Fuselage-Stowed Multi-Stage Evacuation Slides for Aircraft Raft Deployment

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Solution Overview

Problem

Existing emergency evacuation systems in aircraft are limited by door-mounted slides that reduce cabin space, require stronger doors, and fail to function reliably as rafts during water landings due to air-entrainment devices being submerged.

Innovation Solution

A multi-stage evacuation system with a closed inflation system using a self-contained reservoir and an open inflation system with air-entrainment, allowing the slide/raft to deploy and inflate from a fuselage compartment, ensuring functionality even when submerged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the emergency evacuation system is stored within the door, then the slide can deploy reliably, but the available space within the internal cabin is decreased

Engineering Contradiction:
Improvecabin spaceVSAvoidslide deployment reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The evacuation slide is extracted from the door assembly and relocated to a dedicated stowage compartment in the fuselage. This separation allows the door to be lighter and smaller while the slide maintains its deployment reliability through a dedicated deployment mechanism that activates when the door opens.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The evacuation system is segmented into independent components: the door assembly, the stowage compartment, and the slide mechanism. This segmentation allows each component to be optimized independently - the door for weight and size reduction, and the slide for reliable deployment from its dedicated compartment.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the air-entrainment device is submerged during water landing, then the inflation system cannot function, but the slide/raft cannot deploy as a life raft

Engineering Contradiction:
Improveraft deployment reliabilityVSAvoidwater submersion effect
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by deploying the slide structure and positioning the air-entrainment device above the water surface before inflation begins. The slide rails and structural framework extend upward from the stowage compartment, ensuring that when the door opens during water landing, the inflation apparatus is already in a position to access ambient air.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The slide structure acts as an intermediary mechanism that connects the submerged stowage compartment with the ambient air above water. The rigid slide rails and framework extend upward from below the water line to support the air-entrainment device above the water surface, mediating between the submerged storage location and the air needed for inflation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If door-mounted slides require stronger doors with heavier hinges and larger liners, then the door structure is reinforced, but the internal cabin space is intruded upon

Engineering Contradiction:
Improvedoor structure strengthVSAvoidcabin volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The heavy-duty door reinforcement requirements are extracted from the door assembly by relocating the slide to a fuselage-mounted stowage compartment. The door no longer needs to support the weight and structural demands of the slide mechanism, allowing for lighter door construction with smaller liners that intrude less into cabin space.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The slide system is moved from the vertical door plane to the horizontal fuselage dimension. By mounting the stowage compartment in the fuselage below the door rather than within the door itself, the system resolves the conflict between door strength requirements and cabin space by utilizing unused fuselage volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 flexible seating arrangements, reduces door weight and size, and ensures reliable raft deployment in water, eliminating the need for supplemental life rafts.

Implementation Method 1

The internal inflator includes a reservoir of compressed gas

Methodology Applied
Scientific EffectCompressed gas storage: Compression

Implementation Method 2

The open inflation system includes one or more air-entrainment devices

Methodology Applied
Scientific EffectAir entrainment: Air Entrainment

Implementation Method 3

the inflated first floatation device disposes the open inflation system of the second floatation device above water

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP4169839B1Multi-stage evacuation systems and methods for aircraft
Publication Date: 2025.09.17 THE BOEING CO
  • EP4169839B1 patent drawingFigure 1
  • EP4169839B1 patent drawingFigure 2
  • EP4169839B1 patent drawingFigure 3~5

AI summary

An emergency evacuation system (102) is configured to be stored in a compartment below an exit door of an aircraft (10). The emergency evacuation system (102) includes a first floatation device including an internal inflator (126), and a second floatation device including an open inflation system (130). The second floatation device is coupled to the first floatation device.