Aircraft Landing Gear Uplock System with Dual Sensor Detection
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Solution Overview
Problem
Existing aircraft uplock systems fail to detect structural failures that can result in a hidden mode where the landing gear appears locked but is not securely retained, as the locking lever remains in the locked position even when the hook has dropped, leading to potential safety issues.
Innovation Solution
An uplock system with a proximity detector and a signal processing unit that combines inputs from the uplock hook sensor and proximity detector to confirm both the hook's closed position and the capture pin's captured position, providing a reliable assessment of the landing gear's secure retention, and alerting the pilot to any faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single sensor is used to detect the hook's closed position, then the device complexity is reduced, but the reliability of detecting both hook position and capture pin engagement is insufficient
Solution Approach 1:
The detection system is divided into two separate sensors: a first sensor that detects the hook's closed position and a second sensor that detects the capture pin's engaged position. This segmentation allows each sensor to independently verify a specific condition, ensuring that both the hook and capture pin are properly positioned before confirming the landing gear is locked, thereby improving detection reliability without excessive complexity.
2Reliability
If the locking lever remains in the locked position after hook failure, then the mechanical locking function is maintained, but the ability to detect actual secure retention is lost
Solution Approach 1:
The system incorporates direct feedback from two sensors that continuously monitor the actual physical positions of the hook and capture pin. This feedback mechanism provides real-time information about the true state of the locking system, allowing the control system to detect when the hook or capture pin fails to engage properly, even if the locking lever remains in the locked position due to mechanical coupling.
3Measurement precision
If only the hook position is monitored, then the measurement system is simpler, but the precision of assessing secure retention is insufficient
Solution Approach 1:
The monitoring system is segmented into two independent detection functions: one sensor dedicated to monitoring the hook's closed position and another sensor dedicated to monitoring the capture pin's engaged position. This segmentation enables precise measurement of each critical parameter separately, ensuring that the system can accurately determine whether both conditions are met for secure retention, thereby improving measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures that the aircraft landing gear can be reliably confirmed in the 'UP and LOCKED' condition, preventing hidden failure modes and enhancing safety by providing a clear indication of the landing gear's secure retention status.
Implementation Method 1
a proximity detector arranged to detect, preferably directly detect, when the landing gear is up
Data Source
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AI summary
An uplock (101) for use with an aircraft landing gear (125) comprises a hook (102) configured to engage a capture pin (126) mounted on the landing gear. The hook (102) is mounted for movement between a closed and locked position and an open and unlocked position. A proximity detector (152, 154) directly detects whether the pin (126) is "up". An uplock hook sensor (114) detects when the hook (102) is in the closed and locked position. The outputs of the proximity detector and the uplock hook sensor may be used to indicate the "up and locked" condition (e.g. if both the capture pin is in its captured positon - i.e. landing gear up - and the hook is in its closed/locked position) and / or to indicate a fault (e.g. in the event that the hook is in its closed/locked position, but the capture pin is not in its captured positon). Such outputs may be provided by an associated device (146) of an avionics system.