Thrust reverser activation timing to prevent RevFault grounding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aviation turbine engines are often grounded due to a 'RevFault' error message indicating a thrust reverser malfunction, which is triggered by individual fault messages from multiple components, leading to incorrect assumptions of blockages instead of slowness, preventing deployment or reverse thrust even if the thrust reverser could be used.
Innovation Solution
A method to continue activating and deploying the thrust reverser despite error messages by setting specific activation periods for each component, distinguishing between slow and blocked equipment, allowing deployment and reverse thrust if components activate within predetermined times, and storing individual fault messages for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system generates an error message when a piece of equipment does not activate within a predetermined period, then the system ensures safety by detecting potential blockages, but it causes false alarms when equipment is merely slow rather than blocked, leading to unnecessary grounding of aircraft
Solution Approach 1:
The system dynamically adjusts the evaluation criteria for fault detection. Instead of using a fixed threshold, the control device continues attempting to activate equipment that has not responded within the predetermined period, and only generates a definitive error message if activation fails within a longer maximum period. This dynamic approach allows the system to adapt to varying activation speeds while maintaining safety standards.
Solution Approach 2:
The control device performs preliminary activation attempts before issuing a final error message. When equipment does not activate within the predetermined period, the system continues to attempt activation and monitors whether the equipment eventually activates within the maximum period. This preliminary action distinguishes between temporarily slow equipment and permanently blocked equipment, preventing false alarms.
2Reliability
If the system immediately inhibits reverse thrust when an error message is generated, then the system prevents unsafe operation, but it prevents valid operations when equipment is merely slow and could have completed deployment
Solution Approach 1:
The system implements a dynamic response strategy where the inhibition of reverse thrust is not immediate but delayed until the maximum period expires. During the interval between the predetermined period and the maximum period, the system continues monitoring equipment activation status. This dynamic timing allows the system to maintain safety while avoiding unnecessary operational restrictions.
Solution Approach 2:
The control device continuously monitors the activation status of equipment and provides feedback to determine whether to inhibit reverse thrust. If equipment activates within the maximum period, the system receives positive feedback and allows reverse thrust operation. Only when the maximum period expires without activation does the system receive negative feedback and permanently inhibit reverse thrust, ensuring both safety and operational flexibility.
3Device complexity
If the system treats all fault messages equally and issues a unified error message, then the system simplifies the error handling process, but it loses the ability to distinguish between different types of faults, leading to overly conservative responses
Solution Approach 1:
The system segments fault detection into multiple stages: individual equipment activation status monitoring, intermediate error message generation at the predetermined period, and final error message generation at the maximum period. This segmentation allows the system to track the progression of activation attempts and maintain detailed information about each piece of equipment's status while managing complexity through structured processing.
Solution Approach 2:
The system adds a time dimension to fault handling by implementing two distinct time thresholds (predetermined period and maximum period). This temporal dimensionality allows the system to differentiate between temporary delays and permanent failures, preserving diagnostic information about the duration and progression of activation attempts while maintaining a manageable error handling structure.
Data Source
AI summary
A method of controlling a thrust reverser made up of a plurality of pieces of equipment, wherein, in the event of it being detected that one of the pieces of equipment has not activated by the end of a predetermined activation period, an error message relating to the malfunction of the thrust reverser is generated, and in spite of the error message being generated, activation of the equipment is continued, and if the equipment is finally activated before a predetermined maximum period for deployment of the thrust reverser, then deployment of the thrust reverser is continued and the error message relating to the malfunction of the thrust reverser is withdrawn.