Aircraft Probe Heater Life Prediction via Leakage Current

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Solution Overview

Problem

Aircraft sensor probes face maintenance challenges due to the harsh flight environment, particularly with ice buildup and the limited lifespan of their heating elements, leading to unpredictable failures and delays.

Innovation Solution

A system and method for monitoring the characteristics of the probe's resistive heating element over time, using sensors to detect changes in current, capacitance, thermal images, and resonant frequency, allowing for the prediction of remaining useful life and timely replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heating element operates continuously in harsh flight conditions, then it prevents ice buildup and maintains probe functionality, but its lifespan decreases and it eventually fails

Engineering Contradiction:
Improveprobe functionalityVSAvoidheating element lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system performs preliminary monitoring of heating element characteristics (resistance, current draw, temperature) to detect early signs of degradation before complete failure occurs. This allows proactive replacement scheduling that prevents unexpected failures while extending the usable life of the heating element through the entire degradation curve.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors heating element parameters and provides feedback about its remaining useful life. This feedback mechanism enables adaptive maintenance scheduling, where the replacement timing is optimized based on actual element condition rather than fixed time intervals, thus maximizing element lifespan while ensuring reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If the probe is replaced immediately when the heating element fails, then probe functionality is restored, but maintenance time and flight delays increase

Engineering Contradiction:
Improveprobe functionalityVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary monitoring of heating element characteristics (resistance, current draw, temperature) to detect early signs of degradation before complete failure occurs. This allows proactive replacement scheduling that prevents unexpected failures while extending the usable life of the heating element through the entire degradation curve.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The maintenance schedule is made dynamic rather than static. Instead of replacing probes on fixed intervals, the system adjusts replacement timing based on actual heating element condition and predicted remaining useful life, allowing extensions beyond traditional schedules when elements are still functional and reducing replacements when elements fail unexpectedly.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple monitoring parameters are tracked to predict remaining useful life, then prediction accuracy improves, but system complexity increases

Engineering Contradiction:
Improveremaining useful life prediction accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The monitoring system is designed to serve multiple functions simultaneously: it tracks heating element resistance, current draw, temperature, and overall probe performance through a single integrated sensor network. This multi-functional approach achieves high prediction accuracy without proportionally increasing system complexity, as the same hardware infrastructure supports multiple measurement objectives.

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

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 proactive maintenance by accurately determining the remaining useful life of the heating element, reducing unexpected failures and flight delays by allowing for scheduled replacements.

Implementation Method 1

heaters are implemented within the probe to prevent the formation of ice

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

monitoring a characteristic of the probe over time, such as a leakage current

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Implementation Method 3

thermal images

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3379266B1Probe heater remaining useful life determination
Publication Date: 2021.06.30 ROSEMOUNT AEROSPACE INC
  • EP3379266B1 patent drawingFigure 1
  • EP3379266B1 patent drawingFigure 2A
  • EP3379266B1 patent drawingFigure 2B

AI summary

A system and method for an aircraft includes a probe, first and second current sensors, and a control circuit. The probe includes a heater that includes a resistive heating element routed through the probe, wherein an operational current is provided to the resistive heating element to provide heating for the probe. The first current sensor is configured to sense a first current through the resistive heating element, and the second current sensor is configured to sense a second current through the resistive heating element. The control circuit is configured to determine a leakage current based on the first and second currents and determine a remaining useful life the probe based on the leakage current over time.