Aircraft Door Lock Monitoring with Sensor-Based Visual Status

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Solution Overview

Problem

Existing mechanical door locking systems in aircraft are prone to wear due to vibrations and accelerations, leading to ambiguous indications and unreliable verification of the locked or unlocked state, especially in adverse conditions.

Innovation Solution

A locking system with multiple position sensors per lock, a controller, and an alarm that generates distinct visual alerts based on lock states, allowing reliable visual confirmation of lock engagement or disengagement, and is independent of the aircraft's avionics system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical systems with moving parts are used to indicate lock status, then visual verification is provided, but the system is subject to wear due to vibrations and accelerations

Engineering Contradiction:
Improvelock status indication reliabilityVSAvoidsystem service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces mechanical moving parts with optical sensors and electronic signaling systems. The lock status is detected using optical sensors that sense the position of lock components without mechanical contact, and the status is transmitted electronically to the alarm panel, eliminating wear from vibrations and accelerations while maintaining reliable visual verification.

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

Solution Approach 2:

The patent introduces an intermediary electronic signaling system between the lock mechanism and the visual indication. Instead of direct mechanical linkage, electrical signals serve as intermediaries to transmit lock status information from sensors to the alarm panel, reducing mechanical wear while preserving reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If mechanical systems are used to indicate lock status, then visual verification is provided, but ambiguous information is displayed when the door is ajar

Engineering Contradiction:
Improvelock status information clarityVSAvoidlock state detection accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent implements a feedback system where optical sensors continuously monitor the actual position of lock components and provide real-time status information to the control system. This feedback mechanism ensures accurate distinction between locked, unlocked, and ajar states, eliminating ambiguous visual indications by providing clear, definitive status information.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces ambiguous mechanical indicators with precise optical sensing systems that can accurately detect and distinguish between different lock states including ajar conditions, providing clear unambiguous information through electronic signaling rather than mechanical position display.

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

Data Source

PatentEP4703259A1Aircraft door lock system having a monitoring system which indicates whether the lock system is in a locked or unlocked state
Publication Date: 2026.03.04 EUROCOPTER FRANCE SA
  • EP4703259A1 patent drawingFigure 1~2
  • EP4703259A1 patent drawingFigure 3~4
  • EP4703259A1 patent drawing

AI summary

The present invention relates to a locking system (20) for locking a door (15) comprising at least two locks (31). The locking system (20) has a position sensor (40) per lock (31), each position sensor (40) emitting a measurement signal carrying a locked or unlocked state of the associated lock (31), the signaling system (30) comprising a controller (50) receiving the measurement signals and being connected to an alarm (60), the controller (50) being configured to emit either an unlock signal (SDV) when at least one measurement signal carries an unlocked state of the associated lock or a locking signal if each measurement signal carries a locked state of the associated lock, the alarm (60) generating a visual unlock alert upon receipt of the unlock signal and a visual lock alert upon receipt of the lock signal.