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Fuselage Leak Detection by Monitoring Cabin Pressure Control System Outflow Valve

IP.com Disclosure Number: IPCOM000241926D
Publication Date: 2015-Jun-09
Document File: 6 page(s) / 294K

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The IP.com Prior Art Database

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0130413445, 9780130413444: ISBN

Abstract

Leaks developed in an aircraft cabin, if not detected early, can cause depressurization and can consequently lead to conditions such as decreasing cabin air quality, passenger hypoxia etc. Hence, it is required to identify and continuously monitor slowly developing as well as rapidly developed fuselage leaks. This paper provides a method for detecting cabin air leakages by monitoring the extent of opening or closing of cabin air pressure control system outflow valves.

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Fuselage Leak Detection by Monitoring Cabin Pressure Control System Outflow Valve

Michael McGill, Darrell Horner, Andrew Peter Vechart

ABSTRACT

Leaks developed in an aircraft cabin, if not detected early, can cause depressurization and can consequently lead to conditions such as decreasing cabin air quality, passenger hypoxia etc. Hence, it is required to identify and continuously monitor slowly developing as well as rapidly developed fuselage leaks. This paper provides a method for detecting cabin air leakages by monitoring the extent of opening or closing of cabin air pressure control system outflow valves.


1. INTRODUCTION

As the altitude of an aircraft increases, the ambient atmospheric pressure outside decreases. Leakages developed in an aircraft cabin can cause it to decompress to an undesirably low pressure at high altitudes. Depressurization can cause hypoxia in passengers and has many other fatal consequences. Leaks could lead to a cabin air pressure control system malfunction that can render the whole aircraft non-functional. Therefore, it is beneficial to continuously look for slowly developing as well as rapidly developing leaks in the cabin using already functional equipment on the aircraft.

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2. PROPOSED SOLUTION OF THE PROBLEM

This solution provides a way to detect leaks from any source in the aircraft cabin such as doors, windows, etc. It is able to predict when the cabin leaks will exceed the ability of the cabin pressure control system outflow valve to compensate, leading to an underpressurization of the cabin.

To monitor or detect cabin air leakage, this solution makes use of the information about the door angle of the cabin air pressure control system outflow valve. The cabin air pressure control system outflow valve (OFV) functions by opening and closing to increase or decrease the rate at which air is vented from the cabin in order to maintain a pressure set point. If the cabin pressure is too low, the OFV closes more; if the cabin pressure is too high, the OFV opens farther. For a given airplane altitude, targeted cabin pressure, and air inflow rate, the OFV is modulated about a consistent operating angle. As leaks start to develop in the cabin, the OFV angle will tend to be in farther closed positions over time. Thus, monitoring of the door angle over time provides insight into the cabin air leakage status.

The OFV angle information is accessible either directly from the OFV position sensor signal, or from the OFV controller, which reads this OFV sensor signal as part of the control system.


3. DESIGNING THE FEATURE

An algorithm for monitoring the cabin air pressure control system valves during flight is described below:

These are steps performed by different software systems involved in this process such as cabin pressure controller software, bleed air / air conditioning system software, maintenance system software, ventilation system software, etc.

Step 1. Cabin pressure controller software:

a...