Aircraft Center of Gravity Determination Using Landing Gear Load Ratios
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Solution Overview
Problem
Current aircraft weight and balance systems require measuring aircraft weight to determine the center of gravity, which can lead to schedule disruptions due to potential discrepancies between measured and calculated weights, and airlines prefer using FAA-approved assumed weights to avoid delays.
Innovation Solution
A method to determine the aircraft center of gravity independently of weight measurement by comparing load measurements from main and nose landing gear struts, using pressure or deflection measurements, and applying adjustments for strut size differences, allowing for accurate CG determination without calculating the aircraft's weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If aircraft weight is measured using landing gear strut pressure to determine center of gravity, then measurement precision is improved, but reliability deteriorates due to potential discrepancies between measured and calculated weights causing schedule disruptions
Solution Approach 1:
The patent introduces an intermediary calculation method that uses the relationship between nose gear load and main gear load to determine CG position without relying on absolute weight measurements. By using the ratio or difference between nose gear pressure and main gear pressure, the system bypasses the need for accurate total weight measurement while still achieving precise CG determination, thus avoiding schedule disruptions from weight discrepancies
Solution Approach 2:
The patent changes the measurement parameter from absolute weight (which requires accurate total weight measurement) to relative load distribution (using nose gear load as a percentage of main gear load). This parameter transformation allows CG determination to be based on load distribution ratios rather than absolute weights, eliminating the reliability issues associated with weight measurement discrepancies
2Measurement precision
If aircraft weight measurement system is used to determine center of gravity, then measurement precision is improved, but device complexity increases due to additional equipment on landing gear struts
Solution Approach 1:
The patent makes the existing landing gear strut pressure measurement system multi-functional by using it for both weight determination and CG determination. Instead of adding separate measurement equipment, the system utilizes the already-present pressure sensors in a novel way - comparing nose gear pressure to main gear pressure to calculate CG position, thereby achieving dual functionality without increasing device complexity
Solution Approach 2:
The patent extracts the CG determination function from the weight measurement system. By separating the CG calculation from the absolute weight measurement requirement, the system uses only the relative pressure comparison between struts, effectively extracting the essential information needed for CG determination while eliminating the need for complex total weight measurement equipment
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
Enables accurate aircraft center of gravity determination without weight measurement, reducing the risk of flight delays and allowing for more efficient load placement and fuel savings by optimizing CG positioning.
Implementation Method 1
measuring the load supported by each of the main landing gear struts and measuring the load supported by the nose landing gear strut
Data Source
AI summary
A method which determines aircraft Center of Gravity independent of measuring the aircraft weight. The method is used in monitoring, measuring and computing the Center of Gravity of an aircraft utilizing pressurized, telescopic landing gear struts with axles. Pressure sensors are mounted in relation to each of the landing gear struts to monitor, measure and record aircraft landing gear strut loads by way of pressure. Axle deflection sensors are mounted in relation to each of the landing gear axles to monitor, measure and record aircraft landing gear axle loads by way of deflection. Nose landing gear strut pressure and corresponding values from axle deflection sensors may be adjusted in correlation to the reduced size of the nose landing gear, as compared to the size of the main landing gear, allowing aircraft Center of Gravity to be determined from the combined measured main landing gear pressures in relation to a nose landing gear strut pressure measurements, or combined main landing gear axle deflection sensor in relation to a nose landing gear axle deflection sensor; without any determination of the aircraft weight.