Real-Time System wide Safety Assurance (RSSA)
Liberty University
AVIA 409 - Safety Management Systems
Professor: Andrew Walton
2022
In-time Aviation Safety Management System (IASMS)
Description
As envisioned by the U.S. National Aeronautics and Space Administration (NASA), a real-time
system wide safety assurance (RSSA) is needed to provide a continuum of information, analysis and
assessment that supports awareness and action to mitigate risks to safety. According to a 2018 report by
the U.S. National Academy of Sciences, NASA’s research plans state that development of an RSSA system
for the national airspace system (NAS) will necessitate automating safety assurance of air transportation
system components, integrating component-level systems, and reducing the safety assurance cycle time
until real-time safety assurance is achieved at the system-of-systems level. The safety assurance system
will combine air traffic and onboard aircraft technologies as well as automated data mining capabilities
for continuous safety monitoring and threat prediction.
Background
The RSSA is thought necessary because of the growing traffic in the NAS, which includes the
increasingly autonomous systems that are being developed for aircraft and ground systems, as well as
small unmanned aircraft systems or drones. In its report, the National Academy of Sciences said, “As the
NAS evolves to accommodate these changes, aviation safety programs will also need to evolve to ensure
that changes to the NAS do not inadvertently introduce new risks.”
In-time Aviation Safety Management System (IASMS)
The report stated that RSSA should be approached in terms of an in-time aviation safety
management system (IASMS) “that continuously monitors the national airspace system, assesses the
data that it has collected, and then either recommends or initiates safety assurance actions as
necessary.” Some elements of the system would function in real time, or close to real time, while others
would search for risks by examining trends over a time frame of hours, days or longer.
Decades of continuous efforts to address known hazards in the national airspace system (NAS) and
to respond to issues illuminated by analysis of incidents and accidents have made commercial airlines
the safest mode of transportation. The task of maintaining a high level of safety for commercial airlines
is complicated by the dynamic nature of the NAS. The number of flights by commercial transports is
increasing; air traffic control systems and procedures are being modernized to increase the capacity and
efficiency of the NAS; increasingly autonomous systems are being developed for aircraft and ground
systems, and small aircraft most notably unmanned aircraft systems are becoming much more
prevalent. As the NAS evolves to accommodate these changes, aviation safety programs will also need
to evolve to ensure that changes to the NAS do not inadvertently introduce new risks.
Real-time system-wide safety assurance (RSSA) is one of six focus areas for the National
Aeronautics and Space Administration (NASA) aeronautics program. NASA envisions that an RSSA system
would provide a continuum of information, analysis, and assessment that supports awareness and
action to mitigate risks to safety. Maintaining the safety of the NAS as it evolves will require a wide
range of safety systems and practices, some of which are already in place and many of which need to be
developed. This report identifies challenges to establishing an RSSA system and the high-priority
research that should be implemented by NASA and other interested parties in government, industry,
and academia to expedite development of such a system.
Decades of continuous efforts to address known hazards in the national airspace system (NAS) and
to respond to issues illuminated by analysis of incidents and accidents have made commercial airlines
the safest mode of transportation. The task of maintaining a high level of safety for commercial airlines
is complicated by the dynamic nature of the NAS. The number of flights by commercial transports is
increasing; air traffic control systems and procedures are being modernized to increase the capacity and
efficiency of the NAS; increasingly autonomous systems are being developed for aircraft and ground
systems, and small aircraft most notably unmanned aircraft systems are becoming much more
prevalent. As the NAS evolves to accommodate these changes, aviation safety programs will also need
to evolve to ensure that changes to the NAS do not inadvertently introduce new risks.
Real-time system-wide safety assurance (RSSA) is one of six focus areas for the National
Aeronautics and Space Administration (NASA) aeronautics program. NASA envisions that an RSSA system
would provide a continuum of information, analysis, and assessment that supports awareness and
action to mitigate risks to safety. Maintaining the safety of the NAS as it evolves will require a wide
range of safety systems and practices, some of which are already in place and many of which need to be
developed. This new report, from the National Academies of Sciences, Engineering, and Medicine,
identifies challenges to establishing an RSSA system and the high-priority research that should be
implemented by NASA and other interested parties in government, industry, and academia to expedite
development of such a system.
