Pyrotechnic Door Latch Actuation for Aircraft Decompression Response

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Solution Overview

Problem

Existing electromechanical door latch systems in aircraft operate too slowly during decompression events, leading to potential structural damage and risk of aircraft loss.

Innovation Solution

A pyrotechnic latch actuator is integrated with an electromechanical system to accelerate the operation of the door latch, utilizing pyrotechnic deflagration to rapidly move the latch bolt, with redundant pyrotechnic actuators for backup and self-reset capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If electromechanical door latch is used, then the door latch can be locked or unlocked, but the operation speed is too slow during decompression events

Engineering Contradiction:
Improvedoor latch operation speedVSAvoidstructural integrity during decompression
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent combines electromechanical actuation with pyrotechnic actuation in a hybrid door latch system. The electromechanical motor provides controlled operation during normal conditions, while pyrotechnic charges provide rapid actuation during decompression events. Both actuation systems work together on the same latch mechanism, merging their advantages to achieve both reliability and speed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system dynamically switches between electromechanical and pyrotechnic actuation modes based on flight conditions. During normal operation, the electromechanical system provides controlled, quiet operation. During detected decompression events, the system dynamically transitions to pyrotechnic actuation for immediate response, optimizing performance for each operational state.

Inventive Principle:
Principle #15Dynamics

2Loss of time

If pyrotechnic actuator is added to accelerate door latch operation, then the response time is reduced, but the device complexity increases

Engineering Contradiction:
Improveresponse time during decompressionVSAvoidlatch actuator system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The hybrid actuator system serves multiple functions: the electromechanical motor handles normal locked/unlocked operations, while the pyrotechnic charges handle emergency decompression events. This multi-functionality allows a single integrated system to address both routine and emergency scenarios, reducing the need for separate systems and minimizing overall complexity.

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

Solution Approach 2:

The control system acts as an intermediary that manages both electromechanical and pyrotechnic actuators. It receives inputs from pressure sensors, determines when decompression events occur, and selectively activates the appropriate actuation mechanism. This intermediary control layer simplifies the interface between the two actuation systems and the rest of the aircraft systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If redundant pyrotechnic actuators are implemented, then the system reliability is improved, but the weight and complexity increase

Engineering Contradiction:
Improvesystem redundancyVSAvoidactuator system weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

Rather than duplicating the entire actuator system throughout the aircraft, redundancy is implemented locally at each door latch assembly. Each door has its own pyrotechnic actuator integrated with the electromechanical system, providing localized backup without the weight penalty of a centralized redundant system. This local quality approach ensures that each door can independently respond to decompression events.

Inventive Principle:
Principle #3Local quality

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

The pyrotechnic latch actuator provides immediate and rapid operation, minimizing structural damage by equalizing pressure between compartments and preventing aircraft loss during decompression events.

Implementation Method 1

The pyrotechnic actuator is configured to move the latch bolt when the pyrotechnic actuator is actuated... utilizing pyrotechnic deflagration to rapidly move the latch bolt

Methodology Applied
Scientific EffectPyrotechnic deflagration: Deflagration

Implementation Method 2

The pyrotechnic device gases are forced out of the chamber through the spring action. The pyrotechnic devices can be designed for replacement after a decompression, or a false activation.

Methodology Applied
Scientific EffectSpring action: Spring

Data Source

PatentEP4450740B1Pyrotechnic latch actuator responsive to a decompression detection system and method
Publication Date: 2026.03.11 ADAMS RITE AEROSPACE
  • EP4450740B1 patent drawingFigure 1
  • EP4450740B1 patent drawingFigure 2
  • EP4450740B1 patent drawingFigure 3

AI summary

A system for monitoring a pressure change within at least one compartment of an aircraft and operating a pyrotechnic device associated with a door latch, includes a securing mechanism arranged in an aircraft door that includes a pyrotechnic actuator and a latch bolt. The system includes the pyrotechnic actuator configured to move the latch bolt when the pyrotechnic actuator is actuated. The system also includes a pressure sensor configured to provide a pressure signal. The system also includes a controller configured to determine a pressure drop representing a decompression event. The system also includes an output driver configured to generate an output signal to actuate the pyrotechnic actuator when the controller determines the occurrence of a decompression event.