstrations as well as 

discussions on topics relevant for the group demographics. A 

total of 31 individuals participated in these discussions and the 

outcomes of those focus group sessions can be found in [9]. 

Usability tests more directly in line with CON 3 were also 

conducted using a Public Portal that was developed within the 

Airspace Operations Laboratory. Eleven individuals 

participated in these local CON 3 studies and the results will be 

included in a forthcoming publication. Fig. 7 provides examples 

of participants in the laboratory studies. The findings of that 

study were in general alignment with what was observed more 

broadly in CON 3. 

Fig. 7. Participants of the CON 3 Public Portal studies at NASA Ames Research 

Center 

D. CON 4: Multiple Operations for Long Durations 

In the TCL3 demonstration, tests were designed to more 

specifically address a particular research area within UTM. 

CON 4 was unique among the tests as it more broadly sought to 

assess the abilities of operators to perform a variety of 

interactive operations that, at a higher level, provided an 

opportunity to observe the performance and capabilities 

involved in achieving and sustaining an operational tempo over 

longer durations of time. While most tests in TCL3 did not last 

much longer than the battery life of individual vehicles, CON 4 

had a minimum duration of two hours with longer times 

encouraged. 

Due to the longer duration of these tests and the intended 

interactions between operations, there was an opportunity to 

perform other tests in conjunction with CON 4. Many of the 

other CON tests were performed within the CON 4 umbrella as 

well as others from the data exchange tests such as USS Failover 

and USS-to-USS Negotiations. Conflict situations and 

contingency events were also incorporated in CON 4 tests across 

the test sites. The types of missions flown varied and included 

package deliveries, surveys, search and rescue, photogrammetry 

missions, surveillance and mapping, precision agriculture, and 

animal counts. CON 4 was conducted at four test sites over a 

combined seven days of testing. 

Each of the test sites took a different approach and focus in 

their performance of CON 4. One representative example can be 

seen in Figs. 8 and 9, which represents a day in which there were 

more than 3 hours of operations with 80 flights that performed 

different missions in a complex operational environment. One 

of the key elements in this example was the management of 

airspace and the ability to provide strategic deconfliction for 

multiple operations across multiple USS through data 

exchanges. Fig. 8 presents the full complement of operations and 

their volumes that were successfully deconflicted between two 

USSs. The colors of the volumes shown in Fig. 8 map to the USS 

that supported the operations such that blue volumes represent 

operations supported by one of the USS and the purple volumes 

map to the other. From this figure, it can be seen that there were 

many interacting operations involving different flight profiles 

and mission types that required well-defined procedures for 

ensuring strategic deconfliction between USSs. Fig. 9 presents a 

zoomed in view of what is presented in Fig. 8 that focuses on the 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

operations supported by one USS where the complexity of 

volumes and demand focused in localized airspace was quite 

high. 

Fig. 8. Full set of Operation Volumes supported by two USSs as part of one CON 

4 iteration 

Fig. 9. Zoomed in view of Operation Volumes supported by one USS in CON 4 

Across the test sites and throughout the CON 4 testing 

window, multiple hours of operations were successfully 

performed under a variety of conditions and with the integration 

of a number of targeted tests. The ability for multiple USS to 

provide strategic deconfliction as observed in CON 4 and 

exemplified in Fig. 8 demonstrated the viability of USS to USS 

communications and laid the foundations for achieving high 

density operations envisioned in environments such as those 

described as part of TCL4. In addition to USS to USS 

communications, the application of segmented Operation 

Volumes and ability for altitude stratification was noted to be 

of strong value in reducing congestion and more effectively 

managing the airspace to safely enable higher levels of 

complexity and density. Relatedly, CON 4 also incorporated the 

concept of shared airspace in which multiple vehicles were able 

to enter the same volume of airspace to perform cooperative 

missions. 

E. CON 5: Unauthorized Airspace Entry/Exit 

The CON 5 test assessed the ability for USSs to provide 

alerting to operators regarding their proximity to or position 

within airspace that the operation is not authorized access. This 

test also exercised the functionality for a USS to establish 

airspace structures referred to as UAS Volume Reservations 

(UVR). In CON 5, UVRs were either established prior to 

commencement of a given run to serve as a static structure 

within the airspace, or activated within the testing area while 

operations were already underway. Traditional airspace 

boundaries were also utilized as part of the tests (e.g., Class E 

airspace). Fig. 10 presents a collection of these airspace 

structures that were used as part of CON 5 testing at one of the 

three participating test sites. 

