Importance of Time Synchronization and Signal Filtering in Automated Flight Inspection Systems
Aleksander Hagen, Geir Bergsløkken and Erling Grønbeck, Norwegian Special Mission AS, Norway
Location: Regency Ballroom
Date/Time: Monday, Apr. 16, 5:00 p.m.
By the introduction of automated flight inspection systems and computerized data management systems, the efficiency of flight inspection missions has increased in terms of the number of calculating operations which can be performed in parallel. The automated flight inspection systems have contributed to more cost-efficient operations for the operator organizations, as well as a better working environment for the flight inspectors.
Over years, lots of efforts have been invested by FAA, ICAO and national authorities in defining unified procedures and tolerances on how to perform flight inspection. However, when it comes to how flight inspection systems shall be designed to process inputs and provide trustworthy outputs, there are no specific rules or regulations on a corresponding level. This leaves the manufacturer of the flight inspection systems with the sole responsibility to ensure that the data coming out from their systems is correct.
With a flight inspection system incapable of handling time-synchronization of streaming data, including delays and distortions that will always affect a signal stream during the processing, results cannot be guaranteed to be correct. It is therefore a critical aspect of any automated flight inspection system that for all signals being processed by the system, these factors must be known, controlled and corrected for.
Also to consider is the individual characteristics of avionic sensors and subsystems being used to provide input data to the automated flight inspection sensors. These are ranging from traditional analogue to new generation digital electronic units with a great variation of physical interfaces and internal processors, in turn resulting in varying characteristics of signals entering the flight inspection system. This means that a fully automated flight inspection system must be able not only to read signals straight from standard avionic sensors, but it must also have the capability to apply filters as required to extract correct signal properties.
This paper presents practices and examples of how this can be managed and implemented, as well as showing examples and cases demonstrating consequences of lack of proper implementation.