Landing Gear Position Sensor Bounce Detection System

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Solution Overview

Problem

Aircraft may bounce off the runway during landing due to high winds or improperly serviced landing gear, leading to premature de-rotation and potential structural damage, as pilots may not recognize the bounce due to cockpit movement misaligning with main landing gear position relative to the ground.

Innovation Solution

An Airplane Off Ground Advisory System (AOGAS) using position sensors on the main landing gear to detect extension and compression, triggering a control system that activates indicator lights in the cockpit to alert the flight crew of an off-ground condition, ensuring a safe landing or go-around maneuver.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pilots rely on cockpit movement perception to detect landing bounce, then the system is simple and requires no additional sensors, but the detection reliability deteriorates because cockpit movement does not accurately reflect main landing gear position relative to the ground

Engineering Contradiction:
Improvebounce detection reliabilityVSAvoidsensor and control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces position sensors on the main landing gear as an intermediary device that directly measures the gear's position relative to the ground, rather than relying on cockpit movement perception. This intermediary measurement system accurately detects bounce conditions by monitoring when the landing gear extends after compression during touchdown, providing reliable bounce detection independent of cockpit position changes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If position sensors and control systems are added to detect landing bounce, then detection reliability improves, but the device complexity increases due to additional sensors, control logic, and indicator systems

Engineering Contradiction:
Improvelanding condition detection accuracyVSAvoidnumber of sensors and control components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback system where position sensors continuously monitor main landing gear position and provide signals to a control system. The control system processes these signals to detect the bounce condition (extension after compression) and provides immediate feedback to pilots through cockpit indicators. This closed-loop feedback ensures accurate and timely bounce detection while maintaining systematic simplicity through automated control logic.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses the landing gear's own position sensors to detect bounce conditions, allowing the landing gear system to self-monitor its state. The position sensors on the main landing gear directly measure extension and compression, and the control system automatically processes this information to generate bounce warnings, eliminating the need for separate detection systems or pilot interpretation of cockpit movements.

Inventive Principle:
Principle #25Self-service

3Reliability

If the system provides immediate bounce indication, then pilot response time is reduced and safety improves, but false alerts from minor bounces may cause unnecessary go-around maneuvers

Engineering Contradiction:
Improvesafe landing assuranceVSAvoidfalse alert impact on landing operation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a dynamic detection algorithm that monitors the sequence and duration of landing gear position changes. The control system distinguishes between minor bounces (brief, small-amplitude extensions) and significant bounces (prolonged or repeated extensions) by analyzing the temporal characteristics of position sensor signals. This dynamic analysis allows the system to provide timely warnings for dangerous bounce conditions while filtering out minor disturbances that do not require go-around maneuvers.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2868584B1Airplane off ground advisory system
Publication Date: 2017.09.06 THE BOEING CO
  • EP2868584B1 patent drawingFigure 1
  • EP2868584B1 patent drawingFigure 2
  • EP2868584B1 patent drawingFigure 3

AI summary

An airplane off ground advisory system employs at least one position sensor (218a, 218b) attached for detection of an extended condition and a compressed condition of a main landing gear (MLG, 12a, 12b). A control system (200) receives an input from the position sensor (218a, 218b). The control system (200) records a toggling of the input from an extended to a compressed to an extended condition and providing an output. At least one indicator (222a, 222b) is coupled to the control system (200) to be activated by the output.