Fuel Jettison System Independent Tank Balance Control
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Solution Overview
Problem
Conventional aircraft fuel jettison systems lack the ability to independently manage fuel jettisoning from multiple tanks to maintain equal balance, relying on predefined fuel levels and auxiliary pumps, which complicates aircraft control and increases installation costs.
Innovation Solution
A fuel jettison system with an overboard conduit, fuel pump, shutoff valve, and dip conduit, controlled by a fuel management system that uses pilot-initiated automatic and manual operations to jettison fuel independently from multiple tanks, ensuring equal balance by communicating with fuel level probes and utilizing inward venting for complete purge and ground support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fuel jettison systems use auxiliary pumps within each fuel tank, then fuel can be pumped to an overboard location, but the system complexity and installation expense increase significantly
Solution Approach 1:
The patent combines the fuel jettison function with the existing fuel transfer pump system. Instead of installing separate auxiliary pumps in each fuel tank, the system uses the existing fuel transfer pumps that already circulate fuel between tanks. The fuel jettison conduit is integrated into the existing fuel system architecture, merging multiple functions into a unified system that reduces overall complexity.
Solution Approach 2:
The existing fuel transfer pumps are made multi-functional by enabling them to perform both their original fuel transfer function and the additional fuel jettison function. The fuel management control system directs these pumps to operate in jettison mode when required, allowing a single pump system to serve multiple purposes without requiring dedicated auxiliary pumps for each tank.
2Ease of operation
If conventional fuel jettison systems jettison to a predefined useable fuel remaining level, then the jettison process is simplified, but aircraft fuel balance control is compromised
Solution Approach 1:
The system implements feedback control by continuously monitoring fuel quantities in multiple tanks through the fuel management control system. The control algorithms receive real-time fuel quantity data and automatically adjust the jettison process by controlling shutoff valves to maintain equal fuel balance across tanks. This feedback mechanism ensures precise fuel balance control while the pilot only needs to initiate the jettison process with a single switch activation.
Solution Approach 2:
The jettison system dynamically adjusts the jettison rate and termination points based on real-time fuel quantity measurements. The control algorithms modify the jettison process dynamically by opening and closing shutoff valves at different tanks at different times, ensuring that fuel is removed proportionally from each tank to maintain aircraft balance. This dynamic control allows the system to adapt to changing fuel conditions while maintaining simplicity for the pilot.
3Device complexity
If a single fuel jettison conduit is used for multiple fuel tanks, then the system is simplified, but the ability to independently jettison from each tank is lost
Solution Approach 1:
The fuel jettison system is segmented by providing separate fuel jettison conduits for each fuel tank rather than using a single common conduit. Each tank has its own dedicated conduit that connects to the common overboard discharge point. This segmentation allows the fuel management control system to independently control jettison from each tank by placing shutoff valves at different locations in the system, enabling selective closure of individual tank conduits while maintaining a relatively simple overall conduit architecture.
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 system effectively maintains aircraft balance by independently jettisoning fuel to specific remaining levels, reducing the risk of imbalance and minimizing fuel loss, while allowing for accessible manual override and efficient ground support operations.
Implementation Method 1
The shutoff valve is powered open by an actuator such as a solenoid valve
Implementation Method 2
a fuel pump in communication with the overboard fuel jettison conduit and the fuel jettison conduit
Data Source
AI summary
A fuel jettison system which provides pilot-initiated automatic operation to jettison fuel down to a 60 minute useable fuel remaining level while the manual operation, requiring the pilot to hold down the jettison panel switch, jettisons fuel down to a 20-minute useable fuel remaining level. The pilot can interrupt jettisoning at any time. This termination sequence operates in either automatic or manual mode. The port and starboard main fuel tanks jettison fuel independently through independent shutoff valves and associated circuit logic to thereby maintain aircraft balance.