Onboard Active Safety System
Due to the growth of complexity and cost of aviation operations caused by the increase in the number of aircraft and air traffic, it has become clear that in the not too distant future it will be impossible to provide and maintain appropriate levels of flight safety with the current safety systems and aviation infrastructure. The aim of the ONBASS project, therefore, is to propose, analyse and develop the innovative Principle for Active System Safety (PASS) for aviation.
Rather than just recording data during an aircraft's flight, in order to allow post-crash analysis to be carried out, ONBASS proposed the analysis of available data in real time during the flight and reacting on them with the aim of accident prevention.
ONBASS was concerned with the formulation of the theoretical principles of aviation system safety: the flight safety (risk) model, the information flow model and the control system model. These models make it possible to determine the scope of the applicability of ONBASS.
Subsequently, analysis of the dependencies within and between the models will permit the definition of the features, functions and structures of the system, software and hardware. The project involved drawing up a comparison between the existing and the proposed system structure of aviation safety, with the aim of optimising the project's outcomes.
To match this demand, the scope of ONBASS was the following:
- Further theoretical and conceptual development of the active safety principle and formation of theoretical models to analyse the limits of the principle's applicability;
- Research and development of basic fault tolerant hardware elements for the on-board part of the active safety system;
- Concepts, design and development of a resilient system software core for the active safety system.
In terms of the system software, the main characteristics of ONBASS were extremely high reliability, fault-tolerant concurrency, recoverability of processed data, support mechanisms for real-time fault detection, system reconfiguration in case of hardware fault or degradation, high performance and hard real-time scheduling. In terms of system hardware, ONBASS aimed to provide the highest possible reliability, recoverability, fault tolerance, thermal and vibration resistance, survivability and graceful mechanical degradation.
The initial phase of the project covered the theory and operational model, taking into account the intended application domain of general aviation. After a systematic survey of the application domain and the processing of existing statistical data within it, the profile of flight risk for commercial and general aviation was developed. With this data available, in combination with the analysis of existing systems, a conclusion is made about features of operational models that will enable an operational risk analysis in flight real-time. From the operational risk analysis model, a reliability model of flight is derived, aiming at the possibility of real-time prognosis of flight risk. The programming of the reliability model and a simulation of its operation in real-time data processing is carried out.
Based on this, the overall system is defined and specified. The objectives of this work are to clearly and concisely define the overall requirements of the system, both from the external point of view of its users and also in terms of its internal function, and to ensure that the safety context and safety requirements are clearly defined. The outcome of this work is a system specification covering software, hardware and overall system aspects, which include safety, certification and qualification and human-machine interface issues.
After this step, the software and hardware modules of the demonstrator are developed in parallel. This work begins with a definition of the respective software and hardware structures, and is completed with the verification of the software modules and the hardware prototype. The main objective of the hardware-related work consists of developing a highly reliable system including fault-tolerant processors, system memory, flight memory and communication interfaces.
Finally, the verified software modules are integrated into the corresponding hardware prototype and an overall system verification is performed, making use of suitable simulation and laboratory set-ups. Following verification of the overall system performance, the ONBASS prototype is installed on-board a general aviation aircraft in order to verify the system in flight. However, the flight hours are limited. This means that validation activities onboard the aircraft are outside the scope of this project.
The ONBASS system, by design, possesses a number of innovative features as far as its operational characteristics. These innovative features offer the users of the ONBASS system a series of benefits of which the most predominant are described in following:
- Real-time active safety - will greatly assist in reducing the number of general aviation (as the primary field of application) accidents and resulting casualties.
- Fault-tolerant ONBASS system processor and RAM - will result in extremely high reliability and availability of the system and very rare on-site maintenance actions.
- Fault-tolerant ONBASS flight data memory - will result in a high integrity and trustworthiness of the stored data.
- Resilient ONBASS software core - will greatly contribute in the extremely high reliability and availability of the system, as well as in the uninterrupted and efficient provision of the system's services.
- Independent power supply - will ensure that recording of crucial aircraft parameters continues even prior to / during a hazardous situation / accident or even in the event of the loss of aircraft power.
The initial target market for the ONBASS system will obviously have to be European GA aircraft. This is only reasonable as the geographic distribution and business 'reach' of the ONBASS partners mostly covers this continent. Further, setting-up distribution channels and building on the business contacts and partnerships of the partners would make potential sales in this region much more likely and straight-forward.