Aircraft Yoke Interference Detection via Elevator Load Mismatch
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Solution Overview
Problem
Current aircraft automatic pitch trim systems fail to detect and prevent undesired yoke interference, leading to unintended aircraft pitch changes and climb due to pilot distraction or incapacitation, resulting in an undesired out-of-trim condition.
Innovation Solution
An aircraft yoke interference detection system that processes elevator load, aircraft speed, and initial center-of-gravity data to determine if the expected elevator load exceeds the sensed load by a predetermined magnitude, generating a disconnect signal to automatically disable the auto pitch trim function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the automatic pitch trim function is enabled to counteract pilot input, then pitch stability is improved, but yoke interference detection capability deteriorates
Solution Approach 1:
The system performs preliminary detection by comparing expected elevator load (calculated from speed and CG) with actual sensed load before an undesired out-of-trim condition develops. This early detection allows the system to identify yoke interference promptly while maintaining pitch stability through automatic trim adjustments.
Solution Approach 2:
The system continuously monitors elevator load and compares it against expected values derived from aircraft speed and center of gravity data. This feedback mechanism enables real-time detection of discrepancies indicating yoke interference, allowing the system to maintain both pitch stability and interference detection capability simultaneously.
2Measurement precision
If the auto pitch trim function operates to maintain trim, then pitch control precision is improved, but undesired pitch changes occur due to undetected yoke interference
Solution Approach 1:
The system calculates expected elevator load based on aircraft speed and center of gravity before interference causes significant pitch deviations. This preliminary calculation establishes a baseline for detecting anomalies, enabling early intervention that maintains pitch control precision while preventing harmful pitch changes.
Solution Approach 2:
The system replaces reliance on mechanical yoke position sensing with an electronic calculation-based approach using aircraft speed and center of gravity data to determine expected elevator load. This substitution enables more accurate and reliable detection of yoke interference, maintaining pitch control precision while preventing undesired pitch changes.
3Reliability
If the system waits for predetermined time limit before tripping APT monitor, then false alarms are reduced, but detection response time increases causing out-of-trim conditions
Solution Approach 1:
The system performs preliminary calculations of expected elevator load using aircraft speed and center of gravity data before comparing with actual load. This preliminary action enables immediate detection of discrepancies without requiring time delays, reducing both false alarms and detection response time simultaneously.
Solution Approach 2:
The system changes the detection parameter from time-based monitoring to load-based comparison. By comparing expected elevator load (derived from speed and CG parameters) with actual sensed load, the system achieves rapid detection response without predetermined time limits while maintaining reliability through multi-parameter validation.
Data Source
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.