Fig. 10. Collection of airspace structures applied at one test site during CON 5 

testing 

Regardless of the type of airspace structure used, the USS 

functionality developed in support of CON 5 involved a phased 

alerting scheme in which an operator, via the supporting USS, 

first received an airspace proximity warning message when the 

vehicle was within a prescribed distance to the defined airspace. 

As an initial approach, the decision was made to set the distance 

at which the airspace proximity warning message was sent to the 

operator when the vehicle was within 3038 ft (~0.5 nautical 

miles) of the airspace boundary. If a vehicle breached the bounds 

of the unauthorized airspace, an unauthorized airspace entry 

message was sent to the operator, alerting them to the status of 

the operation. Standard conformance monitoring protocols were 

also in place that first alerted the operator to Non-conforming 

and Rogue UTM states when vehicles approached and exceeded 

the outer bounds of its Operation Volume. In certain iterations 

of CON 5, vehicles were intentionally diverted to exit the 

Operation Volume and subsequently approach and enter the 

identified airspace as part of the testing protocol. Fig. 11 

provides an example of the alert messages sent to two operations 

where the yellow dots represent the positions where airspace 

proximity warning messages were sent by the USS to the 

operators, and the red dots represent where the operators were 

sent unauthorized airspace entry messages. 

Fig. 11. Airspace proximity (yellow) and entry messages (red) sent in CON 5 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Although the distance to airspace boundary was prescribed 

with regard to triggering the appropriate alert message to send, 

the frequency at which the messages were sent was not 

prescribed. This was by design and viewed as an open research 

question that CON 5 could provide a window into possible 

answers. Of the USSs involved, two differing approaches were 

taken with respect to the alert messages. One approach was to 

send the proximity or entry message every 30 seconds while the 

triggering conditions still applied. The other approach was to 

only send the relevant message upon a change in status (e.g., 

once when within the proximity distance and once when the 

airspace was breached). Debrief discussions held with 

participants at each of the sites resulted in a general debate as to 

what the most appropriate approach should be to alerting for 

airspace interactions. While there was consensus on the value of 

the alerts, a clear consensus was not reached with regard to the 

timing and parameters set for where and when the alerts are sent. 

There was, however, concern for the danger of over alerting if 

the messages are sent too often. Refer to the CON 5 section of 

[8] for a more in-depth discussion of the issue. 

In addition to the implementation of UVRs and the 

proximity/entry messages discussed thus far, there were 

additional advances that were brought forward to test as part of 

CON 5 by the industry partners. One example can be seen in Fig. 

12 where the concept of dynamic operation updates were 

performed as a means of remaining in conformance. In this case, 

the vehicle was initially nearing the outer bounds of its 

Operation Volume and on trajectory to continue outside, which 

would result in a state transition to Rogue status. To avoid that 

situation, the operation updates were dynamically made to 

contain the vehicle along its trajectory in order to remain in 

conformance and provide some level of intent information to the 

UTM system. The capability to allow selective access for 

priority operations was also successfully demonstrated as part of 

CON 5. 

Fig. 12. Dynamic Operation Volume updates to remain in conformance 

A final example to present for the CON 5 tests can be seen 

in Fig. 13 where a dynamic UVR was established via USS to 

which all affected operations responded to clear the airspace. In 

this example, live flights were initially taking place and 

performing their assigned missions. Simulated operations were 

also injected into the environment from the Airspace Operations 

Laboratory at NASA Ames Research Center. Once all 

operations were fully in progress, a dynamic UVR was 

established in the airspace (denoted by the blue box in Fig. 13). 

Once the UVR was established, the appropriate alert messages 

were sent to all affected operators, which was followed by return 

to launch procedures to clear the UVR of active operations. All 

live and simulated flights were able to successfully return to 

their launch locations and close their UTM operation. This 

particular test iteration demonstrated the integration of live and 

simulated UTM operations, dynamic UVRs and messaging, as 

well as the procedures necessary to respond to such airspace 

structures. 

