An Assessment of STPA as Applied to the Scaled Flight Demonstrator Test Program
An Assessment of STPA as Applied to the Scaled Flight Demonstrator Test Program
Date
2024
Authors
MacCafferty, J.P.
Bumgardner, W.R.
Journal Title
Journal ISSN
Volume Title
Publisher
SFTE
Abstract
Systems Theoretic Process Analysis (STPA) is a methodology for system development and safety
assessment which builds on the System-Theoretic Accident Model and Processes (STAMP) causality model
which approaches safety as a dynamic control problem. The STPA methodology addresses system analysis
and safety assessment for systems that involve complex human interactions and high degrees of coupling.
The purpose of this paper is to demonstrate the application of STPA to the remotely piloted Scaled Flight
Demonstrator (SFD) aircraft test program, and assess the effectiveness for test planning and risk assessment
relative to the traditional Test Hazards Analysis (THA) process. The SFD aircraft is a 1:8.5 scaled model of the
Airbus A320 which has been modified into a distributed electric propulsion (DEP) configuration. The aircraft
was developed in collaboration with members of the Clean Sky 2 program: The Royal Netherlands Aerospace
Centre (NLR), Technische Universiteit Delft (TU Delft), The Office national d'études et de recherches
aérospatiales (ONERA), Centro Italiano Ricerche Aerospaziali (CIRA), Airbus, and Orange Aerospace. This
effort identifies multiple benefits for flight testers when applying STPA to a highly complex system, including:
increased knowledge of the system under test, forced collaboration between the test team and system experts,
and identification of risks and mitigations that may otherwise be missed. The team also identifies some
drawbacks to applying STPA, including: the time investment required to learn and apply the process, and the
challenge in identifying specific hardware or software failure modes. Lessons learned and recommendations
are presented to help other flight test professionals determine how and when STPA can best be applied to
their programs in the future.
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Citation
2024 Annual Symposium of the Society of Flight Test Engineers - European Chapter. https://sfte-ec.org/papsimp/2024