Aircraft Yoke Interference Detection for Auto Pitch Trim Disconnect
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Solution Overview
Problem
Current aircraft automatic pitch trim systems fail to detect and prevent undesired yoke interference, leading to undesirable pitch changes and aircraft climb due to pilot distraction or incapacitation, which results in an out-of-trim condition.
Innovation Solution
A yoke interference detection system that uses sensors to monitor elevator load, aircraft speed, and initial center-of-gravity data to determine if there is interference, generating a disconnect signal to automatically disengage the automatic pitch trim function when interference is detected, thereby preventing an out-of-trim condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the automatic pitch trim function is left operational without interference detection, then the aircraft trim stability is maintained, but undetected yoke interference causes undesired pitch changes and out-of-trim conditions
Solution Approach 1:
The system performs preliminary detection of yoke interference by monitoring elevator load and comparing it to expected values before undesired pitch changes occur. The processing system continuously calculates expected elevator load based on aircraft state and compares it with actual sensor readings, enabling early detection and disconnection of the APT function before an out-of-trim condition develops.
2Object-affected harmful factors
If yoke interference detection and automatic disengagement is implemented, then undesired pitch changes are prevented, but the system complexity increases
Solution Approach 1:
The system uses feedback by continuously monitoring elevator load through sensors, comparing actual values with expected values calculated from aircraft state parameters, and automatically disconnecting the APT function when a discrepancy indicating yoke interference is detected. This closed-loop feedback mechanism provides reliable interference detection without requiring overly complex system architecture.
3Stability of the object's composition
If the APT function counteracts pilot input without interference detection, then trim stability is maintained, but the aircraft may attain an out-of-trim condition before the monitor trips
Solution Approach 1:
The system performs preliminary detection of yoke interference by monitoring elevator load and comparing it to expected values before undesired pitch changes occur. The processing system continuously calculates expected elevator load based on aircraft state and compares it with actual sensor readings, enabling early detection and disconnection of the APT function before an out-of-trim condition develops.
Solution Approach 2:
The system uses feedback by continuously monitoring elevator load through sensors, comparing actual values with expected values calculated from aircraft state parameters, and automatically disconnecting the APT function when a discrepancy indicating yoke interference is detected. This closed-loop feedback mechanism provides reliable interference detection without overly complex system architecture.
Data Source
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AI summary
A system and method for detecting yoke interference for an aircraft having an auto pitch trim function is provided. The system includes a source of elevator load data, a source of aircraft speed data, and a processing system. The processing system is coupled to receive the elevator load data, the aircraft speed data, and initial condition center-of-gravity (CG) data that is representative of at least an estimated initial position of the CG of the aircraft. The processing system is configured to process at least the speed data and the initial condition CG data to: (i) determine an expected elevator load on the elevator flight control surface, (ii) determine if the expected elevator load exceeds the sensed elevator load by a predetermined magnitude, and (iii) when the expected elevator load exceeds the sensed elevator load by a predetermined magnitude, generate a disconnect signal that will disable the auto pitch trim function.