Fig. 13. Live and simulated operations react to Dynamic UVR (blue box) 

Through debrief discussions following tests that involved 

dynamic UVRs, one issue emerged regarding its implementation 

in CON 5. The approach taken in this testing was for a UVR to 

be active as soon as the message was sent. This meant that all 

operations within the UVR that was just activated were 

immediately sent unauthorized airspace entry messages without 

having time to plan and react. Feedback from participants was 

that there should be some lead time to allow operators to plan an 

appropriate response to clearing the UVR that accounts for the 

various factors that need to be considered such as battery 

remaining or optimal routing. 

SUMMARY 

The UTM TCL3 flight demonstration was conducted in the 

spring of 2018 and focused on targeted tests in the topic areas 

of Data Exchange, Communications and Navigation, Sense and 

Avoid, and Concepts and Use Cases. Under the umbrella of the 

Concepts and Use Cases research thrust, five tests -referred to 

as the CON tests- were developed to exercise the capabilities, 

procedures, and interactions needed for BVLOS landings and 

launches (CON 1), contingency management within the UTM 

construct (CON 2), access to UTM information via a Public 

Portal (CON 3), sustained UTM operations over a prolonged 

period of time (CON 4), and alerting based on proximity and 

breach of unauthorized airspace (CON 5). These tests were 

performed at five different test sites and in different 

combinations, which resulted in a variety of approaches to the 

tests and unique environments in which to conduct them. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Seventeen tests were conducted in total in which multiple 

vehicles and vehicle types were flown in an environment in 

which multiple UAS Service Suppliers were supporting 

operations and providing the basis for information exchanges 

between the UTM system and individual operators. Many 

different types of missions were flown as part of an integrated 

storyline for the tests, each with unique flight profiles and 

associated Operation Volumes. 

Each of the CON tests was successfully completed, which 

provided valuable insight into the underlying concept elements. 

Through the execution of multiple operations that included 

landing and launch phases as well as package deliveries while 

BVLOS, the importance of consistent and dependable 

communications and navigation systems with redundant 

features was made clear in order to ensure operational 

conformance and situation awareness for other airspace users. 

The ability to pre-define and enact contingency management 

procedures with appropriate messaging in response to simulated 

emergency and distress situations through the UTM system was 

also demonstrated. This capability becomes more important as 

operations reach higher densities in more complex environments 

such as those envisioned as part of TCL4. Multiple Public Portal 

prototypes were developed to explore the usability and 

information access considerations from user groups such as the 

general public and public safety entities. Important topics 

emerged regarding the balance between privacy and 

transparency in UTM that will be a continued area of research 

and discussion. Across the participating test sites, multiple 

interacting UTM operations were conducted and sustained over 

long durations. The importance of airspace negotiation and 

efficiency of use were common themes that emerged as a result. 

Finally, the establishment of UVRs with associated operator 

alerting to proximity and entry of the defined airspace was 

successfully integrated and tested. This test provided an 

opportunity to assess the key considerations in the management 

of airspace as part of UTM. 

BEYOND TCL3 

The results and lessons learned from TCL3 provided 

valuable input and laid a strong foundation for the research 

planned beyond TCL3. Following the research path laid out at 

the outset of NASA’s UTM project, TCL4 is the next and final 

TCL to be addressed. TCL4 addresses high density UTM 

operations in a complex urban environment. Elements initially 

addressed in TCL3 will be further examined to understand the 

key considerations related to topic areas such as contingency 

management, USS negotiations, UVRs and priority operations, 

Remote ID, and many more, to understand how the interactions 

and operational environment change as higher densities and 

more complexities are realized. Fig. 14 presents TCL4 

operations as they are being conducted at the Reno, NV test 

range. Testing will also be conducted in Corpus Christi, TX. 

Results from the TCL4 demonstration will be contained in 

forthcoming publications. 

Fig. 14. TCL4 operations conducted in Reno, NV 

ACKNOWLEDGMENT 

The authors would like to thank the many individuals and 

organizations within and outside of NASA that made the TCL3 

flight demonstration possible. Thank you to the Test Site 

Operators and their partners for their tireless efforts in 

progressing UTM. And a final thank you to the FAA for their 

collaboration through the Research Transition Team. 

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