Aircraft Landing Gear Brake Cross-Connection Testing via Tachometer Signals
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Solution Overview
Problem
Conventional methods for testing aircraft landing gear for cross-connections between braking systems require raising the landing gear, the use of drills to spin wheels, and three operators, making them inefficient and operator-intensive.
Innovation Solution
A method using tachometers to generate test signals without wheel rotation, allowing for the issuance and monitoring of braking commands to detect cross-connections between braking systems, reducing the need for physical wheel spinning and operators, and utilizing a braking control and monitoring system to automate the testing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional method of spinning wheels with drills is used to test for cross-connections, then the braking system can be tested, but the landing gear must be raised and three operators are required
Solution Approach 1:
The patent extracts the wheel spinning function from the physical wheel itself and transfers it to the tachometer component. By spinning only the tachometer rotor (which is decoupled from the wheel) to generate test signals, the complex procedure of raising the gear and using drills to spin entire wheels is eliminated, while still achieving cross-connection detection
Solution Approach 2:
The tachometer rotor serves as an intermediary element between the test operator and the braking system. By rotating the detached tachometer rotor to generate test signals, the system can simulate wheel rotation without actually rotating the wheel, thereby avoiding the need for complex external spinning equipment
2Reliability
If the conventional method using drills to spin wheels is used, then braking system testing is possible, but the number of operators required increases to three
Solution Approach 1:
The tachometer system performs self-testing by generating its own test signals through rotation of its rotor. The braking system responds to these self-generated signals, and the system monitors its own response, eliminating the need for multiple operators to manually spin wheels and coordinate testing
3Productivity
If the landing gear is raised to enable wheel spinning, then the wheels can be rotated for testing, but the testing procedure becomes more complex and time-consuming
Solution Approach 1:
The patent extracts the tachometer rotor from the wheel assembly and enables it to be spun independently. This allows test signals to be generated without raising the landing gear or rotating the actual wheels, thereby eliminating the time loss associated with gear positioning while maintaining testing capability
Data Source
AI summary
A method of testing an aircraft landing gear is disclosed including: a) generating a test signal with the first tachometer, wherein the first wheel is not rotating during the generation of the test signal; b) receiving the test signal via one of the tachometer output lines; c) issuing a braking command in response to the receipt of the test signal, wherein the braking command is issued via the braking command line which is associated with the one of the tachometer output lines; and d) monitoring a response of the first or second braking system to the braking command to test for a cross-connection between the first and second braking systems. The landing gear includes first and second wheels; a first braking system having a first tachometer mounted to the first wheel and configured to generate a first tachometer signal indicating rotation of the first wheel, and a first brake configured to brake the first wheel.