Aircraft Flight Management Assembly for FMS Disagreement Validation
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Solution Overview
Problem
Aircraft flight management systems with two FMSs cannot identify which system is defective during disagreements, preventing automatic guidance and RNP AR operations due to the inability to eliminate erroneous computation sources.
Innovation Solution
Implementing a monitoring and backup unit to validate data from the active flight management system and synchronize it with the passive system, using databases of varying integrity levels to ensure valid data usage for computing guidance commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two flight management systems are used for redundancy, then system reliability is improved, but the ability to identify defective systems during disagreements deteriorates
Solution Approach 1:
A monitoring unit is introduced as an intermediary component that independently receives data from both flight management systems and performs cross-validation. This mediator can identify which system is defective during disagreements by comparing their outputs against validated data, resolving the contradiction by enabling defect detection while maintaining the redundant two-system architecture
Solution Approach 2:
The monitoring unit implements a feedback mechanism where it continuously validates data from both FMS systems, provides status information about system agreement/disagreement, and triggers alerts or switchovers when defects are detected. This feedback loop enables the system to maintain reliability through redundancy while actively detecting and responding to defective systems
2Device complexity
If data from active flight management system is used without validation, then system complexity is reduced, but data accuracy and safety deteriorate
Solution Approach 1:
The monitoring unit performs preliminary validation of data from the active flight management system before it is used for navigation and guidance. By validating data in advance using a more accurate database, the system ensures data accuracy without requiring complex real-time processing, thus maintaining acceptable system complexity while improving safety
Solution Approach 2:
The monitoring unit applies partial validation by focusing on critical parameters and using a more accurate database only when needed for validation purposes, rather than reprocessing all data. This selective approach maintains data accuracy while avoiding excessive complexity in the validation process
Data Source
AI summary
A flight management assembly of an aircraft and method of monitoring the flight management assembly. The assembly includes two flight management systems, and a monitoring and backup unit, each of the flight management systems configured for generating data including a trajectory and a prediction of a parameter of the aircraft, one of the flight management systems being active and the other being passive, the monitoring and backup unit configured for carrying out monitoring of at least one of the items of data generated by the active flight management system in order to verify if the item of data is valid, the flight management assembly carrying out, in case of validation of the monitored item of data, a synchronization of the monitoring and backup unit and of the passive flight management system, with data called synchronization data of the active flight management system, namely a flight plan and/or a flight trajectory.