Fiber Optic Landing Gear Fire Detection and Fatigue Monitoring

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Solution Overview

Problem

Existing aircraft overheat detection systems, such as those using eutectic salt technology, provide only binary indications of overheat events and lack the capability to monitor temperature and strain conditions accurately, limiting their effectiveness in detecting overheats and potential failures in aircraft landing gear systems.

Innovation Solution

A dual overheat and strain detection system utilizing optical signals transmitted through fiber optic loops, which includes an optical controller, transmitter, and receiver to analyze temperature and strain data across multiple zones of an aircraft, providing detailed temperature and strain profiles and generating alarms based on specific threshold values, thereby enabling precise monitoring and early detection of overheat or strain events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If eutectic salt technology is used for overheat detection, then overheat events can be detected, but only binary indications are provided without detailed temperature monitoring capability

Engineering Contradiction:
Improvetemperature monitoring precisionVSAvoiddetailed temperature data
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces the mechanical/electrical eutectic salt sensor system with an optical fiber-based detection system. The fiber optic cable acts as both the structural element and the sensing element, eliminating the need for separate eutectic salt sensors while providing continuous temperature monitoring capability through optical signal analysis.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fiber optic cable serves multiple functions simultaneously: it provides structural reinforcement to the landing gear component and acts as a distributed temperature sensor. This multi-functionality eliminates the need for separate sensing elements and enables detailed temperature profiling along the entire length of the fiber.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If eutectic salt sensors are deployed, then overheat detection is achieved, but separate sensors are required increasing system complexity

Engineering Contradiction:
Improveoverheat detection reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the structural reinforcement function and the temperature sensing function into a single integrated system. The fiber optic cable is embedded within or attached to the landing gear component, combining structural support with distributed temperature sensing, thereby reducing the number of separate components and simplifying the overall system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fiber optic cable performs dual functions as both a structural element providing reinforcement and as a sensing element for temperature monitoring. This eliminates the need for separate eutectic salt sensors and their associated wiring and electronics, reducing system complexity while maintaining detection reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If traditional overheat detection systems are used, then basic overheat alarm is provided, but detailed temperature profiles and strain monitoring are not available

Engineering Contradiction:
Improvepreventative maintenance capabilityVSAvoidtemperature and strain data
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The system provides continuous feedback on temperature and strain conditions along the landing gear component through the fiber optic network. The optical controller analyzes signals from the fiber to generate real-time temperature and strain profiles, enabling operators to monitor component health and perform preventative maintenance based on actual measured data rather than binary alarm states.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional electrical sensing methods with optical sensing technology. The fiber optic cable uses optical signal properties to detect temperature and strain changes, providing rich diagnostic information without the limitations of electrical sensors. This substitution enables detailed profiling capabilities that enhance preventative maintenance operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system allows for real-time monitoring of temperature and strain across aircraft zones, providing detailed data for preventative maintenance, reducing downtime, and enabling faster detection of overheats and potential failures compared to traditional methods, while eliminating the need for separate eutectic salt sensors.

Implementation Method 1

an optical signal is provided to a fiber optic cable and an optical response signal is received from the fiber optic cable

Methodology Applied
Scientific EffectOptical signal transmission: Optical Fibre

Data Source

PatentEP3770568B1Integrated landing gear fire detection and fatigue monitoring system
Publication Date: 2023.07.19 KIDDE TECHNOLOGIES INC
  • EP3770568B1 patent drawingFigure 1
  • EP3770568B1 patent drawingFigure 2A
  • EP3770568B1 patent drawingFigure 2B~2D

AI summary

A system for an aircraft (12) that includes a plurality of zones including: a first fiber optic cable (26A, 26E, 26) routed through a zone of the plurality of zones. The first fiber optic cable (26A, 26E, 26) is attached to a landing gear (42A) of the aircraft (12) in the zone of the plurality of zones; and a first controller configured to provide a first optical signal to the first fiber optic cable (26A, 26E, 26) and obtain a first optical response signal from the first fiber optic cable (26A, 26E, 26). The first controller is further configured to determine at least one temperature within the zone of the plurality of zones based on the first optical response signal, the first optical signal, and coherent optical frequency domain reflectometry (COFDR).