The National Academies of Sciences, Engineering, and Medicine has released a report that identifies
challenges to establishing a real-time system-wide safety assurance (RSSA) system and the high-priority
research that should be implemented by the National Aeronautics and Space Administration (NASA) and
other interested parties in government, industry, and academia to expedite development of such a
system. RSSA is one of six focus areas for the NASA aeronautics program. NASA envisions that an RSSA
system would provide a continuum of information, analysis, and assessment that supports awareness
and action to mitigate risks to safety. Maintaining the safety of the NAS as it evolves will require a wide
range of safety systems and practices, some of which are already in place and many of which need to be
developed.
Decades of continuous efforts to address known hazards in the national airspace system (NAS) and
to respond to issues illuminated by analysis of incidents and accidents have made commercial airlines
the safest mode of transportation. The task of maintaining a high level of safety for commercial airlines
is complicated by the dynamic nature of the NAS. The number of flights by commercial transports is
increasing; air traffic control systems and procedures are being modernized to increase the capacity and
efficiency of the NAS; increasingly autonomous systems are being developed for aircraft and ground
systems, and small aircraft most notably unmanned aircraft systems are becoming much more
prevalent. As the NAS evolves to accommodate these changes, aviation safety programs will also need
to evolve to ensure that changes to the NAS do not inadvertently introduce new risks.
In-Time System-Wide Safety Assurance (ISSA) Concept of Operations
Emerging operations involving Urban Air Mobility (UAM) poses a challenge to safety assurance and
accessibility to the NAS. In particular, the public has a low tolerance for risk in aviation and the current
NAS tends to be labor-intensive with limited ability to scale up for UAM. In response to this landscape,
NASA is collaborating with industry to define an In-time Aviation Safety Management System (IASMS)
Concept of Operations (ConOps) for a scalable UAM along with a service-oriented architecture. This
architecture would better focus safety investments for technological solutions that overcome safety
related barriers for emerging operations. By working with industry, consensus can be reached on
desirable system traits that are based on integration of data and leverage increasingly autonomous and
automated systems. These complex systems can identify anomalies, precursors, and trends that
together enable more proactive management of operational risks.
Need for ISSA
Maintaining the safety of the NAS as it evolves will require integration of a wide range of safety
systems and practices, some of which are already in place and many of which need to be developed.
Maintaining system safety into the future will require rapid detection and timely mitigation of safety
issues as they emerge and before they become hazards. -(NAR pg 2)As part of its Aeronautics program,
NASA is pursuing and progressing new concepts and technologies in its strategic implementation plan
under Thrust 5, In-Time System-Wide Safety Assurance (NASA, 2017). A key element of this work
involved a NASA request to the National Academies to review the current state, policy, and technology
for aviation safety management. NASA currently has three high-level milestones for technology
advancement:1.Domain-Specific Safety Monitoring and Alerting Tools2.Integrated Predictive
Technologies with Domain-Level Application3.Adaptive real-Time Safety Threat ManagementNASA in
developing the ISSA CONOPS is defining the scope, functionality, and technical challenges required for
an integrated IASMS. The ISSA CONOPS is framed by the safety services essential to system safety,
exemplified via effective use cases with reference to the UAM CONOPS, the FAA UTM CONOPS, and the
National Academies report on the IASMS asthreads to ensure a full scope of necessary capabilities. For
the purposes of this ISSA CONOPS, IASMS capabilities are defined as operational systems with functional
elements that provide monitor, assess, and mitigate services to provide safety assurance of operations
in the NAS. IASMS capabilities address the need to provide risk management and safety assurance to the
NAS. Timely feedback from stakeholders on this initial approach to the CONOPS is an important check to
ensure the right capabilities and challenges have been identified as foundational to further development
of the CONOPS. This includes participation from UAS operators, commercial industry, airports, FAA, and
others. NASA will survey stakeholders during the August Autonomy Workshop and solicit operational
recommendations.The scope of the ISSA ConOps and relative reference to other facets of air
transportation safety is framed by the ICAO definition of the overall Safety Management System (SMS),
as shown in Figure 1. This figure shows the relationships of IASMS and ISSA within the SMS as a whole.
