Air Data Probe Heater Failure Prediction via Leakage Current Metrics

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Solution Overview

Problem

Unexpected failures of air data probes, particularly the resistive heating elements, lead to flight delays and operational costs, as existing technologies lack effective predictive maintenance solutions.

Innovation Solution

A system and method for predicting the failure of resistive heating elements in air data probes by sensing electrical metrics such as phase relation, time-domain profiles, and high-frequency components of the leakage current, allowing for preemptive maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional monitoring methods are used for heating elements, then device complexity is low, but reliability of prediction is insufficient

Engineering Contradiction:
Improveprediction reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary monitoring system that senses electrical metrics (current, voltage, impedance) of the heating element without directly contacting or modifying the heating element itself. This intermediary approach enables reliable failure prediction through parameter analysis while keeping the overall system complexity manageable by using non-invasive sensing methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical or visual inspection methods with electrical sensing and analysis. By substituting physical examination with electrical metric monitoring (current, voltage, impedance measurements), the system achieves higher prediction reliability while maintaining low complexity through electronic rather than mechanical means.

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

2Loss of time

If no predictive maintenance is implemented, then device complexity is low, but loss of time due to flight delays increases

Engineering Contradiction:
Improveflight delay timeVSAvoidmaintenance system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by continuously monitoring heating element parameters and detecting early signs of degradation before actual failure occurs. The system performs preliminary diagnostics through electrical metric analysis, enabling maintenance to be scheduled in advance and preventing unexpected failures that would cause flight delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback loop where electrical metrics from the heating element are continuously measured, analyzed, and used to update the health status assessment. This feedback mechanism provides real-time information about element condition, enabling timely maintenance decisions that reduce flight delays while maintaining manageable system complexity.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If detailed electrical parameter monitoring is implemented, then measurement precision is high, but device complexity increases

Engineering Contradiction:
Improveparameter measurement precisionVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent achieves high measurement precision through a universal monitoring approach that uses standard electrical sensing components to measure multiple parameters (current, voltage, impedance) simultaneously. This multi-functional sensing system obtains comprehensive diagnostic information without requiring separate specialized sensors for each parameter, thereby maintaining measurement precision while controlling system complexity.

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 accurate prediction of resistive heating element failure, facilitating timely maintenance and reducing flight delays and operational costs by estimating the remaining useful life of the elements.

Implementation Method 1

Air data probes typically include resistive heater elements to prevent operational issues relating to in-flight ice buildup

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

The insulator creates a very high electrical resistance between the metallic sheath (often electrically connected to the body of the probe) and the heater wire itself

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

The presence of the heater wire, insulator, and metallic sheath also creates a capacitance between the sheath and the heater wire

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4067911B1Predicting failure and estimating remaining useful life of an air-data-probe heater
Publication Date: 2025.06.18 ROSEMOUNT AEROSPACE INC
  • EP4067911B1 patent drawingFigure 1
  • EP4067911B1 patent drawingFigure 2
  • EP4067911B1 patent drawingFigure 3

AI summary

Apparatus (22) and associated methods relate to predicting failure and/or estimating remaining useful life of an air-data-probe heater. Failure is predicted or useful life is estimated based on an electrical metric of the electrical operating power provided to a resistive heating element (24) of the air-data-probe heater. The electrical metric of the air data probe heater is one or more of: i) phase relation between voltage across the resistive heating element and leakage current, which is conducted from the resistive heating element to a conductive sheath surrounding the resistive heating element; ii) a time-domain profile of leakage current through the heating element insulation during a full power cycle; and/or iii) high-frequency components of the electrical current conducted by the resistive heating element and/or the voltage across the resistive heating element.