Automated Fuel Cutoff Testing System for Aircraft Engines

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Solution Overview

Problem

Current methods for determining the minimum controllability speed of an aircraft during engine failure are inaccurate and require repeated testing, leading to increased wear and tear on the aircraft, higher fuel consumption, and inconsistent data due to the reliance on human operators to move a fuel control switch to the cutoff position.

Innovation Solution

An automated system comprising a switch, a test processor, a relay, and a lifter structure that identifies the cutoff speed and delay to precisely stop engine fuel flow, reducing the need for human intervention and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a human operator manually moves the fuel control switch to the cutoff position during testing, then the test can be performed, but the accuracy of achieving the desired cutoff speed is poor and data consistency is reduced

Engineering Contradiction:

Improvecutoff speed accuracyVSAvoidmanual switch operation difficulty

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the manual mechanical operation of moving the fuel control switch with an automated electrical control system. The test processor electronically controls the fuel control switch based on real-time speed feedback, eliminating the need for manual pilot intervention and achieving precise cutoff speed control through automated signal processing and actuation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The testing system performs self-regulation by automatically monitoring aircraft speed, calculating the optimal timing for fuel cutoff, and actuating the fuel control switch without external human intervention. The system uses feedback from speed sensors to autonomously determine when to cutoff fuel flow, achieving consistent and accurate test results.

Inventive Principle:

Principle #25Self-service

2Reliability

If repeated tests are performed to obtain consistent data, then data reliability may improve, but aircraft wear and fuel consumption increase

Engineering Contradiction:

Improvedata consistencyVSAvoidfuel consumption and aircraft wear

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a feedback control system where the test processor continuously monitors aircraft speed through sensors and uses this information to precisely time the fuel cutoff event. This closed-loop control ensures accurate achievement of the desired cutoff speed on the first attempt, eliminating the need for repeated tests and reducing fuel consumption and aircraft wear.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary calculations and preparations before the actual cutoff event. The test processor pre-determines the optimal cutoff timing based on the desired cutoff speed and current acceleration rate, then automatically executes the fuel cutoff at the precise moment, ensuring data reliability without requiring multiple test repetitions.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the pilot anticipates and manually moves the fuel control switch at the selected speed, then the test can be conducted, but the effort and concentration required increase operational difficulty

Engineering Contradiction:

Improvetest execution efficiencyVSAvoidpilot workload

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent replaces the pilot's manual mechanical operation of the fuel control switch with an automated electrical control system. The test processor electronically actuates the fuel control switch based on real-time speed feedback, completely eliminating the need for pilot intervention and significantly reducing operational workload while improving test execution efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Extent of automation

If manual fuel control switch operation is used, then the system remains simple, but measurement precision and automation level are limited

Engineering Contradiction:

Improvefuel cutoff control automationVSAvoidtesting system complexity

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical switch operation with an automated electrical control system comprising a test processor, speed sensors, and electronic actuation mechanisms. This substitution significantly increases the extent of automation while the modular architecture and integration with existing aircraft systems keep the added complexity manageable.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2974965B1Fuel cutoff testing system

Publication Date: 2017.11.01 THE BOEING CO

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AI summary

A method and apparatus for controlling operation of an engine (226) in an aircraft (202). A time (244) when a cutoff speed (246) for the aircraft (202) will be reached at which a flow of fuel (224) is to be stopped is identified. A delay (248) between sending a command (250) to move a switch (214) to an off position (222) and the time (244) at which the engine (226) ceases operation is also identified. The command (250) is sent based on the predicted time (244) and the delay (248). The command (250) causes the switch (214) to move to the off position (222) moving a fuel control switch (238) for the engine (226) of the aircraft (202) to a shut off position (242) to stop the flow of fuel (224) to the engine (226).