Cargo Fire-Suppression Agent Distribution System for Class E Aircraft
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Solution Overview
Problem
Existing all-cargo aircraft lack active fire-suppression agent capability in class E cargo compartments, relying on airflow control and depressurization to manage fires, which can lead to smoldering and potential re-ignition during descent and landing.
Innovation Solution
A cargo-fire-suppression agent distribution system that receives a fire-warning signal and distributes an initial fire-suppression agent during depressurization and an re-enforcing agent during re-pressurization, maintaining suppression until landing to prevent smoldering and re-ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If depressurization is used to suppress fire in class E cargo compartment, then oxygen partial pressure is reduced to suppress active flame, but fire may continue to smolder and potentially re-ignition during descent and landing
Solution Approach 1:
The system distributes an initial fire-suppression agent during the depressurization phase before the aircraft reaches the second altitude, proactively suppressing the fire before it can smolder or re-ignite during descent. This preliminary action prevents the harmful effect of smoldering that would otherwise occur during the descent phase.
Solution Approach 2:
The system maintains continuous fire suppression by distributing a re-enforcing fire-suppression agent during the re-pressurization phase and maintaining it through landing. This continuous action ensures that fire suppression effectiveness is maintained throughout the entire flight profile, preventing smoldering and re-ignition risks during descent and landing.
2Reliability
If fire-suppression agent is distributed during depressurization phase, then initial fire suppression is achieved, but additional agent is needed during re-pressurization to maintain suppression
Solution Approach 1:
The fire-suppression agent distribution is segmented into two distinct phases: an initial distribution during depressurization and a re-enforcing distribution during re-pressurization. This segmentation allows the system to address fire suppression needs at different flight stages, ensuring reliability while managing the quantity of agent required through phased deployment.
Solution Approach 2:
The system employs periodic action by distributing the re-enforcing fire-suppression agent at specific intervals - during the re-pressurization phase when cabin altitude is below a predetermined level. This periodic reinforcement maintains suppression effectiveness without requiring continuous high-volume agent distribution, optimizing the quantity used.
3Ease of operation
If existing class E cargo compartment procedures are used (airflow shutdown and depressurization), then operational simplicity is maintained, but active fire suppression capability is lacking
Solution Approach 1:
The fire-suppression agent distribution system is integrated with the existing depressurization and airflow control procedures, allowing the same operational framework to serve both traditional class E functions and active fire suppression. This multi-functionality maintains ease of operation while adding reliable fire suppression capability.
Solution Approach 2:
The system utilizes the aircraft's existing depressurization and re-pressurization cycles to trigger and time the fire-suppression agent distribution, rather than requiring separate independent control systems. The fire suppression system serves itself by leveraging the aircraft's normal operational phases, maintaining simplicity while enhancing capability.
Data Source
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AI summary
A cargo-fire-suppression agent distribution system and methods are presented. A fire-warning signal indicating presence of fire in a cargo compartment onboard a class E cargo aircraft at a first altitude is received. An initial fire-suppression agent is distributed in the cargo compartment at the first altitude sufficient to suppress fire for an initial fire suppression time interval during a depressurization phase during which the class E cargo aircraft flies to a second altitude below the first altitude. A re-enforcing fire-suppression agent is distributed in the cargo compartment during a re-pressurization phase when a cabin altitude is below a predetermined cabin pressure level (PL) during which the class E cargo aircraft flies from the second altitude to a landing, after the initial fire-suppression time interval elapses. The re-enforcing fire-suppression agent distribution is maintained during a re-enforcing fire-suppression time interval.