Aircraft Engine Cut-Off Confirmation via Multi-Switch Time Window

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Solution Overview

Problem

Current aircraft engine shutdown systems lack robust safety mechanisms to confirm that the actuation of an engine cut-off control corresponds to the pilot's intention, especially during flight operations.

Innovation Solution

A control system with an engine cut-off confirmation unit that includes electronic circuitry to monitor the position of multiple switches over a predefined time window, ensuring that the engine shutdown aligns with the pilot's intention by verifying the fuel supply cut-off state and propulsion motor speed, and maintaining confirmation only when the engine is fully shut down.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple switch mechanism is used for engine cut-off control, then the ease of operation is improved, but the reliability is worsened due to lack of confirmation mechanisms

Engineering Contradiction:
Improveease of operationVSAvoidreliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary verification by monitoring switch positions before executing the engine cut-off command. The electronic circuitry checks that all required switches are in the correct position for a predetermined time period before enabling the fuel cut-off, ensuring the pilot's intention is confirmed before action is taken.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the positions of multiple switches and providing confirmation signals to the fuel cut-off mechanism. The electronic circuitry verifies switch positions and only permits engine shutdown when all switches indicate intentional pilot command, creating a feedback loop that ensures reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple switches are monitored with time window verification, then the reliability is improved, but the device complexity is worsened

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electronic circuitry performs multiple functions: it monitors switch positions, determines when all switches are in the correct position, tracks the duration of switch positions within time windows, and controls the fuel cut-off enable signal. This multi-functional approach consolidates what could be separate complex systems into a single integrated circuit.

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

Solution Approach 2:

The electronic circuitry automatically monitors its own operational state by tracking switch positions and time windows, and self-regulates the fuel cut-off enable signal based on verified conditions. The system serves itself by internally managing the verification process without requiring external complex control mechanisms.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3909860B1System for confirming cut-off of an aircraft engine
Publication Date: 2022.07.06 AIRBUS OPERATIONS (SAS)
  • EP3909860B1 patent drawingFigure 1~2
  • EP3909860B1 patent drawingFigure 3A~3B
  • EP3909860B1 patent drawingFigure 4~5

AI summary

To control an engine shutdown in an aircraft (100), a control system (110) includes a fuel shut-off device (120); a control unit, which includes a set of switches, a first switch on an electrical supply link (130) to the fuel shut-off device and a plurality of second switches connected to aircraft avionics, the set of switches toggling from position to engine shutdown command. An engine shutdown confirmation unit includes a third switch located on the electrical supply link, the third switch being in the open position by default.The motor shutdown confirmation unit includes electronic circuitry configured to flip the third switch to the closed position when a predefined number Q of the control unit's switches flip within a predefined sliding window of duration, and otherwise keeps the third switch in the open position. This ensures that the motor shutdown is intentional.