In-Time Aviation Safety Management Systems
The concept of real-time system-wide safety assurance should be approached in terms of an in-
time aviation safety management system (IASMS) that continuously monitors the national airspace
system, assesses the data that it has collected, and then either recommends or initiates safety assurance
actions as necessary. Some elements of such a system would function in real time or close to real time,
while other elements would search for risks by examining trends over a time frame of hours, days, or
even longer.-(NAR pg 3)
Vision of an In-time Aviation Safety Management System1.An IASMS will continuously monitor the
NAS or sub-element(s) within the NAS to collect data on the status of aircraft, air traffic management
(ATM) systems, airports, weather, and so on,and then assess that data, as follows:
a. Assess data on a second-by-second, minute-by-minute, and hour-by-hour basis to detect or
predict elevated risk states based on rapid changes in system status. (Different elements of a safety
assurance system will operate on different time scales.) Data of interest include the status and
performance of vehicle systems, ground systems, operators, and weather. However, the system would
not be designed to predict or respond to emergencies caused by catastrophic equipment failures, such
as an uncontained engine failure or a landing gear collapse.
b. Assess data over periods of days to detect risks based on longer-term trends.
c.
Detect and predict elevated risk states that arise from a confluence of factors, none of which by
itself would be noteworthy.
d. Assess data in the context of a thorough understanding of (1) the nominal performance of
systems and operators, (2) historical data regarding both the occurrence and consequences of off-
nominal situations, and (3) the fault tolerance of the NAS and its key elements.
e. Assess system outputs over long periods of time to identify emergent risks that in some cases
should be added to the list of risks that the system is designed to monitor.2.An IASMS will be focused on
risks that require safety assurance action in-flight or prior to flight. Preflight safety assurance action may
include a decision to postpone or cancel a flight until, for example, flight conditions change or
equipment is repaired.
An IASMS will not be designed to recommend safety assurance actions that would occur over a
period of weeks, months, or longer, such as changes to pilot training programs, operational procedures,
equipment design, or the content of scheduled maintenance checks. The output of an IASMS, however,
may be useful to those who are responsible for these longer-term areas of interest.3.Safety assurance
actions generated by an IASMS may take the form of recommendations that operators take action. In
some cases when urgent action is required, IASMS may be designed to initiate safety assurance actions
on their own.
Scope of ISSA ConOps
The ISSA ConOps exists to describe how the future ISSA system will operate on a functional level
and will define the issues that an IASMS will address. The ISSA ConOps will identify the key technical and
policy issues that may impact the industry’s ability to develop and integrate IASMSs in the existing NAS
andits operational sub-elements. Most importantly, the primary intent of the ISSA ConOps is to manage
the cost/complexity of IASMSs, primarily through prioritization of risks requiring mitigation. This
requires an evaluation of the risks that are
a.) most likely to occur and
b.) have the most severe consequences in an evolving NAS that incorporates new entrants. The
scope of this ISSA ConOps includes consideration of aircraft types, including new entrants across aviation
domains (i.e. traditional scheduled operations, small UAS, etc).
Across aircraft type and operational domains, the ISSA ConOps considers the data requirements
necessary to enable an effective prototypical IASMS, and to identify known and emergent risks. Other
considerations include cross-references to other ConOps: including the UTM ConOps (published
reference) and the UAM ConOps (currently in development) to incorporate future operations in
different classes of airspace. The ISSA ConOps will define the relevant time scales for each
functionalelement of the proposed general system model (monitor, assess, and mitigate). The time scale
considerations will be determined based on the critical safety risk mitigation requirements to ensure
equivalent or improved safety of the overall NAS and the elements operating within it. Finally, the ISSA
ConOps must consider scalability of the proposed systems. This means that the ConOps must be
iterative in nature so that future adaptations may be made as technology advances to solve increasingly
complex system challenges. Scalability includes not only expanding the data and systems architecture to
account for additional safety services but also more complex designs as highlighted with additional use
cases involving those safety services.
The ConOps takes further consideration of the following:
●Ability to collect, share, protect, manage, and assure the quality of required data
●Architecture and NAS evolution
●Effectiveness comparing costs and benefits
●Human performance limitations and human-machine roles
●System authority vis-a-vis human performance capabilities and limitations
●Interoperability with legacy ATM systems and procedures
References
In-Time Aviation Safety Management: Challenges and Research for an Evolving Aviation System.
National Academies of Sciences, Engineering, and Medicine 2018. Washington, DC: The National
Academies Press.
